Quickload errors in elevated pressures

[Clark]

Quickload errors in elevated pressures in 7.62x25mm Tokarev

I did some overload experimenting with a Polish Tokarev today:
5) "AA loading guide #2" 2000, 8.5 gr AA#5, 86 gr FMJ, 1.316", 1717 fps, Starline brass, CCI500, 41.5 kcup, ok in CZ52

a) 10.5 gr AA#5, 86 gr .54" S&B pull FMJ, 1.316", Starline brass, wsp, ok in Polish Tokarev
b) 11.5 gr AA#5, 86 gr .54" S&B pull FMJ, 1.316", ex groove +.005", primer fell out, Quickload 93 kpsi
c) 11.5 gr Power Pistol, 86 gr .54" S&B pull FMJ, 1.316", ok in Polish Tokarev, beats AA#5 in recoil, Quickload 107 kspi

What Quickload admits is that the program cannot predict straight wall cases. Too much powder may go out of the barrel unburned and Quickload assumes worst case. But today I compared the limits of brass with a bottle necked cartridge.

The error Quickload makes is thinking 11.5 gr of Power Pistol is higher pressure than 11.5 gr of AA#5. The AA#5 load causes the extractor groove cut to expand .005" and the primer falls out. The Power Pistol 11.5 gr load does not cause any extractor groove expansion that I can measure with my dial calipers.

So here is a bottle necked cartridge that Quickload gets wrong.

What can Quickload get right?
When using rifle powders in rimless cased .223 or 8x57, Quickload usually predicts ~65 kpsi when the bolt gets sticky and the primer pocket gets loose.

 

[Clark]

Here is a picture of 11.5 gr AA#5, 86 gr

This Starline brass is about 1 gr weaker than S&B brass, but the Starline comes without those aggravating bullets I have to pull.

 

[saands]

I have found that Quickload does a much better job predicting the performance of some powders than others. This leads me to believe that some of the powder data may be from a different decade ... and that the older powders may have evolved a little over time.

I have been doing some testing with the straight walled pistol bullets like the 32acp and the 45acp and have been pretty impressed with QL's correlations to measured velocity. I'm assuming that if the velocities are in line, then it is likely that QL's pressures are also in line with reality as the calculations must be going from pressures to accelerations to velocities, right? It therefore seems unlikely that you could get the pressures all wrong and still do well predicting the velocities. Maybe my logic is flawed here, if so, please point it out!

I haven't had enough simulation time to actually note a correlation between the form factor of the case and the reality of the prediction, but I can say that I was amazed by the program's ability to point me in the direction of V-V N-350 for the 32acp ... everyone else (including VihtaVuori) said that it was too slow of a powder, but it works very well ... and very much like QL suggested that it would.

I'll be looking at some interesting 300win mag loads in the next couple of weeks and it will be interesting to see how it works with 110 grain Vmax and 65 grain saboted vmaxes ... especially since the latter is supposed to be in a totally new neighborhood for me ... the 4200+fps neighborhood

Are your "test" loads going into the realm of compressed charges? If there is one thing that I have learned in my time reloading, it is that this is a VERY non-linear game and extrapolation is a dubious venture, at best!

Saands

 

[Clark]

I have been doing compressed loads this week with the 9x23mm. Anyone who can get 20 gr of LONSHOT to fit under a 158 gr bullet with an OAL of 1.36" has the double comression process under control. I had to get a bigger press yesterday.

But today's data was not compressed. AA#5 has the highest quickness - density product I know. If AA#5 can't blow it up, no powder I know can.

I agree about QL on the 45acp. The loads I have shot that the primer falling out are in the 65kpsi range.

But 32acp I shoot and carry is evaluated by QL as being over 1,000,000 psi.
If that were real, I would have to go to a thicker primer

 

[saands]

Alright ... I'll bite ... what pistol do you shoot that 32acp in and which powder is it? No need to tell me the quantity, I'm not likely to go give it a try ... although I'm interested in seeing if you are using one of the Accurate Arms powders. Looking at the 32acp, I ran a correlation of published velocities (data from the powder manufacturers' manuals) versus the predicted velocities from QuickLoad and got an R squared of .94 ... which I thought was pretty good. The funny thing is that the QuickLoad predicted pressures for the Accurate powders (#2 and #5) were right around the same as the Alliant powders in similarly performing loads, but the published pressures for the AA powders were about double those of the Alliant powders. Now, I'm inclined to think that something is fishy with the AA published data ... for both AA#2 and AA#5 to spike THAT fast and give up the ghost fast enough to keep the same area under the curve they would have to be REALLY different ... and it just seems very unlikely ... I'm not generally a believer in simulated data, but I'm struggling to accept the published stuff in this case.

saands

 

[Clark]

I have shot 6 gr Power Pistol with 85 gr and a stock feed ramp, and I have carried 5 gr Power Pistol and 85 gr. I can only carry one Speer 85 gr, the one in the chamber. The problem is the extracting round rim digs into the soft point of the 85 gr bullets waiting at the top of the magzine.

I now carry 60 gr Gold Dots, which is a wimpier bullet, but I have a friend who says the expansion is near perfect in wet phone books.

I have loaded real hot 110 gr loads in the P32, but the recoil caused the hold open to break [I'm not sure how].

I am waiting for the arrival of my P-3AT. I have been shooting some 158 gr bullets in an M1903, and I like the .380 allot more than the 32acp as a starting point.