450Bushmaster.net

My ignorance of platforms other than .223 is going to show now. On a .308 upper, like an AR10 or LR308, besides the obvious caliber difference, are the barrels a different form factor than a 223 based upper? I ask because I was wondering if one had say an LR308, could one simply place an MGI 450B barrel on it to change to 450B? The 308 bolt is already .473 rim diameter like the 284 parent cartridge. I imagine one would have to fabricate a magazine insert to restrict the travel of the cartridges as a result of recoil.
Thanks,
Hoot

The barrels, from what I have been told are a different dimension.

In an AR 10 rifle, you certainly could have one made to shoot a 450 bm.

THe question raised in my mind would be why? the AR 10 platform is not a standardized thing and it is a lot more expensive.

Certain uppers are made to work with certain lowers, I think Ive read that certain uppers have diferent barrel extension diameters and the like.

with the AR 15 within reason EVERYTHING fits EVERYTHING. thats one of the beauties of it. I have an R25 in 243 winchester still in the box. Curioscity hasnt gotten ahold of me enough to do a rundown on it, and as soon as I tear it down, its no longer factory condition.

That's a valid question and point. I already have a 223 platform that's tweaked and I don't want to cannibalize it. If I'm getting a new platform to build upon I figured get something new, like one in .308. If I fall out of love with the 450B, I still have a new caliber quasi-AR platform to play with. I already have 308 dies, brass and bullets to play with for my G3. That's the only reason for looking outside the box. Also, a 308 platform is ripe for 7mm-08, 338 Federal and 358 Winchester. Just trying to stay ahead of my hunger for new things to work on during the long winters up here.

Too bad the military never spec'd a 7.62x51 AR. I knew you could not swap Armalite and DPMS 308 parts.

Thanks for taking the time to chime in,
Hoot

everything is bigger on the 308 platform, barrel, extension, bolt, carrier, etc.

But by how much al? and for sake of discusion, could an ar 10 barrel extension be safely turned down to fit the AR 15?


I have a deep seated longing for a 50 cal using wssm brass, kinda like the 450's big brother. But wssm extensions and bolts are rare as hen's teeth.

Al in Mi wrote:everything is bigger on the 308 platform, barrel, extension, bolt, carrier, etc.

the magwell is also bigger

Al in Mi wrote:everything is bigger on the 308 platform, barrel, extension, bolt, carrier, etc.

So, the shank of a 308 AR barrel is bigger in diameter than the shank of a 223 AR barrel. Well, That kills that idea. Another cabin fever pipe dream dashed...
Thanks for the update guys. Anybody have an opinion on a complete RRA lower populated with their NM LPK versus complete CMMG lower populated with whatever LPK they use? These would be as opposed to the complete Bushmaster lower populated by whatever LPK Bushmaster uses. Trying to stay under $300 for the complete lower. I've discovered that trying to determine which stripped lower and LPK to use based upon opinions around the web is futile. Too many people with conflicting opinions. "A moose is a horse designed by committee"

FWIW, if I want to go as cheap as possible, the best I can easily do on a complete 20" A3 rifle build is $495. Add MGI bolt and barrel and I'm looking at $800.

Hoot

complete bushmaster a2 lower from impactguns.com is $299.....

dang, i thought this thread was gonna be about why isnt there a 450b style cartridge in the .308 pattern AR rifles.... talk about some power

thebrassnuckles wrote:dang, i thought this thread was gonna be about why isnt there a 450b style cartridge in the .308 pattern AR rifles.... talk about some power

AR10 chambered in 45/120