sub-sonic .308 load for Bushmaster 308 Hunter with TB 30-P1 suppressor

[Chadwick ATX]

I just picked up a Bushmaster .308 Hunter rifle. This is my first .308 and I have no experience loading for this caliber. Initially I will use the factory 20" barrel, but eventually I will downsize to a 16.5" barrel. I currently have a Thunder Beast 338BA silencer that I'll be using (simply because it's a spare suppressor that I have laying around that will do a reasonable job of suppressing this rifle), but I'm about 4 to 6 months away from getting the stamp back for my Thunder Beast 30-P1 suppressor that I purchased several months ago. I am looking at a Nightforce NSX 5.5-22X56 scope and I have a PVS-24 clip-on night vision that I'll also be using when the environment requires. I have had excellent results with Barnes Tipped TSX bullets that I load for my .338 Lapua and because of the tremendously awesome results that I've had with those bullets, I am predisposed to want to build a load around their .30 caliber counter-parts for my .308 rifle, but I am open to any suggestions. So I'm curious:

Do any of you use the Bushmaster 308 Hunter, and how do you like it?

Is anybody loading for this rifle, or any AR-10 platform chambered for .308 and do you have input about this?

What powder are you guys using for your .308 reloading? What powders for Supersonic vs Subsonic loads?

Have you run into issues with the cartridge being too long to fit in the magazine? (I have this problem with my .338 Lapua so I shoot it like a single shot)

Do you have a free floating handguard with picatinny rails on top and at least a little on the sides? What make/model handguard are you using?

Any other input or thoughts?

 

[rjacobs]

Just so you know the gun wont cycle subsonic's. I have never seen an AR308 cycle subsonics, trust me I have tried. MAYBE if you heavily modify the gun it would.

 

[mallrat]

Just a thought, how heavy of a projectile are you planning on using? 300 blackout seems like an easier solution unless you're going over 220 gr. or so, IMO.

E.T.A. That's for subsonics, not applicable to supers.

 

[Chadwick ATX]

Just so you know the gun wont cycle subsonic's. I have never seen an AR308 cycle subsonics, trust me I have tried. MAYBE if you heavily modify the gun it would.

A concept I had not considered. I definitely don't need to go subsonic as I can think of few environments where that would actually help. In my experience even the subsonics make enough noise to scare off a pack of hogs with the first shot. Thanks for the input, I won't pursue subsonic.

 

[Chadwick ATX]

Just a thought, how heavy of a projectile are you planning on using? 300 blackout seems like an easier solution unless you're going over 220 gr. or so, IMO.

E.T.A. That's for subsonics, not applicable to supers.

150 to 180 gr. depending on input that I get. I like heavy bullets. In my experience there's no replacement for displacement. I'm sure there are plenty of examples of why that's not true which is why I'm here asking before purchasing bullets.

 

[rjacobs]

You wont know what your gun likes until you get it and try a bunch of stuff.

My MWS doesnt shoot 175's that great even though it should and its a very popular 308 bullet. The gun much prefers 155g stuff.

 

[Myanmar Shave]

Just so you know the gun wont cycle subsonic's. I have never seen an AR308 cycle subsonics, trust me I have tried. MAYBE if you heavily modify the gun it would.

Mine does! LR-308 14" w/AAC Cyclone. 24 grains 4350 powder under a 220 grain 30-30 bullet. I did several mag dumps without a hiccup yesterday. YMMV

 

[Arbiter]

Mine does! LR-308 14" w/AAC Cyclone. 24 grains 4350 powder under a 220 grain 30-30 bullet. I did several mag dumps without a hiccup yesterday. YMMV

What twist rate is your barrel? And are you running an actual stamped SBR, or just pinned and welded?

 

[mtrmn]

Mine does! LR-308 14" w/AAC Cyclone. 24 grains 4350 powder under a 220 grain 30-30 bullet. I did several mag dumps without a hiccup yesterday. YMMV

24 gr of 4350 is SUB sonic??

 

[K_4c]

I roll this load data for both my semi and bolts... 4.1 mils to hit at a 100m

http://m.youtube.com/watch?v=cEc5jVFmXlo

Start at 13 gr of Trail boss and work down....

 

[Myanmar Shave]

24 gr of 4350 is SUB sonic??

YouTube

 

[blcouch]

YouTube

"This video is private."

What was it going to show?

 

[CK_32]

150 to 180 gr. depending on input that I get. I like heavy bullets. In my experience there's no replacement for displacement. I'm sure there are plenty of examples of why that's not true which is why I'm here asking before purchasing bullets.

The heavier the bullet the less speed you will have to give it to keep going. Think of 45 vs 9mm.. Lighter bullets need more speed to keep momentum at distance. Heavier bullets have more mass to help keep its initial momentum. But as far as I've read 175's don't like transonic or subsonic all that much. But I know a lot of guys who suppress prefer 175+ again due to the ability to have slower muzzle velocity but still hold momentum to get a little more distance but keep the MV down.

Just so you know the gun wont cycle subsonic's. I have never seen an AR308 cycle subsonic, trust me I have tried. MAYBE if you heavily modify the gun it would.

If a adjustable gad block is heavily modified. You need to tweak the load to fire just under transonic. There are ways to do it I see a decent amount of guys cycle suppressed now. Also a JP LM BCG with a lighter buffer spring. Again not heavy as in the mod department in my book. Just simple plug and play.

 

[mtrmn]

YouTube

OK the video will play now. Is the gun modified in any way to make it cycle subsonics? I have 4350, just need to get some 220's and try this out. I just was amazed that such a "heavy" charge of 4350 would actually stay under the speed of sound. I've only used Trail Boss, and heard of using pistol powders like Unique etc.

 

[Myanmar Shave]

The only modification is the Fulton Armory side charging handle which adds a little weight to the bolt carrier group. No gas port enlargement or anything like that. The 30-30 style round nose bullet is the trick. It has a huge bearing surface that allows the bullet to stabilize. You will never get it to work with a SMK 220 or anything like it.

 

[K_4c]

^ bearing surface is critical for stabilization.

 

[steelringer]

The only modification is the Fulton Armory side charging handle which adds a little weight to the bolt carrier group. No gas port enlargement or anything like that. The 30-30 style round nose bullet is the trick. It has a huge bearing surface that allows the bullet to stabilize. You will never get it to work with a SMK 220 or anything like it.

What twist barrel is that your running to stabalize the 220's?

 

[mtrmn]

OK - a subsonic load that would actually cycle my AR 308 would renew my pursuit of subsonic loads. Got to get some 220RNs now.

 

[No1]

Mine does! LR-308 14" w/AAC Cyclone. 24 grains 4350 powder under a 220 grain 30-30 bullet. I did several mag dumps without a hiccup yesterday. YMMV

Thank you. now I know what to do with that 2# of powder.

 

[Myanmar Shave]

What twist barrel is that your running to stabalize the 220's?

It is a standard DPMS M4-style 10 twist barrel that I had cut down.