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dj, the thing is, the 6mmbr guys are likely using heavy brass, and match chambers. I'm running a loosey-goosey chamber, with moly, and light brass. The calcs cant be transferred over and make the same pressures.
It goes back to the fact that every rifle, and it's load components, are subtly different, but enough to easily cause a 10K difference in pressure.
I believe the folks publishing manuals understand this very well. That's why most of the book loads only calc to around 40K pressure range when I apply them into QL with my rifle/brass personal inputs.
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Campfire Kahuna
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What I'm curious is if you have tweaked the parameters to where the pressure tested load from 6.5br matches it's 54,400psi at 47.0grs with a 185gr bullet at 2701fps and then moved the powder charge up to the 50+grs to see what it says the pressure would have been.
And then with the parameters matched see what pressure 47-50+grs would make with a bullet 15grains heavier.
It doesn't mention the barrel length but if 46.0grs of Varget and a 155gr bullet is 3036fps it isn't a short one......................................DJ DJ; I figure likely a 27-28" barrel. Figure that the PMC brass is just about 56.0 grains of water capacity, and seat the bullet to 2.940" COAL. Moly the bullet. 47.0 grains of RL-17 then gives you about 99.5% capacity (matching what they were saying in the article), and estimated velocities of about 2705 fps.
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That's why most of the book loads only calc to around 40K pressure range when I apply them into QL with my rifle/brass personal inputs. Or again it might just be that QuickLoad is wildly off in it's pressure calculations! I've seen it be further off than this in other rounds (run some RL-15 loads in a 458 Lott and see what it says, maybe they've fixed it by now, maybe not).........................DJ
Remember this is all supposed to be for fun.......................
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Campfire Kahuna
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Campfire Kahuna
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My "go to" load with the 168 TTSXs (.2" groups at 100) is thus:
R-P brass, WLRs, RL-15 (54.0 grains), moly'd 168 TTSX, 3.495" COAL, and a 92.7% capacity load density.
QL gives the PSI numbers on that load at just a RCH over 58k PSI. The velocity estimate through QL is very, very close.
Now, run the same load through the "standard" Federal brass, no moly, at the spec'd 3.340" COAL, and you have a 102.0% capacity load, and you get 73,200 PSI.
So, WTF does this mean? You don't mention the other possibility of what your test might mean, and that is that Quickload isn't very accurate in calculating pressure between different brands of brass! I've shot a couple of the same loads in Lapua, WW, RP and Federal brass and shot them in several different rifles. Velocities have been pretty close between the different makes of brass. I Certainly haven't seen any of the changes that you'd think you would see in the difference between 58K and over 70K pressure. The velocity should be a good bit higher with the same powder and bullets between 58K and 70K pressures. I've seen Quickload estimate pressures at over 100K psi in loads that were spot on for burning rates and chronographed velocities. I've also seen primers popped in loads it said should be mild. I think it's a FAR less accurate tool than a Chronograph!.................................DJ If you don't change calculations for the change in brass capacity, you're fuggin' up, huge. No way in hell I'd even think about running a top end R-P brass or W-W brass load in Lapua or Federal. Likewise, a top end load in that brass is basically a starting load in the R-P or W-W stuff, due simply to the capacity on deck.
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Campfire Ranger
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I've seen Quickload estimate pressures at over 100K psi in loads that were spot on for burning rates and chronographed velocities. I've also seen primers popped in loads it said should be mild. I think it's a FAR less accurate tool than a Chronograph!.................................DJ I've always used QL in conjunction with the chrono, and indicators from the rifle and brass. Never relied on it as a stand-alone source of analysis.
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Campfire Kahuna
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Campfire Kahuna
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That's why most of the book loads only calc to around 40K pressure range when I apply them into QL with my rifle/brass personal inputs. Or again it might just be that QuickLoad is wildly off in it's pressure calculations! I've seen it be further off than this in other rounds (run some RL-15 loads in a 458 Lott and see what it says, maybe they've fixed it by now, maybe not).........................DJ Given that their calculations are pretty damned close given velocity, capacity, burn rate, burn percentage, and several other factors, I highly doubt that. I'd suspect that, and do suspect that, the difference in the variables (as Shane's pointing out) make more of a difference that you want to allow for, and that the manuals err on the side of less capacious brass and tighter margins due entirely to liability rationale.
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Campfire Kahuna
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Campfire Kahuna
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DJ;
Explain, then, how I'm supposed to find a top-end load for a rifle that has a COAL of 3.495" vs. the book COAL of 3.340", brass that has 4.5% more capacity, moly'd vs. naked bullets, and rather generous chamber/throat geometry. Obviously, the tighter specs on the book maximum aren't going to be maximum in that rifle.
