12.5" ar10?

[broylz]

Has anyone here dealt with a sbr'd 308? I have an itch to build a 12.5" ar10...

I know the ballistics are not up to the full power of the round but doing the math based on a 2250 fps found on another forum it still trumps the typical assault rifle calibers at just shy of 2k ft lbs.

 

[jasonfaz]

Yep. Aero Precision just threw some 10.5" 308 barrels on their site too. Mine is 12" but now I feel like a 10.5" might be in the works. Pretty easy to get full powder burn in under 10" of barrel with a 308. What specifically are you curious about when it comes to the 12"-ish 308 build?

 

[corym468]

Why anyone would build a sub 16" .308 is way beyond the basic fundamentals of logical thought IMO. But hell, to each his own. (You see what I did there Jason) HAHA

But seriously I don't understand an SBR AR10, you're still going to be as heavy or heavier than a 16" AR15. I'd seriously look at a 12" +- 0.5" Grendel, in an AR15. I'm about to join strategic edge, that seems to be right between us. I'd be happy to let you shoot my 16" Grendel there, one weekend, give you a chance to check it out.

 

[Skeld1]

Why anyone would build a sub 16" .308 is way beyond the basic fundamentals of logical thought IMO. But hell, to each his own. (You see what I did there Jason) HAHA

But seriously I don't understand an SBR AR10, you're still going to be as heavy or heavier than a 16" AR15. I'd seriously look at a 12" +- 0.5" Grendel, in an AR15. I'm about to join strategic edge, that seems to be right between us. I'd be happy to let you shoot my 16" Grendel there, one weekend, give you a chance to check it out.

Seems to me if you're not a reloader, and you don't want to spend your life picking up brass, the 7.62x51 is a lot easier to acquire than all these boutique calibers you guys love to talk about that fit in the AR15 platform. Perhaps I am uneducated though; I haven't spent much time studying the 6.8 SPC or the 6.5 Grendel.

 

[broylz]

I have read a lot of threads that end up saying that you lose so much power that you may as well shoot a 30-30 or whatever. Doing the math proves otherwise and I like the more compact size of the short barrel.

I was more hoping for a user feedback type of thread about the realities of muzzle blast or short barrels at longer range etc...

I find myself chasing the most power from the smallest package.

 

[Delta4-3]

Why anyone would build a sub 16" .308 is way beyond the basic fundamentals of logical thought IMO. But hell, to each his own. (You see what I did there Jason) HAHA

But seriously I don't understand an SBR AR10, you're still going to be as heavy or heavier than a 16" AR15. I'd seriously look at a 12" +- 0.5" Grendel, in an AR15. I'm about to join strategic edge, that seems to be right between us. I'd be happy to let you shoot my 16" Grendel there, one weekend, give you a chance to check it out.

You've never road hunted with a 16" .308!
I spent some time on a 13.5" SCAR and really enjoyed it. I'm considering an SBR .308 myself, with a can of course.
The helicopter crew that I am working with for the NV event uses all SBR .308's out of the bird because it's the best gun for the job.
The reason I want one is less technical. It's because I'm a spoiled American, and I get what I want regardless of whether or not I have a use for it, and I'm ok with that. That said, and SBR Grendel is in the works too.

 

[jasonfaz]

Why anyone would build a sub 16" .308 is way beyond the basic fundamentals of logical thought IMO. But hell, to each his own. (You see what I did there Jason) HAHA

But seriously I don't understand an SBR AR10, you're still going to be as heavy or heavier than a 16" AR15. I'd seriously look at a 12" +- 0.5" Grendel, in an AR15. I'm about to join strategic edge, that seems to be right between us. I'd be happy to let you shoot my 16" Grendel there, one weekend, give you a chance to check it out.

? Well, now that I've had a chance to cry it out after getting my feelings hurt....

Per OPs question, I also went with a shorty 308 for the power rather than the trajectory or range - for which there would be better choices. I can also reload it on the cheap.

Muzzle blast doesn't bother me with ear pro. I also shoot it about 75% of the time suppressed though. I was really on the fence when initially thinking about the compact 308 rig, but after some time on it I really like it. It's surprisingly easy to shoot, maneuverability is great and I can print decent groups out to 500. I haven't really tried shooting much further out than that and 90% of the time im shooting 300 and in with it. Great little 7 pound brush gun...

 

[corym468]

Seems to me if you're not a reloader, and you don't want to spend your life picking up brass, the 7.62x51 is a lot easier to acquire than all these boutique calibers you guys love to talk about that fit in the AR15 platform. Perhaps I am uneducated though; I haven't spent much time studying the 6.8 SPC or the 6.5 Grendel.

If you don't reload, I honestly don't see how you could even consider an SBR .308. As Jason has said you can make it work, but it won't be with factory ammo. At least not any factory loaded ammo I know of, whether it be hunting rounds or match.

Maybe mil surplus will work, I don't know, but you're not going to hunt or do any precision shooting with that stuff. So essentially you've just got a really expensive plinker.

However, any factory ammo on the market right now for the SAAMI Spec 6.5 Grendel, will work exceptionally with a 10.5" to a 24" Grendel with the proper gas system.

I have read a lot of threads that end up saying that you lose so much power that you may as well shoot a 30-30 or whatever. Doing the math proves otherwise and I like the more compact size of the short barrel.

I was more hoping for a user feedback type of thread about the realities of muzzle blast or short barrels at longer range etc...

I find myself chasing the most power from the smallest package.

