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rxer311
11 March 2018, 10:42
For whatever reason ever since I built my 10.3" SBR I have wanted t 12.5" carbine. I am starting with a pistol and plan on doing another form 1 for this lower. I finally committed to the build but need a bit of input in a few areas.

First thing I am looking for is my hand guard choice. There are very few choices out there when it comes to maximizing rail space for a 12.5" build. I am leaning in 1 of 2 directions at the moment. First is to run an SLR 11.5" Solo rail leaving minimal barrel space between my rail and SiCo Saker. The other choice I was debating was running a MI 12" suppressor compatible rail (which measures 12.65") which would leave my can slightly recessed under the hand guard. I am kind of leaning in this direction, however, I have concerns about being able to actually fire the rifle without the suppressor attached. I plan on using a Saker mount which looks to have a bit over an inch of area before the prongs open up. With the device mounted it seems like it should work, but I don't know for sure. If anybody has a 12.5" setup with pics, with either type of these options, that would be helpful.

Second thing. Gas block. My other SBR has a pinned gas block that is not adjustable. It is overgassed, but I have been able to tame it with a heavier spring and H buffer. I don't have any problems with gas in my face. I am thinking of doing an SLR adjustable block on this build with a clamp on style block. What is the consensus on this type of clamp on block? Good to go for hard use? Or, should I just get a set screw type and have it pinned?

Thanks guys!

Edit...barrel came today. Coming along nicely.

https://i.imgur.com/6UC45FW.jpg

alamo5000
11 March 2018, 10:53
SLR makes great blocks but on a 12.5 I would think it's easier to tame gas wise than a 10.5.

If you really want to adjust it you can fine tune it of course. I set my SLR adjustable blocks to run suppressed and non suppressed and haven't touched em since. You still might have to tune it with buffers and springs but I would think you could tune a 12.5 upper a lot easier on the backend rather than a gas block.

Personally I'm not a fan of clamp on blocks but that's just me.

As for barrels and hand guard choice someone here pointed out that one barrel manufacturer leaves their 12.5" barrels slightly longer so it will be easier to get a rail fit.

I forgot which company that is but it would open up more options for you.

UWone77
11 March 2018, 10:57
Good timing.

I'm doing a 12.5" upper right now with a 11.5" Cross Machine Tool HDX Handguard.

fledge
11 March 2018, 11:38
Rxer311, what barrel you going with? I hear VSeven will sell a reduced gas port 12.5 if you call in the order. That would come with pinned block.

Id go with a dimple block if the barrel is dimpled. It indexes the block over the gas block without guess work.

I run a SMOS 12 with my 12.5 barrel.

UWone77
11 March 2018, 11:51
I run a SMOS 12” with my 12.5 barrel.

I've got a Faxon 12.5" on a 12" SMOS handguard as well. The muzzle device is slightly recessed in the handguard, but clears any ports on the brake.

gatordev
11 March 2018, 13:05
I'm a huge fan of the 12.5" setup and thanks to fledge (I believe), one of my two uppers is a V-Seven barreled setup. Obviously your objectives may be different than mine, but here's what I came up with when I first built a carbine and then wanted a similar setup for a Mini-Recce.

For the carbine:

- I didn't want a "lightweight" build, but wanted to keep the weight down across the rifle
- It was planned to be a competition/class gun that would run a RDS and have a light for a night class/whatever work
- Was suppressor friendly
- I wanted a quad rail because I like quad rails, but there was some flexibility to that. More importantly, I wanted to maximize weak-hand position to get it as far forward as I could for comfort

At the time, a 10.75" rail was about all I could come up with. The finalist rails were a KAC URX 2, KAC URX 3.1, or a Centurion Arms 10". I went with the URX 3.1, but the CA rail is actually the same length as the bottom of the KAC rail. The top of the KAC rail extends out the .75". I know you want longer, but those were my options at the time. I also went with a CA 12.5" barrel. I was already a happy CA customer with my CA MK12 and the 12.5" has not disappointed with good ammo. Gas when suppressed isn't really an issue. Pic for attention...

https://farm5.staticflickr.com/4195/34747629912_4fde570f92_b.jpg

Then came the Mini Recce...

