Why don't I see the 12.5" AR SBRs anymore?

[ARCHIVED THREAD] - Why don't I see the 12.5" AR SBRs anymore? (Page 1 of 2)

Posted: 1/9/2017 10:18:23 AM EDT

Don't get me wrong, they are certainly out there – and certainly being made. They have definitely faded in number, though.

The 12.5 inch SBR used to be hailed as the sweet spot, which has been replaced by the 11.5 inch. Why is that?

Posted: 1/9/2017 11:09:04 AM EDT

[#1]

Popularity and availability of suppressors would be my guess.

Posted: 1/9/2017 11:22:07 AM EDT

[#2]

I would rather have something 10.5" or 11.5" personally, especially since I'll be suppressing it which adds more length to the gun

Posted: 1/9/2017 12:25:47 PM EDT

[#3]

It's still a sweet spot.

Posted: 1/9/2017 12:27:21 PM EDT

[#4]

Quote History

Quoted:
I would rather have something 10.5" or 11.5" personally, especially since I'll be suppressing it which adds more length to the gun

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First two posts nailed it

Posted: 1/9/2017 12:34:53 PM EDT

[#5]

I have 2 of them. 10.5 loses too much velocity and is too short on dwell time shortening the life of the bolt. The 11.5 is a good compromise but the 12.5 midlength I have is the softest shooting rifle I own.

Posted: 1/9/2017 1:45:09 PM EDT

[#6]

Quote History

Quoted:
I have 2 of them. 10.5 loses too much velocity and is too short on dwell time shortening the life of the bolt. The 11.5 is a good compromise but the 12.5 midlength I have is the softest shooting rifle I own.

https://www.AR15.Com/media/mediaFiles/349595/20170109-113236-122509.jpg

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How did they balance with the specwar?

Posted: 1/9/2017 1:49:24 PM EDT

[#7]

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Quoted:

How did they balance with the specwar?

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With my specwar K or my omega, I don't have any issues at all. The one with the fixed stock is a lightweight barrel, so that helps balance it. With my specwar 762 they are front heavy, but so was my issued mk18 with a NT4 so I'm used to that.

Posted: 1/9/2017 1:55:14 PM EDT

[#8]

Quote History

Quoted:
I would rather have something 10.5" or 11.5" personally, especially since I'll be suppressing it which adds more length to the gun

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Most people have too short a barrel and too long a can.

Posted: 1/9/2017 2:35:04 PM EDT

[#9]

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Quoted:

Most people have too short a barrel and too long a can.

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7.5" barrel, Saker 556K. Pretty sweet!

Posted: 1/9/2017 3:02:13 PM EDT

[#10]

I really like my 12" AR. It is my go to gun... I also have a 10.5" AR which I like for different reasons. I really do want a K can though. I actually don't even own a 16" gun of any kind.

Posted: 1/9/2017 3:22:17 PM EDT

[#11]

Quote History

Quoted:

Most people have too short a barrel and too long a can.

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Quote History

Quoted:

Quoted:
I would rather have something 10.5" or 11.5" personally, especially since I'll be suppressing it which adds more length to the gun

Most people have too short a barrel and too long a can.

I have a Specwar K, not too long of a can

Posted: 1/9/2017 4:11:34 PM EDT

[#12]

I have a 12.5 6.8II. Sweet set up.

Posted: 1/9/2017 5:53:35 PM EDT

[#13]

I believe if you had more 11 to 11.75 inch rail options you would see more 12.5 builds.

I love the kac 10.75 and 11.5 barrel set up personally, if the URX 3.1 or 4 was 11.75 vs. 10.75 i believe you would see a lot more 12.5's

plus alot of guys have pinned 14.5's so for the $200 see 11.5 as getting shorter vs only gaining 2 inches via a 12.5 if i had to guess.

Posted: 1/9/2017 6:57:28 PM EDT

[#14]

Quote History

Quoted:
I believe if you had more 11 to 11.75 inch rail options you would see more 12.5 builds.

