450Bushmaster.net

Eventually I'm wanting to get another upper of a dif cal. I've been tossing around 6.5mm,7mm,.338 and .375 Well out of them all I'm leaning towards the .375 It's available in good weights with decent BC's. Now I've also been trying to decide what case to use for this project. I thought about a cut off .308 a necked down 450b and of course a necked up 25WSSM. I'm leaning towards the WSSM due to the powder capacity. so what ya think about a .375WSSM ar15? I would probably have Dtech build it for me.

I feel your pain. I made my new baby a Grendel. She is gonna be a sweetie.

Stealthshooter wrote:Eventually I'm wanting to get another upper of a dif cal. I've been tossing around 6.5mm,7mm,.338 and .375 Well out of them all I'm leaning towards the .375 It's available in good weights with decent BC's. Now I've also been trying to decide what case to use for this project. I thought about a cut off .308 a necked down 450b and of course a necked up 25WSSM. I'm leaning towards the WSSM due to the powder capacity. so what ya think about a .375WSSM ar15? I would probably have Dtech build it for me.

Personally, I'd like either the .338 Federal or have Mike make you a .358 Winchester barrel and extension for your AR-7.62 variant. Now we're talkin!
Seriously, there are some fine .338 bullets out there.

Hoot

The problem I was running into with the .338 bullets was length in the weights I'm wanting to shoot. Sierra .338 250 grain game king is 1.425"" long a Sierra .375 250 grain game king is 1.183" long and still has a .353 BC

Stealthshooter wrote:The problem I was running into with the .338 bullets was length in the weights I'm wanting to shoot. Sierra .338 250 grain game king is 1.425"" long a Sierra .375 250 grain game king is 1.183" long and still has a .353 BC

That's odd as Midway lists the .338 250gr Game King as having a BC of .565. The .338 215gr Game King, which is 1.27 inches long has a BC of .485 and the .338 225gr Pro Hunter has a BC of .462 at 1.28 inches length. Don't write off the .338 Federal too soon.

Hoot

My goal is to shoot a 250 grain bullet with a decent BC. I'd love to have a .338 Federal but I don't want to go to an AR10

The 338 Spectre could launch those bullets out of a AR-15 platform. It uses a resized 10mm Magnum and a 6.8SPC bolt face. The disadvantage is you would probably load to subsonic velocities, which would mean you wouldn't have the ballistic advantage of higher velocities.

I have a 300 Fireball(Whisper), the brass conversion takes some time, but it sounds like it is a little faster and easier to form 338 Spectre brass from 10mm.

Here's some more info on it:
http://www.ar15.com/content/page.html?id=559

That does look like an interesting round! The only issue like you said is it's not getting the velocities I'm looking for. I may be dreaming on what velocities I'm wanting to run but I figured if I could get the .375WSSM up to the 2400-2500fps range with a 250 grain bullet it would make a pretty formidable weapon and also something not everyone has.

Here is a ballistic chart using the 250 grain Sierra game king with a .353 BC running at 2500fps.

http://www.hornady.com/cgi-bin/ball10.c ... =Calculate

Stealthshooter wrote:Here is a ballistic chart using the 250 grain Sierra game king with a .353 BC running at 2500fps.

http://www.hornady.com/cgi-bin/ball10.c ... =Calculate

What you're proposing is a cartridge with the characteristics of a 376 Steyr, which is rated at more recoil than the 300 Remington Ultra Mag. That caliber challenges even a sturdy steel bolt action. Somehow, I doubt an AR15 platform will takes that kind of abuse. Think 450 Bushmaster recoil. Now double it. That's a lot of punishment. Then again, two years ago, I would never have dreamed that an AR15 platform could handle the punishment of a 450 Bushmaster either. So, who's to say?

Hoot