Home Forums Hunting & Shooting BPCR 4ffffg

In a series of posts, Ranch13 asked, "So how many here use 4f in cartridges? Fellers this was mostly posted in frustration of the tongue lashing I took from another forum for calling someone, who loaded 82 grs of the stuff into a 40-82 case, fired the damn thing, lost a primer and is now concerned about how much pressure bp generates, and is convinced that Lyman's data is "questionable", bullheaded."

Digital Dan responded, "Well now, whyn't you invite him over here for a little chat?"

JB said, "First off Ranch I want to say that you were right in what you said in your responses over at Goex. Me thinks Dick Gunn need his own Lab to conduct his own experiments away from the safe and sane world. What was his point about fine black powders the English used in the .303 Brit cartridge... ie apples to oranges. I read the same postings over at Goex as well as other forum boards that Dick Gunn associates with, I do question his reasoning for it.... Many shooters today just are not happy unless they are making their bullets fly at a supercharge or spiking their feet per second rate for flatter trajectory, and that is what he appears to be trying to attain. My Opinion Expressed. Now lets get back to talking about normal loadings of Fg, FFg and FFFg."

Ranch13 responded, "I think that clown needs to be identified immediately should he arrive at any shoot, it would not be a good thing to have some innocent bystander injured because his gun come apart at the seams on account of the possibility of the case being a little long. ( Never friggin mind the over charge of powder.)"

JB followed up, "Ranch13, Your exactly right, if he is identified should he attend the Quigley this next year, I want to know who he is because I sure don't want him shooting on the squad I'm shooting with."


Reading the foregoing posts, it would seem that I am a bullheaded clown whose sanity is questionable, who is trying to supercharge BP cartridges, and who cannot be trusted because he might bring dangerous experimental loads to a match.

While folks are certainly entitled to express their opinions, I believe that in this case the above statements, opinions, and misinterpretations are not supported by the facts. The facts concerning my 4Fg velocity tests were extensively aired on the GOEX board and the MSN site, and I would have been happy to leave it there. But since I did not hide behind an anonymous handle, my name has now figured prominently in disparaging posts on this site, so I figure I better defend my good name.


This whole discussion started when I asked if anyone had access to laboratory pressure test data for BPCR cartridges. I'm trying to work up an equation for estimating BP pressures, so I need a lot of data points. There's a bunch of published information about peak pressures generated by muzzle loaders, but not a lot about BPCR pressures. Also, there appear to be some minor but persistent discrepancies between the BPCR pressure data published by Accurate, Lyman, and Spencer Wolfe. While these discrepancies are not very large, the fact that they exist does present a problem when trying to decide which pressure data points to use when developing my pressure equation. Hence the inquiry re: possible additional sources of pressure data.

So far so good. Nothing in the above request should have caused howls of protest or gross insults.

Regarding the 4Fg stuff, when I was working up some equations for estimating BPCR muzzle velocities, I got most of my data by chronographing a series of cartridges loaded with 1Fg, 2Fg, 3Fg, and 4Fg. This velocity measurement process was done in what I regard as a reasonable, safe, and prudent manner.

There was no question that the test loads of 1FG, 2Fg, and 3Fg would be safe, but working with 4Fg was an unknown territory. Since Spencer Wolfe's testing had shown only a 20% increase in peak pressure when shifting from 2Fg to 3Fg loads, an additional pressure increase 20% or 30% was a reasonable expectation for the 4Fg loads. The British had used very fine grained BP in their .303 without any problems.

Even though the available evidence suggested that moderate 4Fg loads would be safe, I started low with a strong Siamese Mauser chambered in 45-70 and then worked up slowly. I also used a Mauser chambered in 375 H&H, the poor man's 38-90. After the 45-70 and 375 H&H 4Fg loads were found safe, 40-82 loads were tested in a C. Sharps 1875 action. The C. Sharps 1875 is a modern made replica that is at least as stout as an 1885 Winchester High Wall, and Winchester used standard Highwall actions for the pressure test guns in their laboratory.

I used CCI pistol primers for the 4Fg loads because those primers were made of lighter gauge metal than rifle primers and were reputed to show pressure signs at just 35,000 psi.

No one else was endangered during these tests because I tested the 4Fg loads on a weekday afternoon when I was the only one shooting at the range. No one else was there except for the range safety officer.

The 4Fg loads fired in the 45-70 and 375 H&H Mausers did not produce any excessive pressure signs or primer flattening. Also, the first 4Fg rounds fired from the 40-82 showed no signs of excessive pressure. Thus it was a surprise when I opened the 1875 action and found that the primer pocket had expanded. It turned out that the 40-82 pressures had skyrocketed because that particular cartridge case had been trimmed too long. Firing stretched it into the throat, tapering the case down onto the bullet and making it difficult for the bullet to be released from the case.

Of course, if a bullet doesn't move out quickly, the pressure goes way up. Given the excessive length of that cartridge case, pressures would have zoomed up if I had loaded the cartridge with 2Fg or 3FG. Powder granulation had nothing to do with that excessive pressure peak. It was a function of delayed bullet release.

Of course, all this was explained in the posts on the GOEX and MSN sites. Selectively quoting from these posts only gives an inaccurate picture of what actually transpired, and does a disservice to BP shooters who are looking for accurate information.

As I hope I made clear, I am not advocating the use of 4Fg in BP cartridge rifles. As my experience with the 40-82 shows, you have to pay attention to every aspect of handloading, including case length.

