AR15 build questions

Hello. I recently acquired a few AR-15 parts and I'm looking to assemble the rifle but I'm a bit stuck in-between lines. Any advice would be appreciated!

Parts list
Handguard: Hogue extended length forend in ghillie green (Measures exactly 15" in length but 14.5" beyond the upper receiver barrel nut threads)
Barrel: Heavy contour 14.7" .223 Wylde 1/2-28 chrome lined barrel mid-length gas system .750 gas block diameter
Stock: Mission First Tactical Utility stock with cheek riser
Mil-Spec buffer tube
Spikes no provision upper receiver + mil-spec lower receiver
Charging Handle: Radian Raptor AR-15 charging handle
Gas block: Wojtek adjustable gas block .750
Mid-Length gas tube
H2 buffer
Standard buffer spring
(No dustcover or forward assist due to the no provisions upper receiver)
Pretty much all Strike Industries lower parts with a standard mil-spec trigger kit
Rainier precision match grade BCG

Out of the list, I currently own the BCG, barrel, lower receiver (no upper yet), handguard, and stock.
My main concern is the whole barrel+handguard+muzzle-device scenario. According to a series of web forums, a 14.7 barrel is about 13.5 inches once you deduct the barrel extension that rests within the upper receiver and compare the length of the barrel to the length of the handguard. The handguard by itself is 15 inches in length but once threaded onto the upper receiver, it comes out to exactly 14.5 inches. So by calculations, would the handguard be 1 inch longer than my barrel? I'm trying to go for the recessed-muzzledevice look. The muzzle device I'm currently on the edge of purchasing is a War-Sport GP-S comp. It measures out to exactly 2" and it's already pre-drilled for the whole pin and weld deal. Would the combined length of my parts conflict with each other and result in a blown up handguard as I've read on forums, or would this be perfectly fine and I'm worrying for no reason at all?...

I stumbled across a solution but I'm too uneducated on this topic to know if it's a solid solution or not. From many companies, you can purchase barrel thread extension adapters that add anywhere from 0.2 to 2 inches of length to your barrel. The diameter and thread is the exact same, measuring out at 1/2-28 TPI - 1/2-28 TPI. Does this solution affect accuracy in any way or would it be the way to go?

Hoping to hear back from experienced builders or at least anybody with knowledge greater than me. Thanks!

I have a 9.7" slr rail on a 10.5" barrel. I probably could have gotten away with a true 10 and still been able to get a flush look with the capability of being to quick disconnect my can. Just wanted to play it safe though. See pics.








Also here us a good educational vid on the subject matter from slr.

You will have 1.5-1.7 inches of muzzel device sticking out from the handguard. I’d stay away from the barrel thread extension. That sounds like a fix for something that ain’t broke.

The biggest problem with a pinned/welded flash hider is what do you do if something breaks? I have a shooting buddy that has a 14.5" AR with a welded FH, whatever company built his upper welded the FH all they way around! His adjustable gas block broke, the adjustment thingy fell out, no sweat the manufacturer sent him a replacement. But how do you change it? Unless it's a two piece clamp-on type, you've got troubles. My advice is just go with a 16" tube and eliminate the problem.

BTW, the barrel length is measured from the face of the closed bolt. The barrel extension is not counted.

dougstump said:

The biggest problem with a pinned/welded flash hider is what do you do if something breaks? I have a shooting buddy that has a 14.5" AR with a welded FH, whatever company built his upper welded the FH all they way around! His adjustable gas block broke, the adjustment thingy fell out, no sweat the manufacturer sent him a replacement. But how do you change it? Unless it's a two piece clamp-on type, you've got troubles. My advice is just go with a 16" tube and eliminate the problem.

BTW, the barrel length is measured from the face of the closed bolt. The barrel extension is not counted.

Click to expand...

He already owns the barrel so, depending on his budget, a 16" barrel may not be an option. But I will piggyback on your post with my experience. I put together a 14.5" AR10 with a pinned and welded muzzle device because I wanted as short as possible and still have a stock. I paid to have the barrel shaved down to properly time the muzzle break. The rifle will be a host for a can so a crush washer wasn't an option and I didn't want to use shims. I gave the gunsmith the barrel with the gas block already installed and he did his thing. I went to pick it up and realized I forgot to put the barrel nut on there. Well f@#$. So we cut the gas block off and I found a 2 piece from YHM. The rifle was having some cycling issues so I decided to get an adjustable. I could find 3 two piece adjustable gas blocks, JP Enterprises, Witt Machine, and some other one I can't recall right now. All that extra money, work, and hassle to save 1.5 inches. I won't do that again.

To the OP, it looks like you already have the parts that would be the variables, the barrel and the handguard. If you know someone who builds rifles or are friends with a gunsmith, you could "borrow" an upper and see where everything lines up. Or the Spikes upper may be the next purchase. Or if you already have an AR, you could take it apart and test everything with that upper. I'll look and see if I have a spare upper laying around but I think all of my builds in progress already have the barrels attached.

I suggested the two piece gas blocks to my associate, he doesn't want to hear it. When I said it was going to take some very slowly and careful milling to remove the busted gas block he really screwed up. He looked at me across the table and said, "Well, you're not a gunsmith!" So he's going to be spending a lot of money getting it done instead of buying me lunch. Cause I ain't gonna do it.

Yep...it took a milling machine and quite a few shallow passes to make sure it didn't mill into the barrel. Then a few passes on the opposite side to create a weak point so the newly milled hole could be opened up to get the thing off. So I get the appeal of a 14.5" barrel because I had it. And I have another 14.5" build in the works. But I'll probably just use a non-dead air muzzle device and rocksett it. I think that would be the way to go if I don't plan to use the rifle as a can host.

No amount of math will get you the answer you seek!!!

I am joking, but it does get hard to figure this stuff out beyond just trial and error.

Your barrel and muzzle device will most certainly be longer than the 15" hogue handguard.

I am pretty sure a 17" handguard is the needed item to cover most 16+ inch barrel/muzzle device setups, but will vary depending on the length and style of the muzzle device.

Another thing to note is that you should not cover up some muzzle devices as they vent gas sideways... Might not be an issue but I always leave a side venting device uncovered just to be sure. Something like a flash can, linear comp, or flaming pig can be covered as those just vent out the front.

This also brings up the important note that pinned and welded barrel guns might be better off using an adjustable gas key or bolt carrier instead of an adjustable gas block. Or the 2 piece block as noted above. I stick to solid steel low profile blocks on the pinned and welded barrels. I also do not weld the muzzle device on anywhere but at the pin, making it possible to be removed without trashing the barrel.