I love the kac 10.75 and 11.5 barrel set up personally, if the URX 3.1 or 4 was 11.75 vs. 10.75 i believe you would see a lot more 12.5's.

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Which came first, the chicken or the egg?

I have. 12.5" IDF retro gun almost done and I recently sold a 12.5" BA barrel
I'll have a 10.5" with a Trek, 11.5" with a SOCOM mini, 12.5" retro unsuppressed, 12.5" x39 with F1 .30cal, 13.7" p&w with kx5, 14.5" with p&w SOCOM mount, 16" with Specwar, & 18" mk12mod1 in process that will eventually wear an AEM5
I didn't need another 12.5"

Posted: 1/9/2017 8:05:01 PM EDT

[#15]

I have a F1 pending on a 12.5'' AR, I plan on building a reflex/otb F1 can for it.

Posted: 1/9/2017 8:22:50 PM EDT

[#16]

I see one every time I open my safe.

Posted: 1/9/2017 9:25:24 PM EDT

[#17]

Attached File

BCM Kino on Anderson F1 lower. Yucky right?
SakerK556. Great balance. Shoots 77's like a champ should.
And that is also why I got the 12.5. Just enough barrel to get the velocity I want for heavy pills.

Posted: 1/9/2017 9:37:26 PM EDT

[#18]

my 12.5" Noveske barreled rifle is my favorite "go-to" rifle and I use it 3-4 times for classes per year. I get close to 2930fps with xm193 so the hash marks in my scope align better out of my 12.5".

fatkid

Posted: 1/9/2017 9:38:49 PM EDT

[#19]

I wanted a 12" barrel but ended up with a 10.5" because PSA never had the 12" in stock.

Posted: 1/9/2017 11:19:34 PM EDT

[#20]

You rang?

Posted: 1/10/2017 2:19:02 AM EDT

[#21]

OP,
If it makes you feel better 12'' is the shorter AR we can legally buy here in Italy so its a common length here

Colt even make a special 6933 for italian market with the 12 barrel

http://armeriagb.it/prodotto.php?id=35004

Posted: 1/10/2017 12:56:31 PM EDT

[#22]

Quote History

Quoted:
OP,
If it makes you feel better 12'' is the shorter AR we can legally buy here in Italy so its a common length here

Colt even make a special 6933 for italian market with the 12 barrel

http://armeriagb.it/prodotto.php?id=35004

View Quote View All Quotes

View All Quotes

Quote History

Quoted:
OP,
If it makes you feel better 12'' is the shorter AR we can legally buy here in Italy so its a common length here

Colt even make a special 6933 for italian market with the 12 barrel

http://armeriagb.it/prodotto.php?id=35004

Interesting facts, cool

Quoted:
You rang?

http://i206.photobucket.com/albums/bb227/Gilenusx207/Weapons/IMG_1250_zpsfcqzooeo.jpg

Kino, right? Love it

Posted: 1/10/2017 2:55:51 PM EDT

[#23]

More Kino love

Posted: 1/10/2017 7:08:42 PM EDT

[#24]

I just sent psa an email the other day asking them to do another run of their 12.5 chf uppers. The one I have is my favorite ar of all time.

Unsupressed 12.5 is perfect. I can maneuver it in a pickup cab and I can reach out and open a hall door with the rifle shouldered.

Hits on ISPC target at 500 yards easy as pie.

Posted: 1/11/2017 8:37:32 AM EDT

[#25]

Meh, I just swapped the barrel on one of my 10.3" guns to 12.5". The handguard was just too short for my liking with a LAM + WML on the 10.3" gun.

12.5" BCM barrel with a 12" ALG EMR V2.

Eventually I'll pick up a Saker K to make it a little more manageable when the can is attached.

Attached File

Posted: 1/11/2017 10:30:04 PM EDT

[#26]

Here's a pair of them!

In the back is a 12.5" 6.5 Grendel and in the front is a recovering Kino (knocked the FSB off which made just the right room for an AEM5).