- Wanted an accurized carbine
- Wanted minimal gas
- Wanted a quad rail for bipod mounting but still leaving room to "perch" the rail on a barricade (URX 3.1 fails at this, even on my SR-25)
- Wanted to keep the weight down otherwise

I ended up going with a URX 2 and a V7 barrel which has just been a lights out shooter (I have a thread here somewhere). As fledge mentioned, you can also get a reduced gas port for his 12.5" and 14.5" barrels, which I did. Unsuppressed, it's like shooting a loud .22. Suppressed, it feels like shooting a 14.5" carbine (a little bit of a push and recoil impulse). Again, sounds like you have more options to get a longer rail now, especially if you don't want a quad. Pic for attention...

https://farm5.staticflickr.com/4232/35332905600_b95a45f729_b.jpg

I will add that this would all be solved if we had access to a GL/SSC rail...

rxer311
11 March 2018, 13:27
Rxer311, what barrel you going with? I hear VSeven will sell a reduced gas port 12.5 if you call in the order. That would come with pinned block.

Id go with a dimple block if the barrel is dimpled. It indexes the block over the gas block without guess work.

I run a SMOS 12 with my 12.5 barrel.

I have a KAK industries 12.5" carbine barrel on order. It is not dimpled, however, I like how clamp on blocks will give even pressure around a barrel rather than being pushed from one side with set screws. I actually think it is the more foolproof way to secure a block.

Link to barrel...

https://www.kakindustry.com/ar-15-parts/upper-parts/barrels/5-56-mm/12-5-inch/contract-556-125-inch-carbine-melonite-barrel

UWone77
11 March 2018, 13:30
I have a KAK industries 12.5" carbine barrel on order. It is not dimpled, however, I like how clamp on blocks will give even pressure around a barrel rather than being pushed from one side with set screws. I actually think it is the more foolproof way to secure a block.

Link to barrel...

https://www.kakindustry.com/ar-15-parts/upper-parts/barrels/5-56-mm/12-5-inch/contract-556-125-inch-carbine-melonite-barrel

Personally, pinning is my only method.

Set screws suck without a dimple. I can't believe everyone doesn't dimple their barrels from the factory.

fledge
11 March 2018, 13:37
gatordev, glad to inspire. Those rifles are hot.

The CA 12.5 barrel is now unobtanium. Wish I had grabbed one. I hear they are ported very well. Wish I had known VSeven could reduce the port back when I ordered mine.

fledge
11 March 2018, 13:38
I have a KAK industries 12.5" carbine barrel on order. It is not dimpled, however, I like how clamp on blocks will give even pressure around a barrel rather than being pushed from one side with set screws. I actually think it is the more foolproof way to secure a block.

Link to barrel...

https://www.kakindustry.com/ar-15-parts/upper-parts/barrels/5-56-mm/12-5-inch/contract-556-125-inch-carbine-melonite-barrel

Is your barrel and ammo and skill that perfectly in line with the moon and stars that you would notice a difference between a dimple and clamp version?

rxer311
11 March 2018, 13:47
I am not concerned about the accuracy potential, I just feel that a clamp on block is a more secure attachment method.

Probably just send it to Axlnut to pin a block for me though.

UWone77
11 March 2018, 14:45
gatordev, glad to inspire. Those rifles are hot.

The CA 12.5” barrel is now unobtanium. Wish I had grabbed one. I hear they are ported very well. Wish I had known VSeven could reduce the port back when I ordered mine.

You may see a come back on those at some point.

rxer311
11 March 2018, 16:21
I think I am going to try the MI suppressor compatible rail and see how far recessed it goes.

