Home Forums Hunting & Shooting Ask The Gunwriters Lever gun pressure?

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What are we going to see in a 30-30 lever gun to indicate excessive pressure? A sticky bolt? Takes over 65,00 PSI. Cratering of primers? Lose primer pockets? Case head expansion? Brass flow into extractor? We talk about "working up" but what are we going to see that indicates high pressure at only 40,000 PSI? If I blow a primer in my bolt gun I know that I am over 70,000 PSI and well into the danger zone. If I blow a primer in a lever gun, I assume it would take similar pressure levels to blow a primer, my gun would be in the scrap metal zone as in grenade.

So what am I looking for to indicate excessive pressure in a good tight lever gun? Case head measurement? According to Ken Waters that is a good indicator but only for matching factory loads. So what about modern lever guns and cartridges? The 45-70 and 35 Rem are well underloaded by the factory for use in weaker old guns. So how do we know when we are approaching safe maximum load levels in modern guns? A pressure gauge is the only way that I know. Not having a pressure gauge I must rely on the loading manuals and the use of a chronograph. If there is another way to determine or detect pressure tell me I'm listening.

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Back in 2002 I inherited a nice Marlin 30AS in .30-30 and first tried out a bunch of 150 & 170 gr. factory ammo on paper and over the chronograph, and kept records of it all. Then when I got my dies and started loading for it I just followed the loading manuals and chronographed all my loads. My intent was to stay within 30-30 ballistic territory and not push it too much. For woods type hunting 30-30 ballistics work just fine. When I want more velocity, flatter trajectory, etc. then I'll just use one of my bolt guns chambered for 25-06, 6.5x55, or 300WSM. But in the woods a 30-30 works just fine, except in some areas where, by law, I have to use a 12 ga. slug gun, which also works fine in the forest. One of my buddies volunteered to measure case heads for me but I never got around to having him do it as my velocities were never excessive, according to my chrono. Then I just went with the load that was the most accurate at 100 yds.

From all I have read over the years, sticky extraction will happen first in rear locking lever actions. As the receiver stretches and the bolt compresses (just a tiny bit) the cartridge expands to fit the larger space. When the gas pressure is gone, the bolt and receiver relax against an enlarged cartridge, putting lots of extra friction on the locking lugs. I believe the sticky extraction is really sticky unlocking, not the case stuck in the chamber.

Bruce

By the time you see indications of excessive pressures, the pressures will already be very excessive.

According to the many post on this forum in the past few months, there is no way to predict excessive pressures by case head expansion, blown primers or anything else. In a bolt gun, a blown primer would indicate high pressures, but how high, you wouldn't know without pressure testing equipment.

In a lever gun, a blown primer would indicate pressures way in excess of what the gun was designed for. A bolt gun will withstand higher pressures than other types, but blown primers is pushing the limits even with a bolt gun, and could very well go over the limits. A blown primer does not indicate that you have just reached the lower limit of primer blowing pressure, or if you have almost reached the top limit of the gun holding togather. Same for sticking cases and expanded case heads.

In a lever gun, you would use the same principles as for a bolt gun. That is, pick a starting load, cronograph it, and compare it to the velocity in the loading manual.

Be sure to use a loading manual where the loads were tested in a pressure gun.

So, you don't have a cronograph? Chronographs have just become readily avaiable to most handloaders, except the very wealthy, in the past 10 to 15 years, so what did you do then? For my loads, I just relied on the loading manuals, although I did pay attention to flattened primers and difficult extraction. If I experienced any of the so-called high pressure indications popular at the the time, I backed off.

And, on a few occasions, I did experience these indications. It is just my opinion, but I think flattened primers, hard extraction, and expanded case heads will tell you when you are getting higher than normal pressures--it just will not tell you how far over the limit you are.

By the same token, lever actions are a different matter. Normal pressures in a bolt action could very well be too much for a lever action, so the only thing you have to go by are the loading manuals.

