subsonic 450bm

[mike_kaleigh]

I have been thinking about a new project gun, I was wondering if anyone has experimented with subsonic heavy 450bm in an ar15. I am wondering if you can get subs to cycle reliably. I was going to pick up a lee 405 or heavier to start with. seems like all barrels are 1 in 16 twist, carbine gas. And is carbine gas OK or should I get a custom pistol gas barrel like is preferred with 300blk.

I was just wondering what you guys have figured out to save me a little time and headache or if it is a waste of time.

[mehavey]

From experience (https://www.thehighroad.org/index.php?threads/heavy-cast-450-bushmaster-subsonic.917356/), cycling will be an issue.

[BK7saum]

FYI, the 450 bushmaster utilizes 0.451/0.452 bullets, not .45 rifle bullets. Of course you could size 0.457/0.458 bullets to 0.452, but wanted to make sure that you knew the BM was developed around .45 pistol bullets.

[mehavey]

322790
[smilie=w:

[cwlongshot]

I have been shooting them IN MY BOLT for years. The 457124 sized down. Also a Lyman 450g with Unique. I was using green dot because I had so much, but Unique was better. Never wanted to try in the AR. A 450g @ 1050 fps really packs a wallup on targets!!

CW

[mike_kaleigh]

Well thanks guys for putting an end to my dreams of 450bm with cast boolits cycling in an ar15. But that is fine maybe I will wait for the ruger gen 2 in 450 to come out. and get a folding chassis for it. And I know 450bm was designed for pistol boolits but i was just looking at 458 for the heavier weight and size down.

[mehavey]

i was just looking at 458 for the heavier weight and size down.
520grains (https://castboolits.gunloads.com/showthread.php?464885-subsonic-450bm&p=5681135&viewfull=1#post5681135) enuf' ?

[lar45]

I have some .458" 405s sized down to. 452" that I've shot around 1100fps in my Ruger 450bushmaster AR.
I'll have to check my notes, but I think I used Unique and just cycled them by hand.

[Jbiker]

here's a question !! I'm loading barnes 275 gr tsx copper bullets for the ruger BUSHMASTER BOLT GUN.
So far in the prep work , starling cases ,all trimmed to 1.691. +/- .001, cci 400 sr primers and 4227 powder @35 grains . The coal @2.228 +/_ .005. I'VE BEEN GETTING A VELOCITY BETWEEN 1400 AND 1600 FPS and the best grouping at 100 yds for 1.8" X.8 ".
Has anyone got or found load data or results using this bullet with H335 OR H322 ? If one seats the bullet at the 2nd cannula (closest to the ogive) these bullets seem to be long at 2.330 COAL . also it appears that anything over 45 grains of H335 would be getting into a compressed load area. So before I go and try anything ,I figured I'd kick the question out there for comment's ..
No I'm not rookie, been reloading for the last 5 decades. But there doesn't seem to be a lot of data out there that I've found to date .! Comments ? please !