If weight and factory ammunition isn't a factor than by all means, build yourself a sexy little .308. I look forward to seeing what you come up with.

You've never road hunted with a 16" .308!
I spent some time on a 13.5" SCAR and really enjoyed it. I'm considering an SBR .308 myself, with a can of course.
The helicopter crew that I am working with for the NV event uses all SBR .308's out of the bird because it's the best gun for the job.
The reason I want one is less technical. It's because I'm a spoiled American, and I get what I want regardless of whether or not I have a use for it, and I'm ok with that. That said, and SBR Grendel is in the works too.

I can't think of a better reason to build a gun.

 

[LRRPF52]

Seems to me if you're not a reloader, and you don't want to spend your life picking up brass, the 7.62x51 is a lot easier to acquire than all these boutique calibers you guys love to talk about that fit in the AR15 platform. Perhaps I am uneducated though; I haven't spent much time studying the 6.8 SPC or the 6.5 Grendel.

I will scour the earth like a crackhead who dropped an 8 ball when shooting .308 because I only really used Lapua brass. That crap often doesn't even hit the floor at the range if there are enterprising neighbors to your right. Often, the RSO's are the most vile offenders.

Here's a pic of a 12" AR10 next to a 16": http://i1100.photobucket.com/albums/g412/treadmarks69/2012-07-30192701.jpg

 

[hlee]

I will scour the earth like a crackhead who dropped an 8 ball when shooting .308 because I only really used Lapua brass. That crap often doesn't even hit the floor at the range if there are enterprising neighbors to your right. Often, the RSO's are the most vile offenders.

Here's a pic of a 12" AR10 next to a 16": http://i1100.photobucket.com/albums/g412/treadmarks69/2012-07-30192701.jpg

Caldwell Universal Brass Trap

You are welcome...

 

[LRRPF52]

I use brass catchers if feasible. You can make an expedient one with your patrol or boonie cap hanging over the scope.

 

[hlee]

I use brass catchers if feasible. You can make an expedient one with your patrol or boonie cap hanging over the scope.

Ejection of spent brass from my lr308 will blow right past my boonie- no matter how I position it. I tried it on several occasions. The only thing that I found worked with any reasonable success was a large towel draped over the scope and my head. Then I had hot brass ricocheting around under the rifle, off the bench, and off my heat sensitive skin. The catcher above works well but has to be positioned very close to the rifle. Too much wind and the catcher bumps on the rifle disrupting my sight picture. And, the brass will sometimes bounce right out of the trap. But, I worry less about losing brass with the trap so I shoot better, so it is staying for now.

As to the topic of the thread, I might try a sbr 308, but only If I were going to suppress it. Then again, I think I would go with a 300 black out in a lighter rifle, with less recoil, without giving up much in ballistics over the effective range... But, I do have a reloading setup in the garage.

 

[jasonfaz]

12.5" 308 next to 11" 5.56. Im in the middle of doing a little kryptek sumpin' sumpin' but for size comparison....there you go.


I genuinely don't notice weight difference with the same optic on each. Twice the pow pow in a very compact little set up. Once you throw cans on - considering 308 cans are traditionally longer than 5.56 - you end up with:


Hence the reason a 5.56 with dedicated can would be the most compact set up out there (or a 300 BLK - also getting the kryptek). With a 6.5 G you're going to be damn close to the length of a 308 using the longer cans. Yet, still won't be putting the energy on target that a .308 would. Within the effective range of each, you have only slight differences in trajectory and wind drift. The only downside I see is recoil, but again, shooting suppressed it ain't nothin but a G thang dawg. Let's face it, a shorty 308 is just gangsta...

 

[corym468]

......As to the topic of the thread, I might try a sbr 308, but only If I were going to suppress it. Then again, I think I would go with a 300 black out in a lighter rifle, with less recoil, without giving up much in ballistics over the effective range....

No comprende. :?

 

[Ledzep]

You know what... I just won't.

 

[jasonfaz]

No comprende. :?

I'm with you on that. The 300 BLK doesn't come close to a 308 regardless of what you do. Hell, the Grendel would destroy anything a 300 BLK will put on target regardless of barrel length (from an energy perspective). If the AR15 platform is what you're set on, and energy and external ballistics are top of the priority list, then 6.5G is what you want.

 

[Skeld1]

I will scour the earth like a crackhead who dropped an 8 ball when shooting .308 because I only really used Lapua brass. That crap often doesn't even hit the floor at the range if there are enterprising neighbors to your right. Often, the RSO's are the most vile offenders.

Here's a pic of a 12" AR10 next to a 16": http://i1100.photobucket.com/albums/g412/treadmarks69/2012-07-30192701.jpg

I understand if you're reloading for precision. But for a carbine role...why couldn't you get this 12.5" 308 SBR to run on XM80?

 

[banditbump]

Can you build an ar10 pistol? If so does anyone make pistol marked lowers? I think a short ar10 would be awesome in 338 federal or 375 steyr. That would bring some serious energy to the party and flatter trajectories than the 450 bush, 50 beowolf and 45 socom. you could use the new high bc bullets made for the cheytac and lapua and have subsonic rounds that bring alot more energy than the blackout.

 

[itieknots7]

I think this is where the LMT system really shines.

Throw on their factory 13.5" for hog hunting and other special situations and then run a 16" or longer when you need more distance. I doubt I would go shorter then 13.5" just so I could pin and weld a suppressor brake on it to keep it legal


Jason, Any recommendations for SBR reloads to maximize burn?