One method I have used at times to duplicate factory pressures/performance: 1.Get a box or two of the factory loads you want to duplicate; 2. Measure case head diameter of new, unfired ammo; 3.Shoot a few and measure case head expansion; 4. Pull bullets from the rest of the brass and use with your choice of components for load development, starting low and working up until your case head expansion equals factory stuff. These days I don't bother with it much, I just look at several reputable data sources, compare their max loads, determine a good, rational starting point from that and shoot over the chrono until I get accuracy and speed I can live with.

bcp is right. I have pushed the limits of a Big Bore Winchester and one symptom of high pressure is lever kick. The lever will sting your hand a bit. The other is the sticky unlocking of the bolt. These symptoms will appear at well less than 50,000 PSI judging by the ballistics I obtained compared to pressure tested data. The Winchester 94 is a stretchy action that will quit working properly before you will be able to run pressures very high. I don't know about the other lever actions.

I use case length stretch to determine max loads in the Win 94. Full length sized cases will shorten a few thousandths when fired with low pressure loads since some of the neck is pulled back to fill the shoulder out. As you increase pressure the cases will measure the same after firing as before firing. I consider that as about max. Another grain of powder will stretch the brass a few thousandths beyond the unfired length but it still may be a functional and safe load. Another grain and you will probably have sticky unlocking. Primer appearance and case head expansion is meaningless. The case length is what you have to watch.

Ackley said that any modern centerfire rifle will hold
loads that pop primers. I doubt if it would be a "granade".
Good Luck

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I don't think that most lever guns will stand the pressure required to blow primers. The Win 94 AE is probably one of the weaker modern lever actions because of the angle eject slot cut into the receiver. That slot allows the receiver to stretch more than others. What does it take to blow a primer something over 80,000 PSI? I am sure that kind of pressure would cause a 94 to come apart or "grenade".

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I played with a couple wildcat rounds in the 94 a couple years ago and that is when I decided case stretch is the reliable pressure measure. I since have come across an article by Mic McPherson in Precision Shooting magazine about how he modifies the Marlin 1895 to feed longer cartridges. He states in the article that he uses case stretch to determine max loads in the Marlin. I believe the article is in the October 1998 issue.

I have a Conrograph and use for all my loads�
To me It is only useful if you know the max & min velocity of the load in question. The problem I have is with my 450 Marlin, I would like to use the 405gr Rem bullet but cannot find any load data for it� I can use �Load From A Disk� Software but there is no cross check so my comfort level is not very high� so In short I am very interested in learn the prevailing wisdom for gauging pressure in a Lever Gun

"With a bit of common sense, and by comparing data from various sources, one can now make fairly good guesses about 45-70 Marlin load safety. But when I began experimenting with this rifle, I could find no data to use, nor any to compare to. For this reason, and because I am an inveterate experimenter with a good background in both mechanics and metallurgy, I set out to determine actual safe maximum loads in my rifle. Today, the handloader has appropriate data from several sources. All the major reloading manuals list loads using various powders and bullets. Those sources should be referred to for loading data.

For several reasons, I would like to detail my experiments. First, they confirm the prudence of published data: Test loads generating significantly higher pressure than published maximums caused measurable case stretching. Second, this technique is the only one I know which establishes safety of any load in a rear locking action. Third, this process helped me develop several particularly accurate and powerful loads. Finally, it was fun, and I hope you will find it interesting.

While it might be possible to burst or swell a barrel with an extreme overload, a more practical consderation limits one to loads far below the pressure which would result in such damage. As noted earlier, this rifle uses what is termed a rear-lockup -- its locking bolt is several inches behind the cartridge head. Springing the action will allow case stretching as some critical pressure level. At higher pressures or with continued reloading of cases at this pressure, case separations can occur. Separations can be unpleasant experiences. A case separation occuring while considerable pressure remains in the barrel could be exceeding dangerous , even fatal.

Loads below the pressure level which will cause case stretching will result in some flexing of the action and a small amount of case springing. At these lower pressures, cases wil return to normal, unharmed. This is typical, even for cartridges fired in strong front-locking bolt actions. A certain amount of case springing, usually non-harmful, always occurs.

