Finding a good load for Win 748 in .223
I happened upon a few pounds of Winchester 748 last year when my other favorite powders were in little supply. I decided to try to use up the 748 I had as opposed to the TAC that I normally use for training ammo. TAC's a little harder to get in quantity and I'm only able to find maybe a pound every two weeks or so.
I settled on a charge weight of 25.8 gr using a Hornady 55 gr FMJBT with a S&B SRM. Brass is usually Remington or PMC. I've been unable to chronograph this particular load but shot out of a 14.5" middy with an H2 buffer I was getting 2" groups at 100 yds and good reliability, but that was unsuppressed. Yesterday I took 250 rds of this load to the range to run some drills and do a little plate work between 50-100 yds standing. After all was said and done while shooting suppressed (Silencerco Saker) I had 7 feed ramp obstructions where the bolt slammed the round into the feed ramps, crushing the case and stopping the rifle. Clearance was accomplished by locking the bolt to the rear and removing the magazine. After a few of these stoppages I exchanged the H2 buffer for an H3 thinking the pressure curve of the Win 748 was doing something funky, but to no avail. The malfunctions continued intermittently until I was out of ammo.
With all that said, using the same bullet, brass, and primer but using 24.5 gr TAC, the rifle runs flawlessly using an H2 buffer, suppressed and unsuppressed. I still have over 4 lbs of 748 that I can load. Should I be looking at a higher or lower charge weight to shoot suppressed with?
In heavenly love abiding, no change my heart shall fear;
and safe is such confiding, for nothing changes here:
the storm may roar without me, my heart may low be laid;
but God is round about me, and can I be dismayed?
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