Just to set the record straight, I have no beef with Spencer Wolfe, Lyman Products, or Accurate Powder. Nor do I have a beef with anyone who made a constructive response to this inquiry. I'm not trying to supercharge black powder cartridge rifles. Those 4Fg loads only increased muzzle velocities by about 50 fps compared to the 3Fg loads. If anyone wants high velocity, they should try another game than BPCR.

Despite all the above safety precautions mentioned above, I do not recommend that anyone use 4Fg in a BP cartridge rifle.

In conclusion, it's real simple. I'm looking for lab tested data on pressure generated by BP cartridge rifles. If anyone has such data, or knows where I can find it, I'd like to learn more.

All the best,

Dick Gunn

Mr. G, good of you to drop in! First off, just so you know we're on level ground, there is absolutely no doubt that I'm over the edge in the insanity department...don't worry too much about how others perceive you, it'll just slow ya down.

Next, rest assured that most of us have reliable short term memory...maybe you were quoting us just to build up a good head of steam, but it weren't required.

You say you were looking for data points on which to build an equation to estimate BP pressures??? Trusting that you used some form of pressure measuring equipment and have results would you be disposed to share that or have we just pizzed ya off to the point of no return?

I have questions and comments. I found the comments about the .40-82 as indicated, during a Google search about BP pressures. It is clear that it is your verbiage...like I said, I didn't know what it meant, just what I read. There seems a derth of info regarding the subject of BP pressures, my quest more aligned with the idea of building a slug gun and with the issue raised by another it seemed prudent to explore that world. The stars aligned I suppose.

I'm left to wonder why one would be inclined to explore pressures using ffffg, or why you did. You even suggest that others not use it for loading BPCRs so I miss the point. Not being snide, I probably wouldn't get it if you were talking canon grade BP either. Anyway, all that said, one last question with preamble: It sounds as if you're looking to create something akin to a BP Powley Computer, if not in the same form, at least for the same general purpose. If that is so I'm sure that somebody somewhere has already been there. Perhaps the folks at Aberdeen could point you in the right direction...or Goex/KiK/etc, etc. If that is the case why would you want data on something you don't recommend yourself?

A comment in parting from this post, hopefully not the last discourse between us. Do be more careful about case trim length. I understand how you had your pressure excursion after reading your explanation...didn't see that association when I Googled up the info I 'quoted' above. Anyhoo, case trim is as basic as it gets when reloading and if you're looking for data(reliable) you need to embrace the concept of perfect mastery of details or it's garbage in/garbage out.

My .02 worth sir, hold into the wind.

Dan;

Thank you for your response.

When I was performing those notorious 4Fg tests, I was measuring muzzle velocity, not pressure. That led to some nice equations for estimating BP muzzle velocities. Now I'm interested in pressure, a different animal. The first step in investigating BPCR pressure is to see what others have published.

Unfortunately, there has been relatively little information published about the pressures generated by BP cartridges. Perhaps this is because no one much cares. After all, modern breech loading rifles of strong design are much stronger than needed for the relatively low pressures generated by BP, so there's no particular safety problem to investigate. While smokeless powder can potentially generate pressure spikes in excess of 200,000 psi, BP is limited to a maximum pressure of about 86,000 psi. This maximum pressure of 86,000 psi was determined by British captains Noble and Able using a pressure vessel which did not release any of the BP combustion gases.

Modern breech loading rifles of strong design should be able to withstand pressures well in excess of 86,000 psi. A proof load typically produces a pressure that is 30% over a cartridge's normal maximum pressure. Some modern smokeless cartridges can generate peak pressures of 65,000 to 70,000 psi in their normal loadings, which translates into about 55,000 cup. That means the rifles firing these cartridges must be able to withstand a proof load of 90,000 psi.

Since these strong, modern rifles are routinely operating at pressures near the maximum that can possibly be generated with BP, it seems like nobody particularly cares how much pressure a BP cartridge could generate because they expect it will probably be within a modern rifle's margin of safety. Of course, we've all heard of rifles that have blown up for one reason or another. Bore obstructions are a major culprit, also defects in the barrel steel, loading the wrong cartridge in the rifle, etc., etc.

I'm interested in BP pressure because of the way it affects bullet design. If a bullet's unsupported nose is too long, or the alloy is too soft, or the base pressure is too high, the nose may slump and bend the bullet out of shape, causing yawing and inaccuracy. If I can estimate the pressure that will be generated by a particular load of BP, it will help in the bullet design process. Right now, I just want to work up some pressure estimating equations that I can include in my bullet design spreadsheet.

You wrote, "It sounds as if you're looking to create something akin to a BP Powley Computer, if not in the same form, at least for the same general purpose. If that is so I'm sure that somebody somewhere has already been there. Perhaps the folks at Aberdeen could point you in the right direction ...or Goex/ KiK/ etc., etc. If that is the case why would you want data on something you don't recommend yourself?"

A Powley computer for BP? A great idea, but probably beyond my skills. If there is something like that out there, I haven't been able to find it. I've talked to a few folks associated with Aberdeen, and they say they haven't got any information on this topic or, if their lab does have it somewhere, they don't know anything about it and cannot find it. My reason for posting on the GOEX board was in hopes that someone associated with GOEX would step forward with lab tested pressure data, but that hasn't happened yet. Does KIK have a similar board where inquiries could be made?