I am thinking a 12.5" barrel with .6" for threading, so the muzzle device would start at 11.9". The rail is 12.65" so that is 0.75" of the muzzle device recessed. The mounting point for the suppressor is 0.25" from where the muzzle device meets the shoulder of the barrel and the tines of the FH start at 1.25". This means that the suppressor would be recessed .5" when mounted and the FH should clear the hand guard by 0.5" when the suppressor is not mounted.

Does 0.6" for threading sound right? If so, I think this setup will work well.

UWone77
11 March 2018, 17:37
I'm a huge fan of the 12.5" setup and thanks to fledge (I believe), one of my two uppers is a V-Seven barreled setup. Obviously your objectives may be different than mine, but here's what I came up with when I first built a carbine and then wanted a similar setup for a Mini-Recce.

For the carbine:

- I didn't want a "lightweight" build, but wanted to keep the weight down across the rifle
- It was planned to be a competition/class gun that would run a RDS and have a light for a night class/whatever work
- Was suppressor friendly
- I wanted a quad rail because I like quad rails, but there was some flexibility to that. More importantly, I wanted to maximize weak-hand position to get it as far forward as I could for comfort

At the time, a 10.75" rail was about all I could come up with. The finalist rails were a KAC URX 2, KAC URX 3.1, or a Centurion Arms 10". I went with the URX 3.1, but the CA rail is actually the same length as the bottom of the KAC rail. The top of the KAC rail extends out the .75". I know you want longer, but those were my options at the time. I also went with a CA 12.5" barrel. I was already a happy CA customer with my CA MK12 and the 12.5" has not disappointed with good ammo. Gas when suppressed isn't really an issue. Pic for attention...

https://farm5.staticflickr.com/4195/34747629912_4fde570f92_b.jpg

Then came the Mini Recce...

- Wanted an accurized carbine
- Wanted minimal gas
- Wanted a quad rail for bipod mounting but still leaving room to "perch" the rail on a barricade (URX 3.1 fails at this, even on my SR-25)
- Wanted to keep the weight down otherwise

I ended up going with a URX 2 and a V7 barrel which has just been a lights out shooter (I have a thread here somewhere). As fledge mentioned, you can also get a reduced gas port for his 12.5" and 14.5" barrels, which I did. Unsuppressed, it's like shooting a loud .22. Suppressed, it feels like shooting a 14.5" carbine (a little bit of a push and recoil impulse). Again, sounds like you have more options to get a longer rail now, especially if you don't want a quad. Pic for attention...

https://farm5.staticflickr.com/4232/35332905600_b95a45f729_b.jpg

I will add that this would all be solved if we had access to a GL/SSC rail...

Beautiful gun gator. Dude you read my mind.

I'm planning a 12.5" Mini Recce. SBR'ed a Cross Machine Lower, going with SMOS 12.5" I had on a Shilen Blank. Will go with the 11.5" CMT Handguard and probably a Dead Air KeyMo mount for whenever my Sandman K gets approved.

Probably throw my EOtech VUDU 1-6 optic on it.

Dstrbdmedic167
11 March 2018, 22:09
Good timing.

I'm doing a 12.5" upper right now with a 11.5" Cross Machine Tool HDX Handguard.Did not realize they made an 11.5. I habe the perfect barrel for that rail to use with the liner comp. Hmm [emoji848][emoji848][emoji848]

Sent from my SM-N950U using Tapatalk

UWone77
11 March 2018, 22:41
Did not realize they made an 11.5. I habe the perfect barrel for that rail to use with the liner comp. Hmm [emoji848][emoji848][emoji848]

Sent from my SM-N950U using Tapatalk

So far I understand it to be a limited run.

Dstrbdmedic167
12 March 2018, 05:24
So far I understand it to be a limited run.Well that explains that. Is that the Matt helm version or another limited run?

Sent from my SM-N950U using Tapatalk

gatordev
12 March 2018, 05:37
Beautiful gun gator. Dude you read my mind.

I'm planning a 12.5" Mini Recce. SBR'ed a Cross Machine Lower, going with SMOS 12.5" I had on a Shilen Blank. Will go with the 11.5" CMT Handguard and probably a Dead Air KeyMo mount for whenever my Sandman K gets approved.

