450Bushmaster.net

I'm thinking of building a 450 upper with an 11-12 inch barrel for suppressor use.
Any thoughts on this, barrel length, velocity with the shorter barrels, etc.
I already have a 20" upper and with a suppressor it is extremely long and heavy.
Thanks

Can't help you with our specific question but felt like sharing an enigma that I happened upon last night as an FYI.

In the "think tank", which I keep stocked with old copies of different firearms rags, that I eventually read from cover to cover, save the political BS. I was reading a review of the CMMG Guard, 45 ACP AR style rifle with 16" barrel. The muzzle velocities reported with different commercial ammo listed the 230 FMJ ball as clocking out at 950fps. That struck me as odd since a Govt M1911 with 5" barrel, shooting 230 FMJ ball specs out at 830fps. Hard to believe that 11 more inches of barrel only accounted for 120fps. I'm sure there's an explanation...

I'll take this mystery of life and step aside while others with experience relative to your question, wade in.

Hoot

had this saved from a article I read awhile back on Windham's 9" pistol. https://www.americanrifleman.org/articl ... 15-pistol/




as far as your 45acp reading Hoot, that might be all you can get from 6-8gr of powder

First time seeing that chart. Another member here posted recently about the 9" Windham and was told by Windham it would make 2000fps with Hornady ammo. I thought that was optimistic, figured maybe something between 1800-1900fps, apparently not even that much.

T3BEAR wrote:I'm thinking of building a 450 upper with an 11-12 inch barrel for suppressor use.
Any thoughts on this, barrel length, velocity with the shorter barrels, etc.
I already have a 20" upper and with a suppressor it is extremely long and heavy.
Thanks

I have a 12.5" BHW barrel, but haven't had a chance to get any numbers. It is a nice, short package. Would be nice with a suppressor, even though it would end up equaling the length of a 22-23" barrel. I remember seeing a chart where a 450B was cut down from (I believe) 22" to around 13.5". I tried looking for it, but can't find it at the moment. The velocity loss wasn't that bad actually. Of course you will lose a bit more every inch you go shorter, so if you kept it at 12.5", it shouldn't lose a whole lot more. Plus, if you handload, you should get a little back.

MGM did a test like that on a encore bbl I think

That was it! It was from a 1:16 twist encore barrel, so velocity was a decent amount higher with factory ammo, but it didn't even lose 100fps going from 16" down to 13". So I would think at 12" you will lose about 100fps, but if you handload, you could get that back.

Interesting on a few calibers.


https://matchgrademachine.com/velocity- ... r-barrels/

The people trying to sell you something often leave out the important "YMMV" statement at the end of their test results, especially ammunition manufacturers and their claims to achievable velocity.

Hoot

Thanks everyone for the replies. Looks like a barrel in the 12 inch range will work just fine.