I recently built myself a .450 Bushmaster AR, 18" Bear Creek upper. I've been reloading and casting for about 11 years now and recently got into powder coating cast bullets. I found a post on another forum that I of course can't find now of someone using 27.0 grains of Lil"Gun behind a 405gr bullet I believe velocity was around 1550fps from a 16" barrel. So I gave this load a try, Lee 405gr Hollow Base that I use for my .45-70 Sharps, air cooled and sized to .452" with a lee push through sizing die, then powder coated in Eastwood Ford Light Blue 20 minutes at 400 degrees. Then sized again in the same die. Loaded with a fairly heavy crimp just past the last lube groove.
I shot ten rounds as a test today with no signs of over pressure, the gun cycled flawlessly, accuracy was a good as I can do offhand at 25 yards, recoil did not seem as heavy as Hornady Black factory ammo. I was too lazy to drag out my chronograph.
Now here is my question. For Powders I have a fair amount of Lil'Gun, H110, and a ton of IMR4198 because I shoot a lot of cast .45-70 and IMR4198 is my go to powder for .45-70. My question is does anyone here have any suitable 405gr loads with H110 or IMR4198 that will reliably cycle an AR? Thanks in advance for any advice.