44 MAg and WC820 problems

[MT Gianni]

At the NCBS I had a cartridge fail to fire locking up my pistol. It was 429421 over 19.7 gr of WC820 and a Win LP primer. The cartridge popped, the primer fired and the powder did not fire. The bullet stuck in the forcing cone tying up the cylinder. I drove it back into the case. The powder seems OK to look at, I will try to get some pics up tomorrow. None of the other 100+ cartridges loaded at the same time failed to fire, all had the same crimp. I am going to a Magnum primer with this load, working up again of course. Temps were in the low 80's and I use this below freezing. Any thoughts?

[9.3X62AL]

Same ones you came up with, use a magnum primer. Of course, why did 99% of the rounds run just fine, while that one putted? I didn't ask at NCBS, but was there a discernable variation between shots when the rounds that fired went off?

I lean toward a belief that the primer compound pellet may have fractured and some percentage of that pellet wasn't present at time of ignition. This assumes the anvil was present and in place, too.

[MT Gianni]

No variation detected Al.

[Dale53]

WC820 came in several different lots with considerably different burning rates. I "calibrated" my lot with H110 (as a standard). It was within .5 gr of the burning rate of H110. Your load would have been a "too light" load with my lot and I would expect to have problems at that level.

I regularly run 23.0 grs of WC820 behind a Keith 429421 for practice and 24.0 grs for hunting. I have fired THOUSANDS of this load without a single problem. HOWEVER, AS I MENTIONED ABOVE, THE LOTS VARY A GOOD BIT IN BURNING RATE. FAILURE TO HEED THIS COULD CAUSE SERIOUS OVER PRESSURE PROBLEMS.

The easiest way to determine your burning rate is to, first, get access to a chronograph. Then determine what a safe charge of H110 or Win 296 gives in velocity. Then, work up to that velocity (keeping in mind that some lots of WC820 are as fast as AA #9). When you reach the same velocity, then you have a "calibrated" load. So many grains of WC820 equal so many grains of H110 (or 296). KEEP IN MIND, THIS ONLY APPLIES TO THIS SPECIFIC LOAD IN THIS SPECIFIC CALIBER - YOU WILL HAVE TO DO THIS WITH EACH DIFFERENT APPLICATION - DO NOT "ASSUME".

I have had specific lots of brass that were too thin to give proper case neck tension with the bullets I was using. After full length sizing, the expander stem should be at least .003"-.004" less in diameter of the bullet to give proper case neck tension. No amount of crimp will replace suitable case neck tension with these slow burning ball powders.

All of the above is only a suggestion and your experience may differ. It is what has worked for me.

Dale53

[felix]

Dale, that will work for EVERYBODY. There are no exceptions to what you stated when the powders being compared are in the same burn range. Maximum pressures, instead of velocity, should be correlated when the powder speed/ignition range between the powders is thought excessive. ... felix

[MT Gianni]

I ahve been off line and running crazy. Lot is BAJ 47320. Charge was 21.3 vs what I had listed. I can not find the case to autopsy but am still looking.

[BD]

Dale is right on target. I've put a couple of those work ups on Castpics, and may put another up for the .450B with WC680, if it works at all. Also, My lot of WC820 is 47321. It tracked H110 up through 250 grain boolits, but strayed at boolit weights above that more towards AA#9. The "curve" can be different. My load is 21.5 grains of WC820 under a 265 grain WFN. Good for anything that breaths air. But for the 310 grain Lee RNFP I'm down at 18 grains.

To really "calibrate" a surplus powder requires: a chronograph, time, a pound of the closest canister grade grade powder, and at least two, preferably 3 firearms chambered in the cartridge of interest. If you go this route with only one firearm, keep it to yourself as that's all you have: "Your Gun".
BD