So, how do I find "max"?
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My "go to" load with the 168 TTSXs (.2" groups at 100) is thus:
R-P brass, WLRs, RL-15 (54.0 grains), moly'd 168 TTSX, 3.495" COAL, and a 92.7% capacity load density.
QL gives the PSI numbers on that load at just a RCH over 58k PSI. The velocity estimate through QL is very, very close.
Now, run the same load through the "standard" Federal brass, no moly, at the spec'd 3.340" COAL, and you have a 102.0% capacity load, and you get 73,200 PSI.
So, WTF does this mean? You don't mention the other possibility of what your test might mean, and that is that Quickload isn't very accurate in calculating pressure between different brands of brass! I've shot a couple of the same loads in Lapua, WW, RP and Federal brass and shot them in several different rifles. Velocities have been pretty close between the different makes of brass. I Certainly haven't seen any of the changes that you'd think you would see in the difference between 58K and over 70K pressure. The velocity should be a good bit higher with the same powder and bullets between 58K and 70K pressures. I've seen Quickload estimate pressures at over 100K psi in loads that were spot on for burning rates and chronographed velocities. I've also seen primers popped in loads it said should be mild. I think it's a FAR less accurate tool than a Chronograph!.................................DJ If you don't change calculations for the change in brass capacity, you're fuggin' up, huge. Maybe according to Quickload, Not so much in the real world. I don't think that the calculations are accurate. I think you could load 168gr Moly'd SMK's and 46grs of Varget in any of the listed brass and not get velocity variations of more than 50-75fps, and certainly you wouldn't get over 70k Pressure unless you crammed the bullet way down into Mil-Surp brass. I know I've shot that load in WW, Lapua and RP with ZERO problems, I may have to reshoot the to get the actual velocity variations at the same temps on the same day though.No way in hell I'd even think about running a top end R-P brass or W-W brass load in Lapua or Federal. Likewise, a top end load in that brass is basically a starting load in the R-P or W-W stuff, due simply to the capacity on deck. Again, this is only a problem if QuickLoad is always accurate. It isn't................................DJ
Remember this is all supposed to be for fun.......................
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Campfire Ranger
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That's why most of the book loads only calc to around 40K pressure range when I apply them into QL with my rifle/brass personal inputs. Or again it might just be that QuickLoad is wildly off in it's pressure calculations! I've seen it be further off than this in other rounds (run some RL-15 loads in a 458 Lott and see what it says, maybe they've fixed it by now, maybe not).........................DJ In my years of experience with it, It's not wildly off in calcs with medium powders, in medium cases, and using medium bullets (that's about all I load). In my experiences It's typically within 25 fps on velocity calcs with the 308, and 30-06, when inputs are adjusted per the rifle/components. When you get on the extremes of cases, bullets, powders, probably more room for error.
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Campfire Kahuna
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Campfire Kahuna
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My "go to" load with the 168 TTSXs (.2" groups at 100) is thus:
R-P brass, WLRs, RL-15 (54.0 grains), moly'd 168 TTSX, 3.495" COAL, and a 92.7% capacity load density.
QL gives the PSI numbers on that load at just a RCH over 58k PSI. The velocity estimate through QL is very, very close.
Now, run the same load through the "standard" Federal brass, no moly, at the spec'd 3.340" COAL, and you have a 102.0% capacity load, and you get 73,200 PSI.
So, WTF does this mean? You don't mention the other possibility of what your test might mean, and that is that Quickload isn't very accurate in calculating pressure between different brands of brass! I've shot a couple of the same loads in Lapua, WW, RP and Federal brass and shot them in several different rifles. Velocities have been pretty close between the different makes of brass. I Certainly haven't seen any of the changes that you'd think you would see in the difference between 58K and over 70K pressure. The velocity should be a good bit higher with the same powder and bullets between 58K and 70K pressures. I've seen Quickload estimate pressures at over 100K psi in loads that were spot on for burning rates and chronographed velocities. I've also seen primers popped in loads it said should be mild. I think it's a FAR less accurate tool than a Chronograph!.................................DJ If you don't change calculations for the change in brass capacity, you're fuggin' up, huge. Maybe according to Quickload, Not so much in the real world. I don't think that the calculations are accurate. I think you could load 168gr Moly'd SMK's and 46grs of Varget in any of the listed brass and not get velocity variations of more than 50-75fps, and certainly you wouldn't get over 70k Pressure unless you crammed the bullet way down into Mil-Surp brass. I know I've shot that load in WW, Lapua and RP with ZERO problems, I may have to reshoot the to get the actual velocity variations at the same temps on the same day though.No way in hell I'd even think about running a top end R-P brass or W-W brass load in Lapua or Federal. Likewise, a top end load in that brass is basically a starting load in the R-P or W-W stuff, due simply to the capacity on deck. Again, this is only a problem if QuickLoad is always accurate. It isn't................................DJ So, what is accurate? A book with different brass, load COAL, friction proofing, and chamber geometry? I think not.