I don't recommend the use of 4Fg in BPCR rifles for several reasons. Number 1, nobody I know has done any pressure measurements to prove it is actually safe. Theory says it may be, but theory and reality are two different things, and I am not going to recommend anything that I think may be questionable or unproven. Number 2, the powder manufacturers do not recommend it, and their lawyers must know something. Number 3, 4Fg does not give a particularly useful increase in muzzle velocity or a decrease in fouling as compared to 3Fg. Number 4, increased pressure beats the heck out of bullets and forces you to use high drag blunt nosed bullets to prevent nose slumping . Number 5, this is an open forum, and inexperienced shooters could possibly read this stuff and get themselves into trouble. Hence I do not recommend the use of 4Fg powder in BP cartridges. This chronicle of my researches is presented for informational purposes only.

You asked about the sharing of pressure data. I haven't done any pressure measurements myself, other than examining primers for signs of overpressure. Therefore I haven't any pressure data to share.

Regarding the gathering of pressure data with strain gauge equipment, there are some problems associated with the potential accuracy of home style pressure measuring equipment This was discussed earlier on the GOEX board. Oehler makes, or used to make, a fine hobbyist rig for measuring barrel strain. Others make some similar but less sophisticated strain measuring equipment. However, none of this strain gauge equipment is as accurate as a calibrated piezoelectric transducer setup on a pressure gun. Oehler specifically says its hobbyist unit can not be relied upon to generate absolute psi values.

Hobbyist strain gauge equipment can compare loads fired at a given range session but, even for cartridges for which standardized SAAMI pressure test ammo is available, there are too many variables involved to make any claims for true pressure calibration. Regardless, there is no standardized SAAMI pressure test ammo available for BP cartridges.

Oehler says you have to glue the strain gauges to the barrel and that means, at a minimum, removing the bluing over the chamber, and maybe hogging out the stock to fit the gauge. Now, someone else might want to jump right in and do this and spend $500 or more, but I'd like to start out by inquiring whether or not someone else has already done it, and would be willing to share their results.

You said you had read some of my verbiage about the 40-82 by Googling some earlier posts on other sites, but you still had questions. Also you said I did not have to quote earlier posts because you guys had good short term memory. I quoted some of the preceding posts in this string so that anyone else who might Google up this topic or my responses would get a full picture and would see that I was not making this stuff up.

You asked if I was pissed off. No, I am not pissed off, just disappointed that an honest effort to further our understanding of BPCR performance has been misunderstood and/or misrepresented by some.

You wrote, "Case trim is as basic as it gets when reloading and if you're looking for data (reliable) you need to embrace the concept of perfect mastery of details or it's garbage in/garbage out."

Absolutely agreed.

So, it's real simple. I'm looking for lab tested data on pressure generated by BP cartridge rifles. Can anyone help with this search?

All the best,

Dick Gunn

RGunn I still believe you to be bull headed. I find serious fault with your reasoning about the pressure testing equipment available to the general public. I also would still be quite leary about having to shoot a BPCR match with in a couple hundred feet of you and your rifle, and wouldn't have a whole lot of qualms telling you this all face to face just as I have here.
Safety is of major importance in the shooting sports, and it looks to me much as tho you have pitched all common sense about reloading with black powder right down the drain.
You stated this subject was discussed at length on the Goex board, while I haven't looked there in a few days, your idea of discussed at length and mine run seriously afoul of each other.
There is a thread under the ask the gunwriters section of this board about the RSI pressure system , and contained with in the same thread is also some good information on the Oehler system. While YOU might think such systems to be "questionable", myself I find them much more reliable, than the haphazard approach you've taken to loading blackpowder in cartridges.

I am befuddled. Posted a response and it vanished into thin air. <img src="/ubbthreads/images/graemlins/confused.gif" alt="" />

Walking down the exploration road myself but in more mundane ways, mostly concerned that I don't wind up re-cocking the lock from vented pressure and the attendant hazards of stuff splattering my face whilst shooting a slug gun and hoping to duplicate BPCR velocities, or as least come close in the .40-.45 bore with 500ish grain boolits.

Well, that said there is a fella named Sherman Bell published frequently in Double Gun Journal who uses Oehler equipment in good fashion with BP and low pressure Le Smoke loads in scatterguns...mostly. What he does is...

Have his loads tested in a piezo pressure gun and then uses them to calibrate his test equipment, and vice versa...sorta like two way verification. He uses a NEF break action 12 for his testing and I believe he has settled the issues related to differences in chamber dimensions and effects of chokes. He not only tests chamber pressure but has attached sensors in short interval to verify/examine the curve as the shot rambles down the tube. All in all the results are that he has developed nitro for black loads that he uses in damascus guns that actually give the same velocity at less pressure and with a similar curve. Point of consideration with the strain gauge system is that it is alleged to give poor results with thick walled chambers/barrels at low pressure levels. Apparently this is not an issue with shotgun barrels. I presume it would be easy enough to calculate a minimum safe wall thickness for a give rifle cartridge though that is only speculation. The NEF would be a dandy if that approach were taken...I'd use a block house or an empty range and a long string...

I have also read in several different sources that the Naval Ordnance Board used BP to generate pressures in excess of 100KPSI some years prior to WWII though I've not seen documentation to that effect.

I think you're right regarding the lack of info on BP pressures and have no inside info regarding that subject or forum boards where it may be discussed. That said it is obvious that there are thresholds not clearly defined by manufacturers and SAAMI. The scattering of different recommended BP loadings from gun builders in phenomenal, from 90 to 180 grains, using conicals or RBs. I've read of fella using 600 grain bullet with 180 grains as a working load in .58 caliber in Africa to no ill effect(except on the quarry).

