Help with SBR build

General Firearms NFA
1

So I’m pricing out an SBR build with a 10.5" barrel. Dealer is suggesting a few things that have me confused.

I mentioned a muzzle brake, and he suggested a flash suppressor such as the Smith Vortex to prevent night-blindness from enhanced muzzle flash. Thoughts/suggestions?

Also, I want to use Troy Alpha rails, but they’re not available from this dealer, so I’m going to go with their cheapest quad rail and then swap it out. Which size Alpha would I go with, with the 10.5: barrel? Also, how will it interact with the front sight? The dealer is suggesting RRA gas block sight assy because he doesn’t want to mount sights on the handguard (defeats the purpose of a free float he says). I’m not sure that would work with the Troy rails. Alternatively, he is suggesting some ARMS sights. Thoughts?

2

As far as muzzle brakes go, I really like the Griffin Armament M4SDII flash/comp. I haven’t done any night shooting with it so I can’t comment on that, but I haven’t noticed any increase in flash than a standard A2, and it keeps me on target pretty well.

I’m not sure I understand what he means by saying that mounting sights on the handguard defeats the purpose of a free float. Troy makes fantastic back up sights, both folding or fixed.

3

Get what you want and bring it to him… but just off of his suggestions alone - I’m not sure I would have that much faith in his ability.

Purchase a rail - I would suggest a 9" for a 10.5" and just have him install it if you’re unfamiliar with how to install rails.

If you get a gas block w/ a sight on it - you’re limited to what rails you can put on. (I’m assuming thats what he’s referring to when you tries to stray you away from a flip up on the rail) There’s absolutely nothing wrong with mounting a front sight on the rail itself. The concept free float refers to the barrel “floating freely” from the upper with out any attachments on the barrel, like the handguard, front sight post, etc. (If you’re not familiar with the term - read this-- http://en.wikipedia.org/wiki/Free-floating_barrel)

As for sights - there are a lot of options out there. It all depends on your budget and your desires. Prices range from magpul back ups to KAC micros $40-$200 per pop. There’s fixed and there’s flip. I’m personally not a fan of Arms… I think they are a little too bulky and I’ve had issues with them when mounting different optics.

Also there are a lot of people on this board that are certified armorers and gun smiths. I’m sure if you weren’t too keen on having this guy do your work, you could send it off to someone on this board.

It’s your rifle… build it how you want.

4

Thanks. You confirmed my suspicion that gas block sight will limit my options, so I’ll go with flip ups.

As far as the rail, I wasn’t sure if I should go with a 9" and have it end short of the barrel, or do something like an 11", where just the tip of the brake/flash hider will protrude. But then I guess you wouldn’t be able to access the threads easily if needed. And I’m still not sure if I’m better off with a brake or a flash hider.

5

Youre the one shooting it…not him.

He has no business telling you how to run your setup. I run an Alpha with Troy folder and its fine. No “Purpose defeated”. It hits at 200 no problem.

I can understand opinions and advice…but his is kinda ridiculous.

A brake on that length is gonna have flash. It never bothered me and its not enough behind the gun to ruin my night vision.

Trial and error is a good way to figure out how you want YUOUR setup.

If parts dont work or you dont like it…take it off an sell it. Just make sure you buy quality the FIRST time.

6

Yeah the part of the sight made no sense. Maybe I misunderstood him. And as far as the flash hider issue - ultimately I’ll do what I like, he’s just offering advice. My only experience is with 16" barrels so I’m just not sure what to expect.

7

The flash hider recommendation is solid.

Blast from 10.5" 5.56 barrels is tremendous, even with a flash hider.

A brake will increase that.

As for the rest of the suggestions, I think your dealer is trying to sell you what he has in stock.

I would just buy (or build) an 11.5" upper from one of the good brands and be done.

11.5" CAR gas barrels tend to be less picky about different ammo and have a little less blast than 10.5", but the most important thing is to get a good barrel from a good mfg with a properly sized gas port.

8

What rail, sights, furniture, ect. is shooter preference and should be totally your choice. Just do your research and find what’s right for you…may take some trial and error.

My piece of advice to you is that if you’re going under 11.5" for barrel length (and really under 12.5" for that matter, IMO), then absolutely don’t skimp on the quality of the manufacturer…in other words, don’t buy a cheap 10.5" barrel because you will most likely have issues with them as opposed to going with Noveske, BCM, LMT, Colt, DD, ect.

Pretty much anything pertaining to SBRs have all been hashed out here, so do a search (orange search button) and really read up on what’s out there.

9

An A1 or A2 flash hider will serve you well.

10

Do you have any plans to run this gun suppressed? That could make a huge difference in your choice of both muzzle device and rail length.

11

I like to think that it’s a possibility at some point in the future, but it won’t be anytime soon.

12

If you aren’t looking for a short-as-possible, suppressed package, I would recommend 12.5". I would buy a quality, complete barrel assembly as recommended above.

I don’t think the low profile gas block vs FSB is a big deal. Obviously the LPGB will allow a longer rail. My 10.3" and 12.5" are both LPGB guns, but I actually wouldn’t mind having a FSB and a Centurion FSP cutout rail. If you stick with the 10.5" I would go with a 9" rail.

You can always change out the muzzle device. I would just start out with an A2.