Popping primers in mex match

[bubba04]

After reading some threads here on rolling match ammo out of crap from mark I went off and did the same and had some weird results.

Several years ago I was able to procure some cheap 7.62x51 147 gr ammo for Pakistan for 25 cents a round delivered. This stuff is berdan primed. This was origneally bought as plinking ammo for a hk91, however I subsequently sold it, and am currently using the surplus bullets for 300 blackout and would like to use the brass for some precision loads when I dont want to pick up brass, or out hunting.

I started with my same load I have been loading in Lake city brass and winchester large rifle primers

175 gr nosler hpbt 41 gr benchmark COAL 2.805. I load on a dillon 550 using dillon powder drop and lee dies.

When shooting this load I have no signs of over pressure and it is not at the top of the powder tables. However when I shoot this exact same load through my POF berdan brass I get primers coming out at an unnerving rate (20-30%). However the primers that do stay in the brass dont look melted. Could this be an issue of berdan primers compared to boxer primers?

I am shooting these loads through my 16" LMT MWS.

Any ball help would be appreciated.

[markm]

Odd. I'd try a slower powder. Benchmark is VERY FAST for a 175gr bullet in .308. IMR 4064 is the answer for that load. Varget is nice too. Neither will meter as good, but they're more appropriate. Norma 202 will meter good and give you metering almost as nice as Benchmark.

I only run Benchmark for light (55 gr) .223 bullets.

Alternatively BL(C) 2 or WW748 would make good ball powder options.

[bubba04]

interesting I didnt think about that. I know benchmark is on the lower end velocities of the powders listed in the Lee reloading manual. I actually got started with Benchmark as it was the only rifle powder that I could get a bead on last December. Sorta sucks as this load is magic in my rifle (best group .78 MOA 5 shot group at 300 yards). Though I imagine it lacks the FPS to actually get pushed farther out.

Thanks for the powder recommendation, I will see if I can grab some and give it a shot.

You think its just the magic combo of the crappy brass/primer with powder that causes the primer popping, where as with LC brass and hornady brass it doesnt matter?




Odd. I'd try a slower powder. Benchmark is VERY FAST for a 175gr bullet in .308. IMR 4064 is the answer for that load. Varget is nice too. Neither will meter as good, but they're more appropriate. Norma 202 will meter good and give you metering almost as nice as Benchmark.

I only run Benchmark for light (55 gr) .223 bullets.

Alternatively BL(C) 2 or WW748 would make good ball powder options.

[markm]

There may be a factor with the berdan priming system as well. I'd guess that the lower velocity is because of the early pressure spike. In order to get Benchmark to achieve what an appropriate powder will get you, the pressure would spike too early. That's why you see lower velocities.

[bubba04]

Sorry I am strictly going off velocities quoted from Lee manual. I have not used a chrono on the load. But I bet your right, the combo of the Fast burning powder and berdan primer are causing the spike.

I have been pondering this problem for nearly a month, thanks for the help & guidance.