My suggestion would be to contact Mr. Bell thru DGJ...if anybody knows he would, at least a source of some info or technology...something. A second possibility would be to contact the web master at http://www.eskimo.com/~jbm/ . I've had a couple of email chats with him and seen him on a few boards over the last few years. He knew Robert McCoy personally and that would indicate more than passing knowledge of the issue of ballistics. My .02 worth on that matter.

I note that many if not most BP guns from days gone by have rather thin barrels, an exception being styles common to today's BPCR rifles and of course old double rifles. It says a lot about the pressures involved...or the fashion of the day.

Ranch13;

Thank you for your response. Please tell me, what is the serious fault you find in my reasoning about the pressure test equipment available to the general public?

I simply pointed out the limitations of current strain gauge pressure test equipment, as enumerated by Ken Oehler and others. While strain gauge equipment is much better at estimating chamber pressures than such techniques as judging sticky extraction, miking cartridge base expansion, or eyeballing primers, and we are fortunate to have it available at a price less than a new rifle, it is not as accurate as a calibrated laboratory piezoelectric transducer system.

I read the entire Gunwriters' thread about the strain gauge systems several weeks ago and found nothing there that contradicts either the opinions or facts that I've expressed in these posts. As I said before, I am just looking for accurate pressure data concerning BP cartridges. Pressure measured in a climate controlled laboratory with calibrated equipment is almost certainly more accurate and more reliable than pressure measured with an uncalibrated strain gauge at an outdoor range.

Perhaps you are confusing reliability with accuracy. A measuring system may be reliable and it may give consistently repeatable results, but that does not mean it is accurate. A BPCR strain gauge system, pretty much by definition, cannot be properly calibrated. There is no SAAMI calibration ammunition for black powder cartridges. Without proper calibration, there is no guarantee of accuracy.

If a measuring system is poorly calibrated, and you have no other frame of reference, every measurement it makes could be consistently off by 30% or more, and you would have no way to know it. That's why data from a laboratory calibrated pressure measuring system is preferable to something that you just glued onto your gun. Unfortunately, the laboratory setup costs a heck of a lot more, either to buy or to rent.

If anyone has data obtained with a strain gauge system and would be willing to share it, I would be very happy to receive it. Any data is valuable where none was previously available.

You said you would be quite leery about having to shoot a BPCR match within a couple hundred feet of me and my rifle. You wrote, "Safety is of major importance in the shooting sports, and it looks to me much as tho you have pitched all common sense about reloading with black powder right down the drain."

Seems to me everything I've said thus far is sensible. Safety is always paramount. I thought I'd made it clear that 4Fg loads, safe or not, fall in the area of experimental loads, and in my opinion should not be used at a match or in any venue where other shooters might be placed at risk. What have I said that makes you think I would violate such an obvious concept by taking useless 4Fg loads to a match?

You also referenced the "haphazard approach" I'd taken to loading black powder in cartridges.

In the previous posts, I outlined the graduated procedures that I used in my experimental test series. This was not "haphazard" in any sense of the word that I understand. Given all the cautions and caveats I expressed, given the lack of any overpressure signs with loads using CCI pistol primers that flatten at 35,000 psi, given the strength of the modern bolt action rifles employed, and given the known maximum pressure limit that can be generated with black powder, it seems to me that common sense was well exercised in this test series.

In conclusion, all the objections you've raised were addressed in the thread on the GOEX board and in the posts on this board. Except for one overpressure incident due to an excessively long cartridge case, no overpressure signs were seen with any of the other 4Fg loads discussed. My experimental velocity protocol was concluded safely and without damage or danger to anyone or anything.

Am I bullheaded? Maybe so. My wife would certainly agree with you on that point. But I simply feel that I am stating plain and obvious facts.

There is very little good pressure data for BP cartridges. 4Fg produces enough additional pressure that, in my opinion, it should not be used in BP cartridges. The velocity and fouling gains with 4Fg are negligible.

As you can see, I agree with you on all points of safety and suitability. We just disagree about my common sense in performing this experimental series in the first place.

All the best,

Dick Gunn
a.k.a. Dr. Gunn

Dan;

Thank you for the information about Mr. Bell. He obviously appreciates the importance of calibration. I'll try to contact him.

Brad Millard runs the jbm site. He and I have swapped a few insights and reminiscences about Bob McCoy. Bob's premature passing was a real loss to the ballistics community.

Like yourself, I have seen some authors refer to an alleged naval test of BP that produced higher pressures than 86,000 psi. When contacted, one of those authors said he found the naval BP pressure info in Dr. Tenney L. Davis' book The Chemistry of Powder and Explosives. I got a copy of that book. It's very comprehensive and has a lot of information about BP chemistry. But I could not find any reference in it to BP pressures.

In the period before and after WW1, the military services were experimenting with many different propellants, some smokeless, and some based on BP. One kind of powder called brown powder was a BP based on, I recall. a coconut shell charcoal. It produced significantly more pressure than traditional black powder. Also, there were several nitrated semismokeless formulations which tended to generate very high pressures if improperly handled. Black powder is still in use as an igniter for artillery pieces, but I'd be moderately surprised to learn that straight BP was used for combat in naval guns after WW1.

Cheers,

Dick

Dan;

A postscript.