To check for the onset of stretching, I performed a simple test. After ensuring both the rifle chamber and cartridge cases were absolutely free from any form of lubricant, I fired a series of test loads. With each tested powder and bullet, powder charge was increased until case stretching occurred, as noted by any measureable increase in case length after firing.

Clean, dry cases and a clean, dry chamber ensured that the case walls would cling to the rifle chamber. This prevented the entire case from following as the head moved to the rear. Such an eventuality (caused by lubricated cases or chamber) would prevent stretching and invalidate this test.

To ensure my own safety, the gun was tied to an old tire and a long string was used to pull the trigger. Remember: Safety is the critical point in handloading. Do it safely or don't do it all!

When measurable stretching was noted, in even one of the three cartridges fired with each charge, I reduced the powder charge by at least seven percent to arrive at what I considered an absolute maximum load. This reduction was intended to allow for variations in primers, bullets, cases, powder lots, temperature, loading techniques, etc.

As noted earlier, every tested load extracted effortlessly, even those which caused significant case stretching. Therefore, do not assume sticky extraction will warn you of the existence of too high and dangerous pressure!

Loads I settled on as maximum caused no case stretching in my rifle and are evidently very easy on the brass. With the sizing die turned out two full turns, I have reloaded one batch five times. Chambering remains effortless. To date, I have experienced no case failures of any kind. However, variations in rifles and components can alter results significantly. For this and other reasons, I make no specific recommendations whatsoever. Loads listed in this article are only given for comparison. For loading data, I suggest the Speer No. 11 or Hornady No. 3 or No. 4 manuals."

M1895 Marlin Gives 45-70 New Lease On Life, pages 40-42, M.L. McPherson, Handloader's Digest/1994 Number 13, Edited by Bob Sell, DBI Books, Inc., 1994.

It is interesting to note that McPherson's 45-70 load for the 405 grain Remington JSP with H322 using this technique is only .5 grains more than the H322 load for the 400 grain Speer Hodgdon developed with pressure testing equipment and .5 grains below the Speer No. 11 H322 45-70 load for the 400 grain Speer.

That's with the nearly straight 45-70. Stretching a bit doesn't make it tight. A cartridge with a shoulder, when stretched between head and shoulder, will have sticky extraction due to the pressure that remains on the locking system after firing.

Bruce

The best safety practice with a lever rifle is the chronograph..You know where the velocity should be, so keep it there..I have seen overloads kick a lever action bolt open and eject a case and/or leave the case stuck in the chamber. Sticky cases are for sure a good indication of high pressure..flat primers with indicaters of the extractor on the case head..

Common since and good reloading practices are your best bet, trying to extract that last bit of OK out of a lever gun is not wise, you may get away with it in a bolt gun, but not in any lever gun that I know of...Lever kick is almost always your first indicator of pressure in a 94 or a Savage 99, even the smallest amount of lever movement is time to cut back a grain.

The best safety practice with a lever rifle is the chronograph..You know where the velocity should be, so keep it there..I have seen overloads kick a lever action bolt open and eject a case and/or leave the case stuck in the chamber. Sticky cases are for sure a good indication of high pressure..flat primers with indicaters of the extractor on the case head..

Common since and good reloading practices are your best bet, trying to extract that last bit of OK out of a lever gun is not wise, you may get away with it in a bolt gun, but not in any lever gun that I know of...Lever kick is almost always your first indicator of pressure in a 94 or a Savage 99, even the smallest amount of lever movement is time to cut back a grain.

I never go beyond book max with lever guns, no need to in the first place. I also try to stay at factory velocity..Straight walled cases can be particularly tricky so use the recommended loads with them..Too many folks want to make a 458 out of a 45-70 and then brag of brave deeds done and thats downright ignorant. It is what it is.

Several years ago a friend got himself a new Winchester 1895 in 405 Win. He fired some factory duplicaiton loads and reloaded the cases maybe twice. On the 3rd go round the rifle blew up destroying the receiver and his right wrist. The cases had not been measured or trimmed. On post mortem he noted that the loads did not chamber easily and required some effort to close the bolt.
It was determined that the cases had stretched and in combination with the very tight chambers of that particular rifle the bullets were probably engaged in the rifling resulting in an unacceptable overpressure.
A small inattention to detail by an experienced reloader.
The repair on his wrist was in excess of $25,000. Left him with a stiff wrist. Not a good thing for a surgeon.