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DJ;
Explain, then, how I'm supposed to find a top-end load for a rifle that has a COAL of 3.495" vs. the book COAL of 3.340", brass that has 4.5% more capacity, moly'd vs. naked bullets, and rather generous chamber/throat geometry. Obviously, the tighter specs on the book maximum aren't going to be maximum in that rifle.
So, how do I find "max"? I discussed this on a thread here a few months back with Ken Oehler. Basically what I do when developing a max load is I make a chart for that caliber in a specific bullet weight and several powders. I make a chart of the max load listed from all available manuals and sources and look for a solid trend in the max load listed, discounting any low or high values. I also record the velocities with the listed max loads. I'll load up 4 or 5 powders and see which one seems to give good accuracy and velocity, I'll stop whenever I either reach the max powder charge or the max listed velocity. You won't always be able to reach the max listed velocity but usually I've been able to get close. For me the max listed velocities, max listed loads or pressure signs all three were limits I don't usually cross because if you exceed any of them you probably are also exceeded max pressures. Ken Oehler pretty much agreed with this. IIRC the thread was one about using the chronograph to determine pressure or something like that if you want to search it up....................................DJ
Remember this is all supposed to be for fun.......................
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Campfire Kahuna
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Campfire Kahuna
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So, what you're saying is that you guess.
If your brass is more capacious than the listed brass, then you have less fill density, and less pressure.
If you have a longer COAL, then you have more capacity and less fill density, and less pressure.
If you run moly, then you have less friction, and less pressure.
Yet, you're convinced that if you have all three of those variables in your favor to reduce pressure, you need to stop at or near the maximum load for something that's no longer equivalent?
That's completely illogical.
You go through all those machinations, guessing against the facts, and then think that a program designed to compensate for all those variables is less accurate?
Damn.............................
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Campfire Ranger
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...I've seen Quickload estimate pressures at over 100K psi in loads that were spot on for burning rates and chronographed velocities. What were the details of this load?
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So, what you're saying is that you guess.
If your brass is more capacious than the listed brass, then you have less fill density, and less pressure.
If you have a longer COAL, then you have more capacity and less fill density, and less pressure.
If you run moly, then you have less friction, and less pressure.
Yet, you're convinced that if you have all three of those variables in your favor to reduce pressure, you need to stop at or near the maximum load for something that's no longer equivalent?
That's completely illogical.
You go through all those machinations, guessing against the facts, and then think that a program designed to compensate for all those variables is less accurate?
Damn............................. You might want to go back do a search and read some of JB's posts on how little long seating bullets and the small increase in capacity makes on velocity potential. Moly doesn't increase velocity potential without increasing pressure nearly as much as some people assume. I think you might be exaggerating the effects of small differences in case capacity and seating depth, but don't take my word for it read what JB has put in print about it, he's a better writer than I and has hung around some ballistic labs. Maybe he might comment on this for himself which would be better yet. The thing is that I'm not guessing about anything. I usually have data that has been actually pressure tested and shot not just calculated. I have velocities that I actually measure in my gun. If you don't exceed the books maximum listed loads and don't exceed their max listed velocities at their COAL with the same components you can be pretty sure you aren't exceeding max listed pressures (this per Ken Oehler on the earlier thread). Simply put I agree with Brad. If I want 200gr bullets going faster than the listed velocities of the 308 or 30-06 I'll buy a 300 Mag (well, I have several). I don't beleive that it's smart to push a caliber beyond it's limits. I also hope that RL-17 turns out to be a great powder for the 308, I have a bunch of them. I just don't think it's smart to go so far beyond published limits to squeeze the last Nth out of a round................................................DJ
Remember this is all supposed to be for fun.......................
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...I've seen Quickload estimate pressures at over 100K psi in loads that were spot on for burning rates and chronographed velocities. What were the details of this load? It's been a few years ago and I'm on my 3rd laptop since I had that Quickload installed. If memory serves it was with a 500gr bullet seater to the cannelure and RL-15. I need to try and find it and see if I can reinstall it on my new laptop and duplicate it. I quit using it because it was so far off on the 458 Lott and a couple other rounds I used it for didn't seem that accurate either (not as bad as it was on the Lott though). It used to have a reputation for not working well with straight walled cases - but again to be fair it was a few years ago and they may very well have fixed the problem by now...................................DJ
Remember this is all supposed to be for fun.......................