After WWI the army used a railroad gun at Aberdeen to test the fusing of aerial bombs. They'd put the bomb in a sabot and shoot it horizontally at a solid target. A charge of BP in the railroad gun gave the bomb the same terminal velocity as it would have achieved if they'd dropped it from an airplane, with much less expense, greater accuracy on target, and a faster turn around time between tests.

Dick

Ya think they'd let that one in a Quigley match? <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />

RGunn I'm befuddled at how you refuse to accept the findings from different sources. If you have been paying any attention over your long and studious reloading career you surely would have noticed by now that no two outfits data will completely agree.
Until now you have said little if anything that I've seen about how you "worked" into that almost suicidal charge. You also let on that you've well versed in reloading , so it seems to me that you would know that a case that was a little long isn't to likely to pop primer pockets, unless you were already way over the top on pressure. Also I suspect you had to fire that charge or something similar multiple times to get a 40-82 case to stretch enough that it could become dangerous. It could of been that that case stretched as well as blew the primer with that dangerous overload you had stuffed into it. As I've said before that you didn't lose any body parts is certainly a testiment to the quality of that CSharps.
I also can't understand why you won't take SAAMI's pressure specs on cartridges as proof of how much pressure blackpowder and cartridges generate. The 45-70 (Trapdoor) is set at 28000 psi, I would expect that's probably what would be when loaded with a 500 gr bullet and 70 grs of 3ff. 2f loads will likely be a bit less, another example is the 38-55 it specs at 30,000 cup.
As the old Ideal manual stated it's hard to get into trouble when using the PROPER granulation of black powder.

It's hard to get into trouble period, if you stick with the manuals. Black powder is black powder. If it were meant to go faster...they'd invent 777! Are we talking about a gamesman trying to have an edge on the 500 yard line? If it's just to hunt game, then everything you need to know about black powder granulation was learned by 1880!

Dan

Dan I'm at a loss as to what would ever make someone want to put that much 4f in that primed cartridge, seat a bullet and then actually fire the thing, and then proceed to call all the existing data, and suggestions of where to go and what to do to get pressure data, "questionable" "suspect" and "unreliable".
<img src="/ubbthreads/images/graemlins/crazy.gif" alt="" />

Dear Ranch13;

I am sorry to learn that you are still befuddled. I am doing my level best to unfuddle you. Let's take your questions and observations point by point.

Despite your assertion that I am unwilling to accept findings from different sources, I am perfectly willing to accept such findings. Haven't I been requesting that folks tell me of any information they might know of concerning BP cartridge pressures, including pressures measured with strain gauge setups?

You ask have I, "Noticed by now that no two outfits data will completely agree." Yes, of course. That was the whole point of my initial request for information and of all the ensuing discussion. The BP cartridge pressure data provided by Accurate, Lyman, and Spencer Wolfe differs by at least 10%. While this is pretty close, the data from the different outfits obviously does not completely agree. Probably, if it all agreed, we would not even be having this discussion.

You wrote, "Until now you have said little if anything that I've seen about how you 'worked' into that almost suicidal charge."

There are two points here: my research method, and the alleged suicidal nature of the 40-82 charge. I apologize if I had not made my research method clear to you in my initial posts. I did not realize it would become such a bone of contention. The use of graduated charges and close observation for undue pressure signs seemed like such an obvious protocol that I did not explain it in detail in the initial posts. Clearly, the use of graduated charges and modern bolt action rifles capable of containing 150,000 psi of pressure or more was completely safe when considering a charge whose maximum pressure could not exceed 86,000 psi. Just compare the numbers.

Regarding the 'suicidal' nature of the 40-82 charge, it may seem like splitting hairs, but the problem there was not the charge of 4Fg. It was the cartridge case length. As noted in an earlier post, that particular cartridge would probably have generated similarly high pressures if I had loaded it with 2Fg or 3Fg. If a bullet is trapped in the case by a case mouth crimped into the throat, the propellant gases have nowhere to go and pressure builds in the chamber. Fortunately, with BP you are limited to a maximum pressure of 86,000 psi. Hence firing such a cartridge in a suitably strong firearm should not be construed as evidence of suicidal proclivities. If the firearm can safely contain 150,000 psi, a load of 86,000 psi should not be fatal to anyone standing behind the muzzle.

You wrote, "You also let on that you've well versed in reloading. It seems to me that you would know that a case that was a little long isn't to likely to pop primer pockets, unless you were already way over the top on pressure. Also I suspect you had to fire that charge or something similar multiple times to get a 40-82 case to stretch enough that it could become dangerous."

It's true that I'd had a lot of handloading experience prior to that 40-82 overpressure incident. But most of that was with smokeless, and I was still learning the quirks of BP. BP is different from smokeless in several respects. One is its proclivity for causing case stretching, especially in new cases. Unlike the rounded grains of smokeless, grains of BP tend to be more sharp cornered. When BP is fired, the forward part of the powder charge is temporarily compressed and squeezed outwards against the case walls. Those sharp cornered BP grains press into the wall of the case, especially near the neck, and as they are propelled forwards they tend to drag the case along and stretch it towards the throat.

This phenomenon is more common in the longer express cases like the 40-82. Older cases which are work hardened are less susceptible to such neck stretching than new cases. Older cases stretch more near the base. When I did that series of 4Fg experiments 10 yeas ago, I was using new cases. Stretching a primer pocket in a solid headed rimmed case requires a lot of pressure, right up near the 86,000 psi maximum that can be generated with BP.