Posted: 1/11/2017 11:53:19 PM EDT

[#27]

Quote History

Quoted:
OP,
If it makes you feel better 12'' is the shorter AR we can legally buy here in Italy so its a common length here

Colt even make a special 6933 for italian market with the 12 barrel

http://armeriagb.it/prodotto.php?id=35004

View Quote

The next "clone" lol

Posted: 1/14/2017 10:29:09 PM EDT

[#28]

Because 10.5" is King for 5.56 SBR. If you are worried about velocity and effectiveness at longer distances you chose the wrong round for an sbr.

My sbr is 10.5" 1/8 wylde, lots of rounds mostly suppressed and not an issue at all.

I don't see a reason to go longer for an SBR.

Posted: 1/14/2017 10:31:01 PM EDT

[#29]

Quote History

Quoted:
I have 2 of them. 10.5 loses too much velocity and is too short on dwell time shortening the life of the bolt. The 11.5 is a good compromise but the 12.5 midlength I have is the softest shooting rifle I own.

https://www.AR15.Com/media/mediaFiles/349595/20170109-113236-122509.jpg

View Quote

So how many rounds through my 10.5" until my bolt fails?

What about my 16"?

Posted: 1/15/2017 12:17:48 PM EDT

[#30]

Quote History

Quoted:
Because 10.5" is King for 5.56 SBR.

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Only 10.39"

Guess that makes it the Prince of 5.56 SBRs

Posted: 1/15/2017 12:46:13 PM EDT

[#31]

Quote History

Quoted:

So how many rounds through my 10.5" until my bolt fails?

What about my 16"?

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Add a suppressor and dwell time goes back up... add an adjustable gas mechanism of one sort or another and the issue is resolved.

JPK

Posted: 1/15/2017 12:52:42 PM EDT

[#32]

Yeah like others have stated the 12.5 without a can is sweet ..... With a can meh

I would rather suppress a 10.5 or 11.5

Posted: 1/15/2017 1:19:08 PM EDT

[#33]

Quote History

Quoted:

So how many rounds through my 10.5" until my bolt fails?

What about my 16"?

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I'm
On our mk18s, for my unit, we were averaging between 3500 to 5000 before a bolt failure. Then crane tried to get us to use the one piece gas rings and that resulted in a bunch of FTF and FTE. By the time I got out, it still wasn't resolved (2014).

Posted: 1/15/2017 1:31:32 PM EDT

[#34]

12.5 master race checking in. I have 2x 12.5 guns and have parts for a third. They're very versatile and even with cans are light and maneuverable. Short 556 cans are the way to go. Trying to repurpose a 762 can on a short barrel isn't really ideal on anything bigger than 10"

Posted: 1/15/2017 2:24:34 PM EDT

[#35]

Quote History

Quoted:

I'm
On our mk18s, for my unit, we were averaging between 3500 to 5000 before a bolt failure. Then crane tried to get us to use the one piece gas rings and that resulted in a bunch of FTF and FTE. By the time I got out, it still wasn't resolved (2014).

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Suppressed or unsuppressed? Or a mix at what ratio? Adjustable gas? Adjusted gas?

Posted: 1/15/2017 3:37:54 PM EDT

[#36]

8.2" ...300BLK
10.5" ...5.56
12.5" ...6.8

Posted: 1/15/2017 5:37:32 PM EDT

[#37]

Quote History

Quoted:

Suppressed or unsuppressed? Or a mix at what ratio? Adjustable gas? Adjusted gas?

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Mix of both. NT4 when suppressed. High round count during force protection qualifying, but little use on full. There are several publications from crane on the issue we started having issued in 2011-12. Non adjustable, standard FSP, with a .068 gas port, as sent to us from crane. During a high tempo pre-deployment course we did, we had 3 different bolts shear lugs (out of 15 of us) after the second day of firing courses.

Posted: 1/15/2017 6:31:37 PM EDT

[#38]

Given your previous post, I suspected the answers you provided.

For civilian use, an adjustable gas system and a suppressor should resolve the issues, if they were the result of BCG speed and bolt bounce (as opposed to a bad lot of bolts, etc.)

