Rifle length gas system on 16" barrel

[Mach1Run]

My new build. FN hammer forged 16" middy gas.
With an A2 standard rifle buttstock. I like this stock on this gun the most I think.

I am building one like this saving for the barrel and have to decide on sights / muzzle device. I have one of those ALG triggers I am going to try in it.

[KBScobravert]

My new build. FN hammer forged 16" middy gas.
With an A2 standard rifle buttstock. I like this stock on this gun the most I think.




I never would have believed that the A2 is the shortest of the stocks after the adjustables are fully extended. The PRS on top is not out all the way either. Bottom rifle is Threefingerpete's upper.

[ThreeFingerPete]

True dissipators don't run because their is very little dwell time, which requires a larger volume of gas due to the shorter gas cycle. Thus, if something doesn't work, it's a very hard to tune system. Similar to a 10.5" carbine gas AR system. The 11.5" is MUCH smoother due to increased dwell time and a smaller gas port.

[KBScobravert]

Chris, here is a carbine barrel up top compared to a middy barrel. Both are 16".



They say the middy is the best and that true dissapators don't run.

[KBScobravert]

CJ, you were right. .750" opening on the standard FSB and .730"ish on the front of the barrel mine will sit.

What do you think of this one and having it drilled to .730" then pinned?

http://www.midwayusa.com/product/410205/doublestar-a2-front-sight-gas-block-with-bayonet-lug-ar-15-lr-308-625-inside-diameter-steel-matte

edit: read the comments and it looks like someone did just that (reamed it open) but used set screws to lock it down instead of pinning it. I guess I could get the base drilled and barrel dimpled at the same time to use a set screw also.

[CJ]

Well I am impressed so far with Steve at MGS. Very nice guy, didn't try to talk "down" to me like some gun people try to do when I call in.

The line I loved the most is "I will try to do this the cheapest for you, while keeping it reliable"...perfection!

He said $40 for the labor and $20 - $25 for the FSB. He is going to try and salvage my current A2 FSB and handguard cap, but I told him they were pretty mangled.

Dropping it off Saturday, will let you guys know how it goes.

Now...where do I find (locally) MOE rifle length handguards?

Edit: CTD has them for $40...looks promising.

Yeah Steve is a great guy, down to earth and he knows what he's doing.

[futant]

i had a bushy dissapator for a while.
never thought it was that big of a deal to have the longer sight radius when i shot it
just annoyed the shit out of me knowing i had more weight up front that could be lost.]
sold it.

[KBScobravert]

Well I am impressed so far with Steve at MGS. Very nice guy, didn't try to talk "down" to me like some gun people try to do when I call in.

The line I loved the most is "I will try to do this the cheapest for you, while keeping it reliable"...perfection!

He said $40 for the labor and $20 - $25 for the FSB. He is going to try and salvage my current A2 FSB and handguard cap, but I told him they were pretty mangled.

Dropping it off Saturday, will let you guys know how it goes.

Now...where do I find (locally) MOE rifle length handguards?

CTD catalog counter. I bought the last set the store had last week for my identical build.

[IHaveAMustang]

Or hit up Steve at MGS and get a quote from him, I think he might be a little better on pricing.

Well I am impressed so far with Steve at MGS. Very nice guy, didn't try to talk "down" to me like some gun people try to do when I call in.

The line I loved the most is "I will try to do this the cheapest for you, while keeping it reliable"...perfection!

He said $40 for the labor and $20 - $25 for the FSB. He is going to try and salvage my current A2 FSB and handguard cap, but I told him they were pretty mangled.

Dropping it off Saturday, will let you guys know how it goes.

Now...where do I find (locally) MOE rifle length handguards?

Edit: CTD has them for $40...looks promising.

[KBScobravert]

Well the problem you're going to possibly have is the gas block location's diameter is larger than the barrel (hence your ability to slide it over the barrel and onto the tighter fitting gas block location). You would have to add material to either the barrel or the FSB. That is assuming it's a fixed diameter on the FSB. A pinned FSB *might* work, but my guess is it would be far too loose. Do they use a special FSB with a smaller diameter to clamp the .730" portion of the barrel or something?

Very true. Might have to go with a FSB that is split on the bottom and uses side force to clamp to the barrel. Eitherway I find out tonight when I get home.

[CJ]

Not sure yet. I am waiting for both the barrel and the FSB to show up today from the Brown Santa.

If he makes it by 1p and it fits fine, I am gonna swing it to MSG before I go in to work and pick it up tomorrow to assemble it.

Worse case, I ask Brooks to chuck it in his lathe and make a pass or two.

Well the problem you're going to possibly have is the gas block location's diameter is larger than the barrel (hence your ability to slide it over the barrel and onto the tighter fitting gas block location). You would have to add material to either the barrel or the FSB. That is assuming it's a fixed diameter on the FSB. A pinned FSB *might* work, but my guess is it would be far too loose. Do they use a special FSB with a smaller diameter to clamp the .730" portion of the barrel or something?

[IHaveAMustang]

Fsb $30
Labor $50

After reading Keith's post, I assume MGS couldn't re-use my handguard cap? They would have to cut it off and put a new one on behind the FSB at the end of the rifle.

I'm going to give MGS a call on lunch, I prefer to support local anyways...and it seems to be cheaper.

[KBScobravert]

how is the fitment of your FSB without it being on a machined shaft?

Not sure yet. I am waiting for both the barrel and the FSB to show up today from the Brown Santa.

If he makes it by 1p and it fits fine, I am gonna swing it to MSG before I go in to work and pick it up tomorrow to assemble it.

Worse case, I ask Brooks to chuck it in his lathe and make a pass or two.

[CJ]

I will be up there tomorrow for my pin holes to be drilled.

I'm heading down tonight to pick up a colt gold cup 1911 .22 plinker.

[CJ]

I am building a dissapator this week on a FN 16" barrel with a middy gas system and a standard FSB in the rifle position. The FSB will only serve as the forward sight and to hold my frt handguard cap.

If one wanted to be cheap and already had a carbine barrel you can "close" a gas port and drill another in either mid or rifle location. However I hear 16" doesn't like a gas port so close to the muzzle.

Sent from my SAMSUNG-SGH-I727 using Tapatalk 2

how is the fitment of your FSB without it being on a machined shaft?