Originally Posted by
GooseGestapo
fwiw;
Ive been tinkering with a .300blk I made up from used parts I aquired along the way.
Most significantly, barrel is an R-Guns, 1/8" 16" WITH MID LENGTH GAS PORT. This has had to be drilled out to .120" to get adequate gassing to function with 125grn supersonic -Lock open after last shot from magazine.
I mostly wanted to be able to shoot cast as I was largely put out of commission by the panic of '08 and '11. But I did have cast boolits!
IT's been a challenge to get the gun to work with cast. My last batch of 155 grn PtdGC's were a bit soft, ( some left over 50/50 ww/pb lubed with home made lube (Bens red, TERRIBLE,!!).
I stripped the lube, re lubed with SPG, then tumbled lubed. Better, but...
i've gotten best accuracy with ww/+2% leadfree solder added;
lastly, using Acc1680 @ ~19.0grn for ~1,950fps. However, I'm OUT. Can't find any except 1lb online. So, I worked up a load that will function, but not blow primers like H110 @ 16.5grn. (Works, but is TOO HOT!). Hod. Lil'Gun, H4227, H4198, BlueDot, #2400, no luck. Not enough gas volumn.
I found that Acc5744 works at 17.5grn, but is running 2,050fps and is too much for my soft alloy. Same bullets shot 2" from a 1943 SMLE over 30.0grn of H4895 this afternoon @ 1,700fps, slower twist. .300blk shot like a foot groups at 100yds. I did get a ~5" group at 50yds as I was blowin them out, to get rid of them (I only have a bit over 100 cases made, so didn't want them "occupying valuable space..."
I hope you've found some useful information in my ramble...