You wrote, "It could of been that that case stretched as well as blew the primer with that dangerous overload you had stuffed into it."

Well, anything is possible, but BP is noted for its consistency of ignition. That's why we can get such low SDs in our muzzle velocities. Remember, that load of 82 grains of 4Fg was not inherently dangerous in that situation because it could not generate more than 86,000 psi and it was being fired in a modern rifle that could easily contain 150,000 psi.

Before firing the 40-82 which over stretched in the chamber, I'd fired four other 40-82s with the same load of 4Fg, all without any signs of excessive pressure. Recall, I was using the CCI pistol primers whose thin cups were then reputed to show pressure signs at just 35,000 psi. I'd fired five rounds of 45-70-500 4Fg with no adverse pressure signs. I'd fired five rounds of 38-90 4Fg (375 H&H) with no adverse pressure signs. I'd fired four rounds of 40-82 4Fg with no adverse pressure signs.

Then, on the fifth round of 40-82, the primer pocket was loosened and the muzzle velocity jumped 100 fps. When that cartridge case was extracted, the case had lengthened and the case mouth had tapered in as if it had been crimped. But I had been loading without any crimp. None of the other fired 40-82 cases showed any tapering of the case mouth. All those other cartridge cases were still of normal length.

It seems to me that, if fourteen cartridges had been fired without any signs of overpressure or case mouth tapering, and then one cartridge with an identical load showed an increased length, a tapered case mouth, and a dramatic overpressure, the previous fourteen loads were probably not dangerous, and something other than the amount or granulation of the powder was responsible for the excessive pressure of the fifteenth round.

You wrote, "As I've said before that you didn't lose any body parts is certainly a testiment to the quality of that Csharps."

Yes, the C. Sharps 1875 action is very strong, probably at least as strong as a Winchester Highwall. That's one of the reasons why I felt it safe to fire a cartridge that could potentially generate as much pressure as 86,000 psi. I certainly would not have wanted to fire such cartridge in a Ballard or a Stevens 44 or a Maynard. Even a replica made of modern steel could be unsafe at this pressure if the action design is weak. I recall, when Red Willow first introduced their Ballard replicas, I asked one of their guys about the strength of the new actions. He said they were very strong. He said they had chambered one in 44 Magnum and fired a proof load. He said the barrel and the receiver did not burst, but the breech block did bend. Frankly, this is not my idea of a strong action.

You wrote, "I also can't understand why you won't take SAAMI's pressure specs on cartridges as proof of how much pressure blackpowder and cartridges generate. The 45-70 (Trapdoor) is set at 28000 psi, I would expect that's probably what would be when loaded with a 500 gr bullet and 70 grs of 3ff. 2f loads will likely be a bit less, another example is the 38-55 it specs at 30,000 cup."

I'm happy to accept SAAMI specs as the maximum pressure allowable for black powder arms. But a SAAMI spec is not necessarily based on the maximum pressure anticipated with BP. I don't know what data SAAMI's 38-55 pressure limit of 30,000 psi is based on, but I suspect it must be a later high speed smokeless load intended for the Winchester 1894. It seems unlikely that 55 grains of 3Fg and a 330 grain bullet could produce 30,000 psi.

We can agree that SAAMI's 45-70 max. of 28,000 psi is probably based on a 70 grain load of 3Fg and a 500 gain bullet. The 45-70-500 3Fg is one of the few BP cartridges for which good, lab tested pressure information has been published. Spencer Wolfe wrote, "The M1881 bullet (500 grain) loaded with 70.0 grains of 3Fg gave a velocity of 1315 fps with an average pressure of 25,800 cup - 29,600 cup peak (per HP white labs). The Arsenal listed an average pressure of 25,000 psi for this load.... SAAMI gives the average maximum pressure for any cartridge fired in the 45-70 as 28,000 cup with 31,200 cup absolute individual peak."

Unfortunately, there are no SAAMI specs for many of the BP cartridges that we fire every day in competition. No one is saying that a 45 2 7/8 loaded with 2Fg is unsafe in a modern replica rifle, but it would still be nice to be able to estimate the amount of pressure being generated.

You wrote, "As the old Ideal manual stated it's hard to get into trouble when using the PROPER granulation of black powder."

True, but even here there is a difference of opinion about what is proper. Spencer Wolfe noted that different 19th century BP manufacturers used different standards for grading the size of BP grains. He says he made little progress duplicating the ballistic performance of Arsenal 45-70 rounds until he realized that the 1Fg referred to in the old records was the equivalent in grain size to today's GOEX 2Fg.

There's a lot about BP that used to be known but has been forgotten. Now we are testing and rediscovering stuff.
I am not bringing this information to your attention so that you will repeat my overpressure experience. I want people to avoid 4Fg as a primary charge in BP cartridges. I am discussing this matter as a cautionary tale.

I do not condone the use of 4Fg as the primary charge in BP cartridges.

Besides the risk of the unknown, there are some practical considerations. Successful BP bullets require a moderately soft alloy to cope with bore irregularities caused by fouling. The pressures generated by 4Fg are higher than 2Fg and 3Fg and therefore require harder alloys or shorter bullet noses to prevent nose slumping and inaccuracy. I believe that any slight velocity advantage that might be obtained with 4Fg is more than offset by the blunt nosed, high drag bullets that must be employed with it and the necessary use of hard alloys which cope poorly with BP fouling.

