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proof barrel help

kylongshot

Sergeant
Full Member
Minuteman
Feb 24, 2006
457
11
owensboro,kentucky
anyone ever seen a proof barrel with a .815 gas block that is held on by a threaded nut? I bought a barrel from Stocky's stocks and it came with a gas block and tube. The block is huge and wont fit under my handguard. I would like to change all that but i cannot find any info. The gas tube is only 13" also. I will call proof Monday but was wondering if anyone had any insight
 
Hope this helps. Anything else I can take
 

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its a proof ar15 barrel
 

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That’s wild. They don’t show anything like that in their diagrams. Only other barrel I know of with threads before the gas block is an SR15.
 
Never seen anything like it. I saw part of the part number. What’s the whole thing?
 
I'm guessing this is the barrel kit they advertise that comes with a brake, adjustable gas block, and gas tube?


This part caught my attention on the page:

"These are a special run that Proof offered that come complete with muzzle brake, adjustable gas block and gas tube. You must use everything included in the kit since they use proprietary parts."
 
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Actually looks like a good setup, foolproof indexing and positioning of the gas block.
 
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I'm guessing this is the barrel kit they advertise that comes with a brake, adjustable gas block, and gas tube?


This part caught my attention on the page:

"These are a special run that Proof offered that come complete with muzzle brake, adjustable gas block and gas tube. You must use everything included in the kit since they use proprietary parts."
well fuck! i missed that line......
 
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I would see about getting the handguard modified to run with it assuming you could finagle it over at all. Then again I’m sure none of this is what you were hoping to accomplish.
 
That's the direction I'd go too. Stocky's had a pretty shitty product page for this one, if they'd led off with the part about proprietary parts being used and not used stock photos, it would've avoided a bunch of confusion. Good luck.
 
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absolutely hear ya there. Should have known better from the get go
I've got one right now too, I'm sure many of us do. It's in our nature it seems.... hopefully it can be returned, though it is a cool set up, but not worth it unless it can't be returned.
 
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....it appears to be a replacement barrel for a Knights Armament platform. KAC uses that key slot & threading for gas block indexing and retention. If the issue is handguard fitment, I imagine a KAC handguard will work with it.
 
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does anyone know if these are definitely KAC setups, Ive got a old AAC 16 inch upper I was thinking of putting a new barrel in and this would be perfect if it will fit.
 
That is actually a really nice barrel, and even though it is a bastard you can still build a very nice custom AR around. I recently help a friend build one for 3 gun with it. Even though it has an oversized block we were able to use a 10" BCM Alpha KMR handguard with it and a stripped BCM upper. The installation was a little different from normal in that we had to install the handguard before installing the block and tube. However, the gas block is made to be inserted into those slots on the barrel, so the gas tube perfectly aligns with the gas port when you slide the block in place. I also liked the way the slot and nut system working for securing the block in place. When the nut is tightened to spec it holds the gas block as securely as pinning it would, and it is much easier to remove.
 
This actually seems like a pretty good deal in terms of crap you get with it
 
Ahhh, interesting! I just ordered this kit, same reason, price caught my eye; willing to put up with some annoyance for 540 shipped.

Now just a matter of figuring out how to get a handguard to fit… savage one, based on pic rail copy, paste, and count, is roughly 12.4 on the underside, cut back to 10.2 (ish) to clear the block… wonder if smoke composites could do a rifle diameter version of the cut-back brekke customs pcc handguard… or not, maybe. Seems like it would eat up anything I saved going with the kit in the first place…

Other option might be to see about trying to find the adjustable block off of the savage Valkyrie long range upper… that one looks like it had the same mechanicals/attachement, but in a smaller package to fit inside the rail…
 
That is actually a really nice barrel, and even though it is a bastard you can still build a very nice custom AR around. I recently help a friend build one for 3 gun with it. Even though it has an oversized block we were able to use a 10" BCM Alpha KMR handguard with it and a stripped BCM upper. The installation was a little different from normal in that we had to install the handguard before installing the block and tube. However, the gas block is made to be inserted into those slots on the barrel, so the gas tube perfectly aligns with the gas port when you slide the block in place. I also liked the way the slot and nut system working for securing the block in place. When the nut is tightened to spec it holds the gas block as securely as pinning it would, and it is much easier to remove.

