Miscellaneous testing

I wanted to compare my old 162 gr. Penn Bullets loaded with 5.5 grs. of A#5 to Steel Valley 158 gr using the same charge. I found the 2 bullet types were within 6 fps of each other but neither hit a velocity high enough to reach the old IDPA 125,000 power factor. Something that both bums me out and mystifies me. I have used this load for YEARS for club IDPA and never had a problem. Last year at about this time I posted test results here using this load as good! Now using powder from the very same 8 lb. keg, I've lost at least 25% of the previous velocity. Similarly using Steel Valley's 147 gr. RN and a 5.6 gr charge of Silhouette, I find a loss of right around 100 fps from an average of 841fps to 745 fps. Using powder from the same lot as the original testing though a 1 lb. canister opened a few months ago.

I'd bet $$$$ to donuts that the problem is NOT the BULLETS! Testing has changed, I'm using a Shooting Chrony Beta. Prior testing was done on a Pact 1 XP. I wish I could set them up in tandem and see if there's a difference! Is it possible that the powder deteriorates that quickly?

Also to answer a question I'd asked earlier about what trigger pull weight is sufficient to fire which primers. I can tell you that My Model 67-5 at 7.5 lbs with the Trigger Job performed by Mark Hartshorne lights off Federal, CCI or Winchester without skipping a beat. My Model 10 (retuned to its maximum 8.5 lbs. pull) won't fire either CCI or Winchester. So for .38 Special I'll have to stick with Federal (or perhaps replace the main spring in the Model 10).

All this from today! Probably because it'll be the last outdoor range trip until spring!

Did you do the latest test now that it is cold? You can lose a lot of velocity vs testing during the summer (but usually not 100 fps in a pistol).

Also is your seating depth the same as before? Seating a bullet deeper can increase pressure (and velocity). And by seating depth I mean the amount of the bullet actually in the case. OAL means nothing with different nose configurations. Its the length of lead pushing down in the case on the powder that is important.

Its not your powder going bad. Smokeless powder might lose lose some energy with age but that will take many decades (or centuries).

So if every thing is the same I will report you to the IDPA for cheating at your club matches.

Temp today was 40 - 45 degrees F so not that cold. I don't trim my .38 cases I just shoot them 'til they crack, but even with that and the relatively mild loads I'm shooting (even though I always try to hit PF, they're not +P), I haven't noticed a problem until recently. The bullets are all cannulured and I always seat to the foremost edge of the crimping groove, so seating depth stays uniform despite OAL or case length. BTW IDPA has reduced their PF for .38 Special, the last I heard it had been dropped to 105,000 because factory loads are so anemic, (but I'll give you a prop for effort). My club gave up on IDPA a few years ago because of the manpower requirements they dictated for club matches. There's only 5 of us regularly doing the work of set up, tear down and safety officers. So we do mix of IDPA, Practical Pistol and others to make an interesting mix.

I suppose I could send the chrony back to the factory for calibration testing. Or I could just increase my A#5 powder charge to 5.8 or 6.0 grs.