Some A2-style Front Sight Questions

[Louca]

I am thinking of building an AR with a standard (20") barrel and A2-style front sight. But instead of the usual A2 hand guard, I would like a free float hand guard that still looks like the original A2 one. This barrel, sight, and hand guard will all be separate parts (not pre-built). The barrel I am thinking of getting is from Brownells (080-001-017WB) as is the free float sleeve/hand guard (739-000-003WB). This is my first build, and I do have a friend that can help me and has most of the tools available.

But exactly what front sight to get is my question. Here are my questions regarding using a standard, un-drilled, pinned-style sight: How hard is it to be sure the sight is properly aligned? How can you know when the sight's gas hole is aligned with the hole in the barrel? I mean, once you drill holes, you're done with any fore/aft left/right alignment, I would think. How hard is it to drill the holes for the pins (especially into a stainless barrel)?

I guess an alternative to drilling and worrying about exact alignment is to use a clamped front sight kit from Armalite (EU0240MPKIT). One negative there is they are on continuous backorder and will come in who-knows-when. Anyone have any cautions against using a clamped front sight? If they really are that much easier to install, why don't more builders use them?

Lou

 

[HisStigness]

Somebody will come along and correct me if I'm wrong, but I'm pretty sure that pinned gas blocks use tapered holes, i.e. a larger diameter at one end so the pins don't come out. Alignment and drilling the holes myself is something I wouldn't want to attempt because it's an easy way to ruin a $200 barrel. I'm sure it's possible to learn yourself, and I wouldn't be surprised if somebody makes a tool to get the drill holes aligned, it's just something I wouldn't want to do.

Somebody might also make an a2 front sight that attaches via set screws that utilize the dimple on the bottom of the barrel (if yours has one).

 

[MistWolf]

Check out White Oak & Compass Lake for the solutions you're looking for. Also, a good smith can drill the FSB for pins. Pins can either be straight or tapered. Tapered hold better

 

[Lennyjoe]

The last two barrels I've purchased have not had the taper pin holes drilled in them. I used A2 site bases on both and have drilled and threaded the pin holes with a 4mm tap and used 4 small set screws and some blue thread lock with success. Only reason I did that was because I had them laying around and wanted to use them up.

I talked to a gunsmith about drilling the barrels myself and he advised against it. Recommended the set screws so I gave them a try.

As for longevity, the jury is still out on that. Haven't shot them much or beat them up in the field so I can't say for sure how they will hold up.

 

[AlexanderA]

Buy a barrel with the sight tower/gas block already installed. It's much easier to remove/replace it (in order to install the free-float handguard) than to put it on from scratch.

The taper pins remain the preferred way of fastening the sight tower.

 

[Lennyjoe]

^^^ Agree with AlexanderA ^^^.

But, since I had two laying around and the rifles are low budget builds to sit in the safe "just in case", I tried the set screw method.

For a full on, life saving, tactical rifle, you should use a more secure method.

In saying that, I think I'm just going to buy some YHM clamp on fold down front sights and be done with it.