Do you happen to know the torque spec for the gas block nut? I don’t recall seeing it in the MSR 15 manual…
 
Ahhh, interesting! I just ordered this kit, same reason, price caught my eye; willing to put up with some annoyance for 540 shipped.

Now just a matter of figuring out how to get a handguard to fit… savage one, based on pic rail copy, paste, and count, is roughly 12.4 on the underside, cut back to 10.2 (ish) to clear the block… wonder if smoke composites could do a rifle diameter version of the cut-back brekke customs pcc handguard… or not, maybe. Seems like it would eat up anything I saved going with the kit in the first place…

Other option might be to see about trying to find the adjustable block off of the savage Valkyrie long range upper… that one looks like it had the same mechanicals/attachement, but in a smaller package to fit inside the rail…
Strike industries gridlock should leave plenty of room for that setup
32273978-63B8-4DB7-88B7-2794CE2A855F.jpeg
 
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Do you happen to know the torque spec for the gas block nut? I don’t recall seeing it in the MSR 15 manual…
I was able to get the torque spec by calling 1 (406) 756-9290 Unfortunately, I didn't record it at the time, so you will probably have to give them a call. Good luck with your build!
 
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onthex — Oh, awesome thank you! I will give them a call!

rooster — These are pretty neat, and definitely would fit, but they are a bit heavy… ended up going with a KMR Alpha 10 for the time being; depending on how that works out I’ll either stay with it, or get something longer and have it cut out like for an FSB.
 
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To follow up a while later…. called proof, they gave me install info and sent me a pdf of same. Attaching the PDF in case anybody else needs it.


Added note on the install… getting the gas block nut to spec is a pain, since there’s very little barrel available to clamp to. I ended up using the pic rail side of pin-style upper vise block… bridged the section of rail on the top of the gas block with part of the handguard, and relied on the combination of the gas block alignment slot and the stiffness of the rail (plus the fact the rail has an alignment bridge to the upper) to deal with the torque. It seemed to work acceptably, and nothing broke… but use at one’s own risk of course.


Went with a BCM KMR Alpha 10.5 for handguard, kind of a different look with the exposed block assembly, but I’m happy with it. Only downsides are that the thin rail makes the optics look kinda chunky… and that I probably need to get a hand stop or foregrip as an ‘end of handguard’ warning.

187FB0C9-A532-4D78-A805-E11B504C68E6.jpeg


Also looks kind of funny without a mag in it… kind of a visual balance issue.

Anyhoo. Thanks for the info, hope the pdf is useful to someone!
 

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I think, but am not entirely sure, I checked to see if that was a thing… but either it was really expensive, I couldn’t find the mod 2 gas block specs, or I found them and it wasn’t going to fit… looking again just now…. I can’t find inner diameter or length specs… however, if you’ve got more info (or more patience, I suppose), might be worth rechecking.

Meanwhile… Savage made a couple of other MSR series rifles that used proof barrels and what looked like the same mounting system. Those rifles had a low(er) profile adjustable gas block that looked like it might fit under a normal handguard. Problem with that was that Savage doesn’t appear to sell them individually. The one or two parts suppliers listed only a handful of MSR series parts, no gas blocks among them. I don’t have an actual MSR to get the serial number from to do a parts lookup through Savage dealer stuff… no luck finding one on GB or other forums either… but, assuming you could get fitment info and get a replacement part, that would likely work well.


Actually, looking at the front of this upper, that looks like a not-carbon-fiber maybe-or-maybe-not-proof barrel with an adjustable gas block and castle nut for same.

Some minutes of digging later… it looks like the MSR 15 over watch recon 2 sales flyers mention a “savage gas block nut with straight gas tube.” And a search for same… okay. Seems like the whole MSR 15 series, or at least more recent models, use the same system. It’s not a KAC gas block, but anything that fits under a normal rail might be handy if you can find one.