Ranch13, I apologize for going on at such length, but your persistence in asking these questions and making these observations indicates that you have a genuine desire to understand this stuff. Therefore it only seemed right to address your questions and observations in a point by point manner. Thank you for your continuing interest in this topic.

To conclude, I'm looking for lab tested data on pressure generated by BP cartridge rifles. Can anyone help with this search?

All the best,

Dick Gunn

Dan Chamberlain wrote, "It's hard to get into trouble period, if you stick with the manuals. ....Are we talking about a gamesman trying to have an edge on the 500 yard line? If it's just to hunt game, then everything you need to know about black powder granulation was learned by 1880!"

No argument, the manuals are supposed to give you safe information. But what about the topics which are not addressed in the manuals? If you want to expand the bounds of knowledge, you need to do experiments and, of course, those experiments should be done in a safe manner.

If you have read the earlier posts in this thread, you will know that we are not talking about gamesmen who are seeking an advantage at the 500 yard line. We are talking about folks who are sincerely committed to black powder research on a limited budget.

While it's probably true that everything we need to know about black powder granulation was learned by 1880, unfortunately a lot of that information has either been lost since or has been held as a closely guarded "trade secret." Open exchange of information is one of the nice things about forums like this, with shooters freely sharing their experiences and discussing what did or did not work so that other shooters may benefit.

All the best,

Dick

Finer grades of BP also seem to produce more soot and fouling. Most powdermakers recommend 2f for cartridges 40cal and up. and percussion guns can use 3f or 2f , again , depending on caliber. An old-timer who casts my bullets suggested I mix 2f and 3f for my cartridges. Seems to be what GOEX did with their new 'cartridge' grade.

Although I was educated as a scientist, and can appreciate and respect rigorous research, this topic just makes my head hurt! I think I'll just go do something that can have an effect on my scores, like load up some Swiss 1.5, stuff some Paul Jones Creedmoors, and go to the range to practice my hold and trigger squeeze, and wind doping.

Paul

Dick;

Much of the load data of yesteryear is actually based on powders that were probably of finer quality and finer granulation than we have today. Ross Seyfried uses 3f in his 12ga shotguns because his research has concluded that today's 3f is similar in granulation and energy to yesteryears 2f. His research suggested that many successful shotgunners of the 1800s were using healthy charges of 3f in shotguns with Damacus twist barrels without ill effects and that 3f in those days was similar in granualation and energy to what we call 4f today!

The guy who founded Navy Arms killed elephants with .58 caliber Hawken rifles made by Investarms with 180 grains of either 2f or 3f (I can't recall the granulation) and cape buffalo with a .58 caliber Zouave carbine style rifle using 160 grain powder loads.

The problem with black powder as I see it, is it does not have the same pressure curve as smokeless and that the explosive force of black powder has different effects on the strength of the steel than does smokeless. Whereas, smokeless loads will give hints of over pressure, black powder is not so considerate and damage can result with no outward signs that one is stressing the firearm. I may be wrong, as this is something I believe Sam Fadala had researched and tested.

What exactly is your aim? We know from Winchester's testing of the "76" that even that weak action can withstand incredible...almost unbelievable stresses and continue to function, but other than ruining a perfectly good 76, all I learned from their testing is that they built a gun that wouldn't fall appart the first time it was overloaded, but the ballistics and terminal energies couldn't appreciably be improved on.

Dan

Ranch13;

Now I am perplexed and a little befuddled. You keep misrepresenting what I have written, and it makes me wonder if you are genuinely confused on this topic or if you are just pulling the leg of the newest tenderfoot on the list?

You wrote, "I'm at a loss as to what would ever make someone want to put that much 4f in that primed cartridge, seat a bullet and then actually fire the thing."

I thought we had gone over this pretty thoroughly. There was a need to learn the muzzle velocities produced by moderate loads of 4Fg BP, a topic that had not been addressed in any of the manuals, and a procedure that had not been in general use since the world's military establishments all transitioned from BP to smokeless powder. A safe and rational test protocol was devised and implemented. Even though there was one unexpected over pressure experience, the safety margins built into the test protocol assured that no one, including myself, was in any danger. Is there any way I can say this more plainly?

You also said that you were at a loss as to why someone would, "then proceed to call all the existing data, and suggestions of where to go and what to do to get pressure data, 'questionable' 'suspect' and 'unreliable'."

Now you are putting words in my mouth. I have not called all the existing data questionable, suspect, or unreliable.

While there are certainly modest discrepancies between the BP pressures published in various sources, the collective results are fairly close. Accurate's published BP cartridge pressure data does run about 10% higher than Lyman's. This is a simple and incontrovertible statement. Just look at their respective publications and you can see for yourself.

To pick a nit, I used the word "questionable" only in the following context. I'd written, "I don't recommend the use of 4Fg in BPCR rifles for several reasons. Number 1, nobody I know has done any pressure measurements to prove it is actually safe. Theory says it may be, but theory and reality are two different things, and I am not going to recommend anything that I think may be questionable or unproven." That means, the potential safety of 4Fg loads is questionable because no one that I know of has done any pressure testing on 4Fg cartridge loads, other than my observations of the normal primer appearance and muzzle velocities generated by fourteen 4Fg loads.

Similarly, doing a word search on my entries for the GOEX and Campfire boards, I did not call any pressure data "suspect." In the thread on the GOEX board, I'd written only, "I suspect that some BP cartridges may be running higher pressures than a lot of us realize." In all my posts on the Campfire board, I used the word "suspect" in only the following context. "I don't know what data SAAMI's 38-55 pressure limit of 30,000 psi is based on, but I suspect it must be a later high speed smokeless load intended for the Winchester 1894."

