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mustangfreek
23 November 2020, 22:37
Spitballing...So who’s running a 12.5-14.5” 308 AR?

I see mostly carbine gas on 12.5’s and a few 14” barrels. Seems brutal and a lot of talk about this. Seems a mid length 13.5-14.5 would be ideal..Seems easy enough by grabbing a 16” mid length and cutting it down

A shorty 308 Is intriguing me as my 18” build is just a heavy mofo and no deserving glass for it, as it got
A lot heavier then I wanted. 14lbs is no fun to pack around hunting/exploring.

Also ballistic wise , throwing 150’s at 2300’ish down range and 110/125’s at 2500 + will do a lot of damage

So who’s running a short barrel 308, and what have you done to tune it so it’s not bearing itself apart?

Pics are good too..[BD]

Jerry R
24 November 2020, 04:52
I have a Sig 716 CQB. That's a 12.5" Piston 308. Accurate, handles well (but heavier than a 16" AR in 5.56). I really like it, does everything I want a 308 to do. I need a short can though, the AAC 762-SD makes it way too long.
7658

mustangfreek
24 November 2020, 14:54
Thanks jerry

Good looking rifle, and as you say that can makes it look super long..lol

How’s the piston setup on the 308?

UWone77
24 November 2020, 19:10
A 12.5" 308 feels and looks like a 16" AR, its loud AF as well.

If you got a hole burning in your pocket, go for it.

7659

mustangfreek
25 November 2020, 05:43
So that’s a 12.5”, carbine gas system?

How brutal is it, assuming you only shoot it with a can?

Jerry R
25 November 2020, 05:58
Thanks jerry

Good looking rifle, and as you say that can makes it look super long..lol

How’s the piston setup on the 308?

Thanks. It is a short-stroke piston that is adjustable. Adjustment is done via an external knob. That's the thing sticking out the front (just under the front sight) with a hole in it. Positions are normal, suppressed, dirty, and off. Off obviously makes it a single shot.
Photo without the can mounted.
7660

UWone77
25 November 2020, 07:42
So that’s a 12.5”, carbine gas system?

How brutal is it, assuming you only shoot it with a can?

I've actually shot it more without the can. It's snappy for sure, but manageable. I wouldn't use it for my Go-To Home defense gun. If you don't want to lug around an 18" 308 AR this is definitely more compact, and still money if you're shooting for groups at 400-500.

mustangfreek
25 November 2020, 17:33
Cool.
Another question, so that is the 12.5” cmt rail?

As with the 12.5 barrel, it looks like a tight fit , especially with a can. Don’t want it so tight I can’t get a allen in there to adjust the adj block

Is it a true 12.5? The rail

UWone77
25 November 2020, 18:31
Cool.
Another question, so that is the 12.5” cmt rail?

As with the 12.5 barrel, it looks like a tight fit , especially with a can. Don’t want it so tight I can’t get a allen in there to adjust the adj block

Is it a true 12.5? The rail

11.9" Rail. He made it especially for 12.5" 308 Barrels.

In this case, (pictured) I used an AAC 51T deep socket FH. It recessed into the rail too much to get the can on. Swapped it out for the standard socket and the can was flush.

Also tried a Dead Air device before on it, flush as well. The 11.9" CMT is unique, as I've never seen another rail this size.

mustangfreek
26 November 2020, 15:53
Cool
Thanks for the info
Quick search turned up sold out everywhere on those cmt rails

UWone77
26 November 2020, 16:12
Cool
Thanks for the info
Quick search turned up sold out everywhere on those cmt rails

They're only done in limited runs. I'd just keep an eye on the CMT website as well as turn on the notification at Rainier.

mustangfreek
28 November 2020, 00:56
I’ve searched the interwebz and everyone is out of stock on 12.5 barrels

Seems like not quite a selection either( compared to 16ers and such)

Joelski
28 November 2020, 10:51
I'm kicking around a shorty upper too. Thinking 14.5" in 6.5 CM, which theoretically is still decent out to 1k yds. I have no need for a longer reach than 300 at my usual spot, but have been wanting to do a bolt action for the longer stuff when I occasionally get to go to a longer range. I guess the fact that it hasn't moved off the back burner all year is saving me money and telling me a don't really need it after all.