Probably throw my EOtech VUDU 1-6 optic on it.

The MR now wears a NF 2.5-10 with the T1 offset that's in that pic above. I was going to put the ATACR 1-8 on it, but I think that will go somewhere else (whenever it might arrive). The 2.5-10/T1 combo solves most what I need for that rifle, and the reticle is so much more useful than the thick ones on the MK6.

SINNER
12 March 2018, 12:03
My favorite SBR length. Even cut down a SCAR barrel rather than use a factory 10”.

5063

One of these decades I’ll build around this 12.5”

5064

EO3
12 March 2018, 12:22
So far I understand it to be a limited run.

Would really love an 11.5" CMT rail. Any idea how to get one UW? Also working on getting a 12.5" build together myself and would much prefer their rail over a MI or SLR.

rxer311
12 March 2018, 13:58
Glad I am not the only one to have the 12.5" itch. It doesn't seem to be a popular length as barrel options are limited. I really wanted to go Noveske Crusader for this gun, but right now I don't have a Noveske budget.

DeviantLogic
12 March 2018, 15:53
I went with a 2A Armament SR Rail on my 12.5". Their 12" rail was 11.82" actual. I'm using a Saker on it as well. There's roughly a quarter inch between the suppressor and the rail. If there's a rail you like that's 12" actual, then I think that might be the perfect length.

fairlanericky
13 March 2018, 10:41
How about a Samson Evolution rail? They have 12.37" that is suppressor friendly(1.56" I.D.).



Ric

UWone77
14 March 2018, 12:27
The 11.5" on a 12.5" SMOS Barrel.

5071
5072

rxer311
14 March 2018, 15:12
Thanks for the pic. 11.5 seems to be a good length without tucking.

rxer311
14 March 2018, 16:17
Barrel came today. Its coming along...

https://i.imgur.com/6UC45FW.jpg

rxer311
19 March 2018, 19:26
So I found a deal on a 12.5" Noveske SS. Got it used with only 300 rounds through it. Going that route.

rxer311
19 March 2018, 19:26
The 11.5" on a 12.5" SMOS Barrel.

5071
5072

Any idea on how to get this?

UWone77
19 March 2018, 19:48
Any idea on how to get this?

I know you and E03 wanted one. Let me ask Jeff. This is known as affectionately as the Matt Helm rail, as he requested they make one for his 12.5

rxer311
19 March 2018, 19:56
Group Buy! [:D]

alamo5000
19 March 2018, 20:02
I know you and E03 wanted one. Let me ask Jeff. This is known as affectionately as the Matt Helm rail, as he requested they make one for his 12.5

While you are asking can you ask them to make runs of suppressor friendly handguards? 8.2", 8.7", 9.7", etc.

Right now SLR is the only game in town as far as I know in that niche. Don't get me wrong--I like SLR---but I would like more options for a tight suppressor fit.

EO3
19 March 2018, 20:11
I know you and E03 wanted one. Let me ask Jeff. This is known as affectionately as the Matt Helm rail, as he requested they make one for his 12.5

I messaged Matt and it sounds like maybe CMT is going to produce them in a small quantity? I like that his doesn't have a full top rail though, and FDE is always nice too [:D]

SINNER
19 March 2018, 20:20
$69.99?

UWone77
19 March 2018, 20:40
I messaged Matt and it sounds like maybe CMT is going to produce them in a small quantity? I like that his doesn't have a full top rail though, and FDE is always nice too [:D]

That was cerakoted himself, and then sent back for re-laser engraving. Did a few myself.

Stickman
19 March 2018, 20:55
This would look great on a Noveske Crusader Barrel.

rxer311
20 March 2018, 04:39
This would look great on a Noveske Crusader Barrel.

Well, when I get it together you can take pictures of it, okay? [:D]

fledge
20 March 2018, 06:03
Id be in for the 11.5 handguard with the full top rail.

UWone77
20 March 2018, 07:18
Just talked to Jeff at CMT.

