338 subsonic round
 

Any intrest in a 338 subsonic round for the AR15? The 338 spectre & Whisper brls are very expensive. Just wondering if there would be any interest. IM if interested.

I have a 300 and want a bigger cal like maybe a 458 socom :grin:

Dont forget the 50AE! The 500g XTPs are easy to run at subsonic speeds. I am also working on a subsonic 458 based off the 50AE & designed around a 9-10" brl. I was just looking at any intrest in a 338 based round that dies & brass are inexpensive & my brls would run the same as the 300W:smile:

bigger?
 

I've got 458 socom , 50 EBG and 510 Whisper that I shoot subsonic...lots of fun.

What kind of twist are you thinking for the 338?

Ive picked up a 8twist Shilen. I want to be able to shoot a variety of bullets & velocitys like the 300whisper. I heard SSK uses an 8twist for their 338Whisper on the BR case. Im using the AR15 308 dia bolt from MGI(for the socom) Bolt should yield 35K psi. More then enough to give me what I want out of the 44AMP brass I am using. Dies can be had for $30. Seems like a way to get into the 338 game without spending a fortune. Here is a pic of my idea(left) next to the 338Spectre(right).
http://i53.photobucket.com/albums/g61/ron458/338.jpg

Here's another option for a subsonic AR-15. This 600 grain bullet will shoot subsonic from a 16" Alexander Arms Beowulf rilfe with the standard 16" twist. The bullet is available from
http://www.alliancearmament.com/thebeast.aspx

http://www.alliancearmament.com/imag...tail/600gr.jpg

If I was going to bulld a subsonic 338 AR it would be a 338/7mmBR in a DPMS LR-308. 300 grain 338 SMKs could shoot from the magazine.. Will the 338 Specter shoot heavy low drag bullets from a AR-15's magazine? If not why not just use the 300 Whisper?

A shorter case on any subsonic round would be best to keep load density up. The 50AE would fill this better than the 50b for that reason. As for the 458, shorter is better again. Here is the 458 Short with 350, 405, & 600g projectiles. I designed this around 9-10" brls. She will get a workout thursday time permiting:uzi2:
http://i53.photobucket.com/albums/g6...58short005.jpg

As for the 338, with the MGI bolt being released soon I am planing on running the 338BR case & just down load for the subsonic 338.

Ron458 - What are the brands/models of each of the bullets shown in the picture you just posted? Are those standard 458 Socom cases?

For spitzer bullets I'd agree on the 50 AE giiving better load densities than the 50 Beowulf, but using the 600 grain RBT shown above seated to standard 50 Beowulf OAL the load density just right for subsoinic use. The long shank and short ogvie engages the rifling with little jump. The rebated boattail is mostly to use up case capacity and add weight rather than giving higher BCs. It's not a partularly low drag desing though it's mass makes the BC higher than other bullets which will feed though an AR-15 magazine. Yes, it could be used with a 50 AE case in a custom chamber but not in a SAAMI spec 50AE chamber. It was designed specifically for the 50 Beowulf standard chamber and 16" (length and twist) barrel for use in magazine fed AR-15s. I wouln't consider it for a subsonic bolt action. For that i'd use the cartridge next to the far right below. It's 582 gn with a subsonic G1 BC greater tnan 1.0 and will feed nicely from a Rem 700 LA magazine. Its case capacity is close to the larger diameter but shorter 458 Socom next to it. For that you could probably rebarrel a Browning or a Cobb MCR to shoot it if a semi-auto is more desirable. Perhaps even an M1 Garand.

The cartridges left to right are 223 rem, 458 Socom with 280 gn Lehigh flat base, 338/7mmBR with 245 gn Lehigh boattail, 308 Win, 458 Socom with 582 gn Lehigh boattail, 458x2 American with 582 gn Lehigh boattial, and a 7mmStW. The end and middle cartridges are just for size comparison..


http://i174.photobucket.com/albums/w...ics/lehigh.jpg

350g Hornady SP, 405 Rem SP & I belive the last 2 are 600g Hornady FMJ. I have had these sitting around for some time now. You can still get the 550g FMJs. The cases are 50AE & the rebated rim is the 50B shortened to 50AE length.

Why the 44 AMP as compared to either the 10mm Magnum or the 7mm BR? Can you give specifics on the economies (brass price, die price, etc)? I'm thinking of building a .338 Spectre. Thanks.