I know I'm late to the party but it was fun.

Roman couldn’t wait to test the .450 Bushmaster. I used Hodgdon’s data and the Hornady 250 gr. pointy tip bullets, LilGun powder and Remington 7-1/2 BR small rifle primers. The data listed a range of 35 – 38.5 grs. charge and a velocity range of 2158 -2289 fps from the 24” test barrel. The pressures are notably lower with LilGun as, is typical, peaking at 35,900 psi. That’s about all the capacity you can get under the bullet. I noticed the powder reacted much like a pistol with the straight case, reaching a plateau and leveling off. The progressive steps are more pronounced with a “necked” cartridge. Also the velocity loss per inch of barrel reduction is usually much greater.

I loaded a starting range of 35, 37, and 38 gr. series of test loads. We also found that about any magazine we used from a modified AR/20, dedicated 350 Legend, and Milt. AR 30 rnd., they all seemed to work acceptably. Brass was ejected a short distance and was in a neat pile, not scattered. All case mouths remained rounded and were not pinched; cases were not scratched or beat up. Checking primer appearance and cases after each series did not show any notable differences. Indention was rounded edges and not flattened. Roman claimed he “felt” the progressive recoil was increasing but the velocity did not support that. Perhaps he was just being tenderized. Lol Recoil is a factor to consider, if you think a .270 recoils, perhaps this is not for you.

We did a short amount of shooting, limited by my available supply of brass. The results were a span of only 2048 – 2107 fps over the 3 grain charge progression. Listed pressure is a 3,000 psi range from starting load to max. H110 and 4227 are a couple other powder options and show 1,000 psi higher levels with lower velocities. It makes sense to try to stick to starting loads and move up to find the most accurate loading. Power is all the same so why waste powder.

It’s a bit like I have the answer but forgot the question. The .450 BM pistol is a fun project allowing .454 Casull or .444 Marlin power in a 7 lb. compact “pistol” platform. It is not expensive to set up, only costly if you do not reload. It’s just a toy to me for exploring the cartridge. It would certainly make an effective and handy rig for hunting hogs or such! The straight wall case behaves a little differently but I also only lost 100-200 fps over a barrel range dropping 13.5”. That is an interesting and big positive. If we decide to keep this little beast Roman declared we invest in an actual "Chambered brake" to help the recoil a little. I concur.