Hi everyone! This is my first post on this forum. I've been a long time viewer, and finally decided to make an account.
I recently built an AR in 350 legend with the express goal of using cast lead projectiles. My upper is a Bear Creek Arsenal with a 16" 1:16 twist barrel and carbine length gas system. I'm actually quite impressed with the quality of this upper, all machining and finishing is very clean when considering the price.
I first got a Lee 358-200-RF mold with generally poor results, the projectile is just too short for semi-auto function and reliable chambering in my rifle. I then got an NOE 357-189-RF mold that is functioning much better. I'm using WW alloy that I've enriched with ~0.5% copper (using copper sulfate). Bullets are powder coated, NOT gas checked, and weigh at 195 grains. They are sized to 0.357 and seated to 2.17". Cases are Starline and trimmed to 1.705".
Using 22.0 grains of H110, I'm getting reliable cycling and roughly 1.5" groups at 100 yards. My one and only issue is that I'm getting an occasional pressure sign on 1 out of every 5 casings. On these casings, I'm mostly seeing slight ejector shearing marks. Even less often, I'm seeing occasional mild primer flattening and extractor marks on my head stamps. I'm not certain if this is due to my rifle being overgassed, or if these are actual pressure signs. I've noticed an occasional thin ring of shaved lead left over in my throat, which may be creating excessive headspace on the subsequent round. Using Gordon's reloading tool, I should be running 40-45k psi.
This particular cartridge is a new concept to me, and I'm not entirely certain of how I should interpret these results. H110 is a new powder for me, and with almost no load data available, I'm curious if this may be a result of too low of a charge. I unfortunately don't have access to a chronograph right now.
If anyone may have some input or advice, I'd love to hear it!