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Campfire Ranger
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Looks like a full case only calcs around 58-60K.
Cartridge : .458 Lott
Bullet : .458, 500, Hornady RN 4504
Cartridge O.A.L. L6: 3.600 inch or 91.44 mm
Barrel Length : 24.0 inch or 609.6 mm
Powder : Alliant Reloder-15
Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.19% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !
Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms
-11.9 92 74.00 2094 4867 44711 6198 98.2 1.473
-10.7 93 75.00 2120 4988 46451 6265 98.5 1.449
-09.5 94 76.00 2145 5109 48258 6330 98.8 1.425
-08.3 95 77.00 2171 5231 50136 6391 99.0 1.401
-07.1 97 78.00 2196 5354 52088 6449 99.2 1.378
-06.0 98 79.00 2221 5478 54117 6504 99.4 1.355
-04.8 99 80.00 2247 5604 56226 6556 99.6 1.333
-03.6 100 81.00 2272 5729 58421 6604 99.7 1.311
-02.4 102 82.00 2297 5856 60703 6648 99.8 1.290
-01.2 103 83.00 2322 5984 63079 6688 99.9 1.269
+00.0 104 84.00 2346 6113 65553 6725 100.0 1.249
+01.2 105 85.00 2371 6242 68129 6759 100.0 1.229
+02.4 107 86.00 2396 6372 70814 6788 100.0 1.210
+03.6 108 87.00 2420 6503 73612 6817 100.0 1.191
+04.8 109 88.00 2445 6634 76530 6844 100.0 1.172
+06.0 110 89.00 2469 6767 79575 6871 100.0 1.154
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It looks like they've probably fixed the problem. The load I've been shooting was 80.0grs, I'll have to find the chrono data on it but I think the velocity is still 100fps or so off. I remember that it said that 80.0grs was way up in the red range before, at least now it shows it well down in safe territory. The lower the pressure the better on the big African Calibers........................DJ
Remember this is all supposed to be for fun.......................
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Campfire Ranger
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I started out with V2.8 back in 2002. It was right on the money with RL15, 308 Win, and moly'd 190 SMK.
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I found my chrono data on the Lott and my velocities are about 110fps off the track you've printed. That much could be explained by my rifles. At least it's a lot closer than it was! I'll have to check and see which version it was that I ran.................DJ
Remember this is all supposed to be for fun.......................
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Campfire Outfitter
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Let's take a look at something, JFSAG..........
Sierra 168 BTHP MatchKing loads.
Sierra 5th Edition lists this as the maximum load with RL-15:
51.2 grains, and 2900ish fps
That figures a 3.285" COAL, 1-10" twist, 26" tube, Savage 110, Federal cases, and Federal primers. No moly.
Hmmm...........
Federal cases generally run about 68.0 grains of water capacity, so that's the spec I'll punch into QuickLoad.
QL calcs that load at 53,811 PSI. Having shot that load, it's mild, and the pressure spec'd is likely about right, as you can generally go a good bit above that before you see pressure signs.
Even so, let's see what changing a few parameters nets.
Use R-P brass (71.0 grains, average, water capacity), run moly, and seat to 3.385" COAL.
The exact same load runs only 44,990 PSI. That's a HUGE difference.
VA - this is exactly the kind of info and quasi-calibration I was refering to in my earlier posts. I tend to trust math models IF they are calibrated in some fashion and verified with other known end points. An uncalibrated math model is nice cartoon. I've routinely run 3-4 grains over book max in the 30-06, 280 , and 7RM to account for the lower SAAMI (usually 57-58K) but i always establsh boundaries using "normal" chamber/throat dimensions. For me 2800 with 180's in an 06 using a "normal" throating chambering geometry and COAL. I agree that more capricious brass, longer throat, significantly longer COAL - anything that makes the powder room bigger lowers pressure and resultant velocity. I have no issue with going over book max as long as there is some type of method involved other than my gun didn't blow up, or I have no sticky bolt lift, etc. Guessing ain't cool - too many folks decide on a desired velocity and try to justify their data because of the factors cited above. Apparently you guys are not - a very good thing BUT folks need to understand the differences in what MM is doing vs what they have/plan to do. I think the last 2 pages or so has helped me understand better. Thanks.
Adversity doesn't build character, it reveals it.
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