Also, I did not use the word "unreliable" on either the GOEX or the Campfire boards. I did talk about the concept of reliability or precision vs. accuracy, saying only that calibrated lab piezoelectric pressure test equipment was probably both more accurate and more precise or reliable than hobbyist strain gauge equipment.

Finally, I did not denigrate any suggestions offered as to where to go and what to do to get pressure data. Some folks offered suggestions about Pyrodex data but unfortunately Pyrodex does not produce the same pressure curve as BP. Others suggested sources that I had already tried, and I thanked everyone who made a constructive contribution to this discussion.

If you as a Campfire Ranger are just pulling my leg in hopes of continuing this useful discussion, then your efforts have been rewarded. I hope the information provided in these posts has been helpful to other shooters.

If you are still confused about this topic, then please say so without any additional and unhelpful personal invective or misrepresentations, and I will try to speak more plainly. We can have a useful conversation based on a difference of opinion concerning observed facts, but we will not get to any truths by behaving in an intemperate or impolitic manner.

All the best,

Dick

Dan Chamberlain asked, "What exactly is your aim?"

I'm looking for lab tested pressure data on BP cartridges that I can use to work up an equation for predicting BP pressures that I can then include in my bullet design program.

Dan wrote, "The problem with black powder as I see it, is it does not have the same pressure curve as smokeless."

Yes. Because of these differences, equations that are useful for predicting smokeless pressures do not work very well for BP. In a rifle barrel, BP combustion products do not behave exactly like an ideal gas.

Dan wrote, "Much of the load data of yesteryear is actually based on powders that were probably of finer quality and finer granulation than we have today. Ross Seyfried uses 3f in his 12 gauge shotguns because his research has concluded that today's 3f is similar in granulation and energy to yesteryears 2f."

In the 19th century, there were probably as many varieties of BP available to shooters as there now are of smokeless. The burning and pressure characteristics of BP for small arms can be varied in three ways: composition, compression, and grain size. Powder for cannons could also be varied in grain shape.

Composition basically means how much fuel, i.e. charcoal and sulfur, and how much oxidizer, i.e. potassium nitrate, are in the BP. Typical small arms powders have 75% potassium nitrate, 15% charcoal, and 10% sulfur. Less sulfur makes the BP harder to ignite and lowers the peak pressure. Less nitrate saves money but makes the BP dirtier burning and more prone to fouling. Some charcoals, like willow or alder distilled at low temperatures, produce a more powerful and cleaner burning BP than hardwood charcoals distilled at high temperatures. This low temperature charcoal is or was supposedly the secret to Swiss powder before the Swiss plant blew up and production was shifted to Wano in Germany.

Compression mostly means how long the powder was wheel milled and how densely the press cake was compressed during manufacture. The denser the powder, the more strongly the constituents of a given grain hang together, and the longer it takes for a flame to propagate from the surface of a grain to the center. More grain compression means slower burning. There are basically four grades of compression: cannon, musket, rifle, and sporting or shotgun. Elephant powder was compressed at a level about like musket powder, GOEX like rifle powder, and Swiss like sporting powder. That means, a given amount of 3Fg Elephant would produce about the same pressure as the same amount of 2Fg GOEX or 1Fg Swiss.

Grain size also influences burning rate. The smaller the grains, the greater the available surface area within a given mass of powder. More grain surface area means more rapid consumption of the powder. 2Fg on average has about 40% more surface area than 1Fg and 3Fg has about 40% more surface area than 2Fg. 4Fg is supposed to have about 40% more surface area than 3Fg, but some manufacturers include their fines in the 4Fg mix, so some brands of 4Fg may burn more rapidly than others.

When Ross Seyfried found that he needed to use 3Fg powder to duplicate the ballistics of 19th century 2Fg powder, perhaps he was using modern rifle grade GOEX to duplicate the performance of a less heavily compressed 19th century 2Fg sporting powder?

mkk41 wrote, "Finer grades of BP also seem to produce more soot and fouling."

When BP is manufactured, one of the last steps is polishing, and that sometimes includes coating of the grains with additional carbon to protect them from moisture and static electric charges. As grain size becomes smaller, the carbon coating on the outside becomes an increasingly larger percentage of the BP's total composition. If you add too much carbon to the outside, there is too much fuel, and the powder will burn dirtier with excessive fouling. That's one reason why some modern powders burn dirtier in the smaller grain sizes.

The best BP produced in the 19th century did not rely on an extra coating of carbon for protection from the elements. Instead, a thin glaze of potassium nitrate was sweated out of the grains during tumbling to form a protective capsule around each grain. Of course, this was an extra step in manufacturing, and it made the powder more expensive.

Dan, can you please tell me where I may learn more about the Winchester pressure tests on the model 76 and the BP shotgun tests run by Ross Seyfried?

All the best,

Dick

Dick;

Ya'll will have to do a little searching, but I'll get you pointed in the right direction. If you google "black powder shotgunning" you will undoubtedly find the Seyfried article...and a good one it is. Also, if you do a similar search for the winchester 76 you will have to sift through a few articles, but you will no doubt find the one that lists the different things Winchester did to prove the toggle link action was far stonger than people gave it credit for.

I wish I could post links, but these searches were some time back, though I read the articles this year so they should still be available.

Dan