Rifle fore-end on 16" middy

[memilanuk]

Hey there,

Right now I have a RRA 16" middy barrel with a mid-length fore-end, YHM flip-up front sight/gas block, etc. I've been getting an itch to change something, and thought I'd address two of the issues I have with the current setup - namely, when running suppressed I've broken a cotter pin or two in the BCG and I've managed to reach out and grab onto that front-sight/gas block once too many during a string of fire... ouch! So I was thinking about putting a rifle length tube like a Midwest Industries SSK-Keymod 15" tube or a Seekins MCSR V2 keymod rail, plus a low-profile adjustable gas block. I'm hoping the MI fore-end tube will transition to my Gemtech Trek 5.56 suppressor or a brake without looking too odd. I don't expect to want to adjust the gas block a whole lot, but I do worry about being able to reach it inside the fore-end tube. Optionally, looking into heavy buffers, CWS, that sort of thing.

Sorry if these are silly questions; I've been away from the AR scene for years and never really was that up to speed on the HS/LD stuff in the first place. Just trying to avoid making too many expensive mistakes here.

Thanks,

Monte

 

[nhm16]

I really like the MI SS gen 2 hand guards. Have a 15" Ss on an 18" barreled upper, and just ordered a 10.5" SSK for a 12.5" SBR I'm building. THe SSK is especially nice because it comes with QD sockets, saving you having to buy an add on, and a single piece of rail, which you can use to attach an Atlas or mount a flashlight. In fact I like it more than the Noveske NSR. Just helped a friend install an NSR on his SBR and I didn't like how the tube attached via 6 screws, or how everything is an optional add on.

As for the gas block, I recommend the Syrac or SLR, which have detents in the adjustment screw and thus won't back out on you.

 

[memilanuk]

Cool, the more I've been looking at the MI handguard the more I'm jonesin' for one

Is the adjustable gas block necessary with a heavy buffer and/or spring? Will the combination of the two be too much of a good thing?

 

[Nisils14]

Adj gas block is a must with suppressor IMO. Easier on the gun, especially the wear and tear parts. Getting to the gas block with 15" HG could be a pain with a mid gas system, especially if you're keep that suppressor on full time. 11-13" HG would be much easier to reach an adj. gas block.

 

[LRRPF52]

Hey Monte!

I had a RRA 16" MLGS that I shot a lot suppressed with a QD can in extreme cold weather conditions. I put a JP 12" rifle length handguard on it with a FSB pocket cut, but I would use a low-profile gas block if I were doing it again today.





I didn't have any issues with the BCG in extreme cold, so in those conditions, I think the gas system was being gassed ideally (-27C to -30 C, or -17 F to -22 F). I didn't have an adjustable block, as you can see.

I would first approach this with weights on the carrier and buffer end, then look at an increased power recoil spring, before messing with an adjustable gas block. Do you have an M16 carrier, or neutered carrier? If you have a standard telescoping stock assembly, you probably have a 2.9 oz buffer. I found the MGI RRB buffer to be smoother than a 20" RLGS AR in my RRA 16" MLGS, and it was very pleasant to shoot.

Pull your FSB off and see what gas port diameter you have. That is going to be one of the biggest factors in the whole equation.

If you are damaging firing pin retaining pins, that is an indicator of some pretty extreme rearward thrust of the firing pin, and I have had it happen on my .260 Rem AR10 when doing pressure ladders with N540 and 130gr VLD's in the summer at over 100 F.

What loads have you been feeding it suppressed?

Paul

 

[memilanuk]

The ammo used has been primarily BVAC 55gn FMJ (commercial ammo using 1x mil brass). No idea what kind of powder, etc. I'll have to pull the FSB off tomorrow when I get home. I'm not familiar with the term 'neutered' carrier... I've heard of neutering the ejector spring...?

Here's a pic of what the package looks like now:

 

[tickled pink]

milanuk next time you take pictures try to keep the sun in back of you. Then you will see the details of your weapon. Just trying to help.

 

[MSTN]

I've installed several of the Seekins forends. While the design is sound, the execution I've seen has been less than 100%. Problem: The screws used to install the forend to the barrel nut. They're apparently made from longer screws that have been chopped to the correct length - with emphasis on the word "chopped". The threads on the screws needed quite a bit of dressing up. The soft aluminum of the barrel nut does not take well to screws with threads like this.

I've not used the MI.

The simplest forend in the marketplace to install correctly is the Geissele:

Geissele Mk 4 shown above.

There is no barrel nut "timing" involved. You simply install the barrel nut to the proper torque using the special tool included with the forend. If you don't have a torque wrench, you can probably take a guess and be fine. The handguard is simple to line up properly with the upper receiver, and there's a clever yet simple anti-rotation feature built into the forend.

Another reason I like the Geissele Mk 4 is it has enough internal volume to keep your support hand just a tad further from the barrel. When shooting suppressed, the suppressor traps an incredible amount of heat, which of course is transferred via conduction to the barrel. Then, convection and radiation conspire to heat up your flesh where you hold onto the forend.

 

[memilanuk]

Are those ~15 tubes on 16" barrels?