In a thread somewhere here on Arfcom a range with select fire and semi auto AR platforms reported about a 10,000 round average life, iirc. The select fire weapons saw a lot of full auto use. No adjustable gas systems, range of upper lengths, some suppressor use.

JPK

Posted: 1/17/2017 6:37:27 PM EDT

[#39]

12.5" is the best inches

I love everything about it with the exception of how heavy my Noveske barrel is

I hated my 10.5", just wasn't a fan of how it felt
Nothing really wrong with 11.5" IMO

I actually took a hacksaw to the front of my rail to fit my F1 can a few months back

Posted: 1/17/2017 7:13:46 PM EDT

[#40]

Quote History

Quoted:
12.5" is the best inches

I love everything about it with the exception of how heavy my Noveske barrel is

I hated my 10.5", just wasn't a fan of how it felt
Nothing really wrong with 11.5" IMO

I actually took a hacksaw to the front of my rail to fit my F1 can a few months back

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Your posts always take me forever to read... 2 minutes of staring at your avatar, and then on to reading what you posted.

Posted: 1/18/2017 10:47:23 AM EDT

[#41]

Don't have one in 556 - yet. But have two 12.5" 6.8 and just got hte Form 1 stamp yesterday to install the 12.5" 308 Win barrel on my 2A Xanthos rig. I'm hoping for a violent hog and deer gun.

Posted: 1/23/2017 12:24:15 AM EDT

[#42]

Quote History

Quoted:
Given your previous post, I suspected the answers you provided.

For civilian use, an adjustable gas system and a suppressor should resolve the issues, if they were the result of BCG speed and bolt bounce (as opposed to a bad lot of bolts, etc.)

In a thread somewhere here on Arfcom a range with select fire and semi auto AR platforms reported about a 10,000 round average life, iirc. The select fire weapons saw a lot of full auto use. No adjustable gas systems, range of upper lengths, some suppressor use.

JPK

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I think ammo selection plays into it as well. Military guns are only going to be firing 5.56 pressure ammo whereas BV is probably using commercial spec .223 ammo. No doubt lower pressures would help to lengthen bolt life.

Posted: 1/23/2017 8:37:59 PM EDT

[#43]

Quote History

Quoted:

I think ammo selection plays into it as well. Military guns are only going to be firing 5.56 pressure ammo whereas BV is probably using commercial spec .223 ammo. No doubt lower pressures would help to lengthen bolt life.

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That would be true, for sure. Less chamber pressure, gas pressure through the gas tube, bolt speed... A little more dwell time...

JPK

Posted: 1/23/2017 11:00:27 PM EDT

[#44]

I'm shooting a 300 BLK so the extra barrel isn't really worth it. Going to get a suppressor and I don't really want that much more barrel.

When I get a 458, I'll probably get a 12" barrel if that makes you feel any better.

Posted: 1/24/2017 6:37:15 AM EDT

[#45]

Quote History

Quoted:
It's still a sweet spot.

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Agree. Shot a 3-gun match with mine Saturday, would not want it any shorter. Chased pigs around with a suppressor on it Sunday and wouldn't have wanted it any longer

Attached File

Posted: 1/24/2017 6:40:12 AM EDT

[#46]

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So how many rounds through my 10.5" until my bolt fails?

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A lot.

Posted: 1/24/2017 4:34:59 PM EDT

[#47]

Quote History

Quoted:

Agree. Shot a 3-gun match with mine Saturday, would not want it any shorter. Chased pigs around with a suppressor on it Sunday and wouldn't have wanted it any longer

https://www.AR15.Com/media/mediaFiles/326526/IMG-2192-132609.JPG

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I like this!

JPK

Posted: 1/24/2017 7:05:49 PM EDT

[#48]

I don't think 12.5" has ever been very popular. Everyone can agree that they have good ballistics but I think the reasons why they haven't been so popular:
1) long for a can
2) only 2" shorter than 14.5" and requires a stamp vs. a pinned 14.5"
3) and so because of #1 and #2 there are usually less barrels/rails in the 12.5" range.