UWone77
28 November 2020, 11:16
I'm kicking around a shorty upper too. Thinking 14.5" in 6.5 CM, which theoretically is still decent out to 1k yds. I have no need for a longer reach than 300 at my usual spot, but have been wanting to do a bolt action for the longer stuff when I occasionally get to go to a longer range. I guess the fact that it hasn't moved off the back burner all year is saving me money and telling me a don't really need it after all.

I wanted to do a 16" 6.5 CM for shits... which barrel are you thinking of?

Mustang, there aren't a lot of 12.5" 308 barrels out there, because there isn't a ton of demand. They're making them on limited batches because they sit for awhile. I imagine now with the backlog/demand, everyone is just going to stock popular lengths until this all dies down.

mustangfreek
28 November 2020, 14:44
Ya I seen that rainier made a ultra match 12.5” a few years ago in there Gen 1 versions. But nothing since.

Just looked, they have a 10.5 nitride barrel.. too short though

A 14.5” 308 or creedmoor are about extinct also

Without buying longer and having it cut down, threaded etc

SINNER
28 November 2020, 15:47
Order a McGowan and be done. Worth every second of the wait.

mustangfreek
28 November 2020, 16:04
I forgot about them. But nothing shorter then 14” it says in their drop down menu

SINNER
28 November 2020, 18:30
Call them. They did a 12.5” .338 Fed for me about a year ago. And they just did a 13.7” .308 for a friend.

mustangfreek
11 December 2020, 03:51
Well to update

A 12.5” RA ultramatch and PRI fat boy gas tube was acquired for a deal to good to pass on. Lightly used as the old owner was tired of fireballs..[BD]

So...To be continued...[:D]

apmcdaniel
22 December 2020, 00:44
Well to update

A 12.5” RA ultramatch and PRI fat boy gas tube was acquired for a deal to good to pass on. Lightly used as the old owner was tired of fireballs..[BD]

So...To be continued...[:D]

I'm watching this thread, hot on your heels. I've been considering this for a couple years. I built a 16" 308 that turned out great on a 2A Armament Xanthos receiver set 2 yrs ago. Traded it for sewer work that was needed on the house. Guy loves it. Now I want to do a 12.5".


Sent from my iPhone using Tapatalk

mustangfreek
22 December 2020, 03:03
Haha cool.

I Just got my Yhm brake and slr 7, shims inbound and then just need a rail To put the upper together and see where it goes. Adjustable gas block and pri tube and starting with a h3 and Armalite buffer tube and spring ( A5 length ) Should be a good start.

Airborne_EWO
2 February 2021, 16:24
https://www.rainierarms.com/rainier-arms-ultramatch-308-barrel-11-5-contract-overrun/

This one looks interesting, 11.5 Rainier UltraMatch.

Wonder what contract they were produced for?

BoilerUp
2 February 2021, 20:07
LMT is going to make the 14.5" .308 piston MARS-H/MWS (the Estonian military rifle) available to the public this year.

Go to 20:09


https://youtu.be/YUxDuI5gI44?t=1209

mustangfreek
3 February 2021, 02:13
Nice. I wish.

UWone77
3 February 2021, 07:54
14.5" MWS Piston... I'm in.

mustangfreek
3 February 2021, 08:44
14.5" MWS Piston... I'm in.

Grab 2 , like you always do.. :) and I’ll make payments ...lol


What do you guess, $4500 ?

Joelski
3 February 2021, 13:40
Two digs in the first 30 seconds.

UWone77
3 February 2021, 16:53
Two digs in the first 30 seconds.

[:D]

Uffdaphil
3 February 2021, 18:46
Love the LMT vid. He could have edited out 20 minutes of hmms, but it wouldn’t have been as authentic. I have one splurge in the budget for this year (Besides a new truck.) and a short .308 may be it. But likely will be an ACE in 7.62x39. Unless they make more 5.45s before the hole in my pocket develops.

BoilerUp
3 February 2021, 19:47
Love the LMT vid. He could have edited out 20 minutes of hmms, but it wouldn’t have been as authentic.

It was a live stream, so...

It was the second one, so it's also worth going back and looking at January's if you are an LMT fan. First Monday of every month is what he's promising. I like the they are upping their outreach to the commercial / civilian market.

UWone77
4 February 2021, 10:14
I'm glad LMT is going more mainstream with the commercial side. Their stuff is so good, but under the radar with a lot of AR enthusiasts.

Still kicking myself for not picking up an ODG MWS or two or even the MRP receivers I had in my cart, but decided I didn't need them...