Every Marlin I've loaded for has shown primer cratering even with mild loads or factory ammo. I think it's the stretchy action but I don't know.

Atkinson is spot-on IMHO- levers of this type are NOT made to be loaded hot.

You can load a Browning BLR to bolt-gun pressures since it's essentially a bolt action rifle with a lever. Also, pressure signs will be much more in line with what you see from bolt guns, much easier to read.

Just my .02. Trying to load a decent "stiff" load for my 45/70 was an exercise in discomfort on several levels- one of which was just that reading the pressure stuff was darn near impossible. For me.

atkinson... I agree... but in the case of the 405Gr Rem bullet for the 450 Marlin I cannot find any published data... just for a 400 Gr... So there is no benchmark velocity data --- in your experience should I just leave it alone?

Thanks

T

As ANYBODY knows who is a SERIOUS reloader of 45-70s, there are several levels of PSI recommended for various models AND types of 45-70s. On this, I totally disagree with Atkinson! He knows this already... so why insist on measuring psi based on what the factories produce for the 45-70 which is notoriously UNDERLOADED!

If you want to know, temmi, what your 450 Marlin is capable of go to the Buffalo Bore Ammunition site. That goes for the 45-70 as well.

There are more than one or two manuals... and they differ significantly. Some FACTORY loads are limited to around 18,000 to 23,000 cup. But NOT Buffalo Bore! Some MANUALS are limited to 28,000 cup (psi). Others to 35,000 cup, some to 40,000 cup (psi) and others to 50,000 cup (for the Ruger No.1) and others to 55,000 psi for the Ruger No.1. Most all of this is arbitrary on the part of the various companies because of litigation fears.

To temmi:
A 1.25% difference in bullet weight would suggest that using 400 grain bullet data for a 405 grain bullet is prudent. There can almost be that much difference within bullets of the same lot with some commercial bullets. There is no reason one cannot adapt 400 grain bullet loads for use with 405 grain bullets in your 450 Marlin XLR. Look how Mic McPherson came out with the 405 grain Remington and the 45-70 compared to Hodgdon and Speer published data for the 400 grain Speer and the 45-70. Just doing back of the envelope computations based on published 450 Marlin 400 grain Speer data, I derive maximum loads of 54.3 grains for Benchmark, 51.8 grains of H322, 44.9 grains of H4198, 59.3 grains of AA2460, 51.8 grains of AA2015, 58.3 grains of AA2520, and 46.4 grains of Reloder 7 for use with the 405 grain Remington JSP in the 450 Marlin. You would be on sound footing with considering maximum velocities for a 24" barrel of 1985 fps for Benchmark, 1998 fps for H322, 1934 fps for H4198, 2049 fps for AA2460, 2021 fps for AA2015, 2013 fps for AA2520, and 1938 fps for Reloder 7. So, do not exceed either the charges or velocities above. P.O. I'm not, but these are reasonable loads.

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Some of you have climbed on you "orange create" about not using hot loads. That OK but that is/was not the intent of this thread. The question is how does one recognize high pressure in a lever gun? We should be aware of pressure signs, not to push the limit to the last fps velocity or last psi of pressure but to avoid those areas. We all like to know the maximum SAFE load level for our guns even though we may not load to that level, we still want to know the comfort zone. Some of you are echoing the conventional wisdom which says: "start low and work up" or work up a load for your rifle. OK, that sound good in theory, but in reality it is worthless. Work up to what? Work up to case expansion or blown primers? If we are not to go there then what are the early warning signs? Do we add powder until we blow up the gun and our anatomy and say, Yep, that's a sign of high pressure better back off a grain or two?

Measuring case stretch is the only reasonable suggestion that we have heard. Are there other signs or do we just blindly follow the reloading manuals? All the things I've learned from years of bolt gun do not seem to apply to the lever guns, to which I am relatively new.

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