Full Top rail 11.5" HDX handguards will be available on the website later this week when he has the time. No word if these will be a limited run or if they will make more in the future. If you want one, I'd suggest you get one.

fledge
30 March 2018, 11:01
To add to the info:

12.5 VSeven barrel. SMOS 12 inch handguard. Dead Air device.

https://i.imgur.com/1ryu7KE.jpg

UWone77
31 March 2018, 05:42
To add to the info:

12.5” VSeven barrel. SMOS 12 inch handguard. Dead Air device.

https://i.imgur.com/1ryu7KE.jpg

Looks good. I forgot I had a 12.5" SMOS upper until I saw yours.

fledge
31 March 2018, 06:58
The SMOS barrels are dynamite. I would have gone they route if I didnt have the VSeven.

This was their last 12 hybrid rail. Bugged Eric forever and they finally made a few.

UWone77
31 March 2018, 07:46
The SMOS barrels are dynamite. I would have gone they route if I didn’t have the VSeven.

This was their last 12” hybrid rail. Bugged Eric forever and they finally made a few.

SMOS barrels should be dynamite. Same guy that turns RA UM's does them on the same blanks. [:D]

fledge
31 March 2018, 09:15
SMOS barrels should be dynamite. Same guy that turns RA UM's does them on the same blanks. [:D]

Now thats good intel. ;)

fledge
31 March 2018, 10:30
https://i.imgur.com/usRY2Zf.jpg

UWone77
15 April 2018, 12:44
OG Noveske 12.5" Crusader/VLTOR VIS Upper

5213

Former11B
15 April 2018, 13:42
OG Noveske 12.5" Crusader/VLTOR VIS Upper

5213

OG 18T Mount also [BD]

UWone77
15 April 2018, 14:09
OG 18T Mount also [BD]

Still have an 18T M4-1000!

fledge
15 April 2018, 20:40
Just talked to Jeff at CMT.

Full Top rail 11.5" HDX handguards will be available on the website later this week when he has the time. No word if these will be a limited run or if they will make more in the future. If you want one, I'd suggest you get one.

I check for this often. Do give a shout when you see them up.

UWone77
17 April 2018, 19:51
I check for this often. Do give a shout when you see them up.

I'll ask about it again.

Forgot I had this. 12.5" Faxon on a SMOS Non-GFY Upper.

5226

Former11B
17 April 2018, 20:09
Still have an 18T M4-1000!

With the round poofy butthole endcap? Lol

fledge
17 April 2018, 21:36
I'll ask about it again.

Forgot I had this. 12.5" Faxon on a SMOS Non-GFY Upper.

5226

Love the SM15. A short-lived classic that never made prime time (though you see the influence in the VSeven rails).

UWone77
18 April 2018, 21:33
Love the SM15. A short-lived classic that never made prime time (though you see the influence in the VSeven rails).

I should just sell it. Don't have a lower for it.

Here's another 12.5" It's a mid-length Rock Creek 12.5" Rainier did.

5227

gatordev
19 April 2018, 18:03
Is that a NiB tear drop? I have no need for a NiB tear drop FA, but it sure does look sharp. If it's not NiB, then it just looks sharp because it's a tear drop FA.

UWone77
20 April 2018, 08:54
Is that a NiB tear drop? I have no need for a NiB tear drop FA, but it sure does look sharp. If it's not NiB, then it just looks sharp because it's a tear drop FA.

No, it's not NiB. Just anodized.

EO3
20 April 2018, 12:35
I should just sell it. Don't have a lower for it.

How much would you want for it?

gatordev
20 April 2018, 13:13
No, it's not NiB. Just anodized.

Still, I'm very pro-tear drop.

UWone77
20 April 2018, 15:36
How much would you want for it?

Not sure. Might just part it out, as I'm sure someone like you would be more interested in the upper and rail only.


Still, I'm very pro-tear drop.

I like the tear drop. This one is from Iron Viper Industries. Not sure why they went away from the tear drop, seems much more effective.