CLOSED 65G MONSTER 12.7 Barrel Buy

[454bore]

Smaller port size is good for suppressor.
You can always open but can't reduce.
I like the port to be small.

[Kswhitetails]

I thought that was what an adjustable gas block was for? Or an adjustable carrier? Or buffer alternates? Ha. There goes my brain again, off on a tangent...

[ClutchAutomatic]

flat out bought everything needed for next build, barrel's came come soon enough haha.

[BluntForceTrauma]

O.O We changed the port size? Reasoning here?

Bill Alexander says 6.5 Grendel gas port sizes are roughly the same as 5.56 ports for same length barrel. Yes, 556 is higher pressure, but 65G has greater powder capacity. He says it comes out a wash.

Mil-spec gas port for 556 Mk18 10.3 barrel is 0.070. We use 0.073 on our 12s, which is right on the edge of being more than enough gas — all things considered it's better to be over- rather than under-gassed, true, but to strike that balance between reliable function and smooth shooting is even better — and so with these 12.7s, which add just that much more barrel length (and is 2 inches over Mk18, to boot), we go over the tipping point and use a port the next size down.

Finally, as 454B mentioned, there's a good chance of suppressor use on these, which also argues for a smaller port.

Could go the easy route, and just over-gas the hell out of it to be on the safe side, but am really trying to create a superlative product and do it just right. Goldilocks would be proud.

[Teefers]

Funds and form sent for 1 barrel and 1 bolt! Thanks!

[Teefers]

Is the general consensus that any 12" handguard will allow enough clearance for a muzzle device and a suppressor with these 12.7" barrels?

Planning on using a rugged suppressors micro 30 on mine and because of the mount design i do not want access to the locking collar blocked by the handguard.

Looking at a getting another 12" lightweight mlok handguard from Midwest industries.

[ClutchAutomatic]

Is the general consensus that any 12" handguard will allow enough clearance for a muzzle device and a suppressor with these 12.7" barrels?

Planning on using a rugged suppressors micro 30 on mine and because of the mount design i do not want access to the locking collar blocked by the handguard.

Looking at a getting another 12" lightweight mlok handguard from Midwest industries.

12" handguards can vary in length for example seekins does 12.5 MI does 12-5/8 and SLR does 12-3/16. I am attaching a flash hider to the end and it should give me more than enough clearance for my can. Also have a handguard made for a suppressor though. I think the rule is to have about an inch difference between handguard and barrel actuals.

[BluntForceTrauma]

From the receiver face to the muzzle thread shoulder, these barrels measure just a hair more than 12". They are absolutely as short as possible while still allowing use of true 12" handguards.

So, one needs to verify from the manufacturer the dimension of their handguard — measured from the face of the receiver to the very end of the handguard. Any handguard 12" or less on these barrels will not cover or shroud a muzzle device with its crush washer. Any handguard 12" or more, using that method of measurement, will shroud a corresponding amount of muzzle device.

If the MI 12" MLok is actually 12-5/8, then it will shroud the muzzle device by 5/8, etc.

[Teefers]

Thanks for the detailed explanation Blunt Force, I figured it wouldn't be as simple as just finding a 12" rail I like. I'll probably try to go for an 11-11.5" handguard to be safe. I'm finding out those don't seem to be nearly as common. Lots of companies seem to jump from 10" to 13" or so.

I do have a 12" ALG emr that I like so I may have to bust out the tape measure and see how it measures up. Also planning on looking at the BCM and geiselle offerings. Pretty excited to get this rifle built.

[Kswhitetails]

Larue makes an 11". Should be just about perfect with the 12.7. My 12" barrel was shrouded by about 1/8 inch.

[ClutchAutomatic]

Larue makes an 11". Should be just about perfect with the 12.7. My 12" barrel was shrouded by about 1/8 inch.

How long was your handguard?

[Teefers]

Larue makes an 11". Should be just about perfect with the 12.7. My 12" barrel was shrouded by about 1/8 inch.

I went and looked, but it seems like they are all quad rails except for the stealth 2.0 which I think requires use of their proprietary upper receiver...

[Kswhitetails]

The quad rail is what I was referring to. The rail itself from the rear of the nut to the end of the rail is 11.125" without the barrel nut or extension flange installed. The extension flange should add somewhere around another eighth, so total length installed should be within a few fractions of 11.25 or so inches. When I get the barrel in and install, I will post more pics in my build thread. From what I can assume so far, there should be about .4 inches of barrel extending beyond the end of the rail, followed by the threads. The Larue Tranquillo brake indexes behind the threads a bit so I needed the extra length to be able to mount my suppressor. Here's a pic:

by bosephus, on Flickr

[dpete]

BFT Are we still looking at the end of March for these barrels? Just calculating out 8-10 weeks from your original post.

[Clausewitz]

I'm in. Paid and emailed form