First Time AR Build Questions

[BakaLogic]

Hi All,

I don't know why, but I got it into my head that I would try to build my first AR. While I was pretty excited at first, I'm starting to get nervous now that the parts are coming in. I had some questions that I was hoping I could get answered here.

1) I have a Spike's Upper and a Black Hole Weaponry barrel. From all the videos I've seen, the barrel just kind of slips into the upper, but that doesn't happen in my case. It's a tight fit and stops about 1/8 of an inch from being fully seated.

The internetz suggest heating the upper and freezing the barrel as well as using white lithium grease (well, moly), although I've also read someone suggesting to use 600 grit sandpaper to sand the barrel extension and upper. Finally, someone mentioned using a rubber hammer and a 2x4 (as a buffer) to hammer the barrel in.

Which way would be best?

2) I have a low profile gas block with set screws and a barrel with no dimples

http://www.joeboboutfitters.com/Black_Hole_Weaponry_16_5_56_M4_Barrel_416_SS_p/bhw-16c-m4b.htm

I've read some people say that it's unnecessary to dimple the barrel, other people say that the set screws will dimple the barrel when you screw them in and some say take it to a gunsmith. I'm leaning toward taking it to a gunsmith as I don't have the tools to do it myself. Is there any reason not to?

3) I bought a barrel with a carbine length gas system and only after purchasing read about how a mid-length would be preferred. I noticed that Spike's sells a micro gas block that's adjustable:

http://www.spikestactical.com/new/z/spikes-tactical-enhanced-adjustable-micro-gas-block-750-wset-screw-p-738.html

It's pretty expensive compared to what I purchased. Would adjusting the gas with that gas block make any noticeable difference to recoil? I'm also a bit worried that the gas block wouldn't fit underneath the 12" handguard I purchased. (Midwest Industries SS Gen 2).

http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_id=450

Apologies for the length of the post. If anyone has any insight on these questions, I'd appreciate some input!

[wash]

Slow down.

First you need to figure out why the barrel does not go all the way in.

Does the upper receiver have a burr in the bore? Is the barrel extension tapered? What actually stops the barrel?

Once you answer the questions then you can decide on how to fix it.

Don't skip to deciding how to fix it before you know what the problem is.

Adjustable gas blocks can tune for recoil but they aren't a replacement for mid-length gas. Maybe ask about an exchange?

About barrel dimpling, I would do it because it keeps your bottom thread from getting mangled and jamming the gas block on. It also keeps you gas port aligned even if the set screw loosens up a little bit.

[BakaLogic]

Thanks for the reply Wash.

I'll try and see if I can figure out what stops the barrel and post again if I see anything.

Bummer about the carbine gas tube, but I don't think Joe Bob has anything I want or will return it. I'll probably just chalk it up to first time builder's error and suck it up. It'll be my first AR so I don't have anything to compare it to anyway. :P

I'll probably hit up Wiser Owl's Gunsmith (since it's close) for the dimpling.

Thanks again for the response!

[phrogg111]

My rifle's barrel has no dimples, and it works fine. I've taken off/reinstalled my gas block twice for work on it, and I've had no issues. I've made sure the gas port is aligned properly inside the gas block, and there were no problems.

I also doubt your barrel being carbine length instead of mid length will affect much. Only one way to find out: Try it.

The barrel not fitting in... That seems odd. You've made sure that your little pin on the barrel extension is fitting in the slot in the upper, right? Mine went in with almost no force. If you're sure the pin is lined up, try a rubber hammer. Don't hit too hard on it - you'll have to get it back out if there's problems.

And definitely double check for burrs on anything.

It shouldn't be too hard to fix problems as they arise - Don't panic! You'll be fine.

[socalbowhunter]

It shouldn't be too hard to fix problems as they arise - Don't panic! You'll be fine.

Amen.

I'd be willing to bet that there is a more experienced builder right here on CGN that lives near you and would be willing to stop by and assist you. In fact, AIMSMALL, a member on here, hosts build parties in SD all the time. PM him and see if you can bring your stuff to his next bp and there will be a ton of knowledgeable people there and all the tools you could ever need.

[kcstott]

The other thing is don't worry about recoil on an AR. Only a twelve year old will have problems with recoil. They are a very mild weapon to shoot. Which makes them fun to shoot.

As for your barrel not fitting it is most likely the upper being tight. But that needs to be confirmed first.

[Intimid8tor]

KCstott has it right. Figure out the why before you work on the how. Once you know the why, we can give advice on the how.

[kcstott]

Wash mentioned that first.

[BakaLogic]

Hey guys,

Thanks for all the responses, it's very encouraging.

I bought a set of calipers from Radio Shack today and tried to measure the barrel extension to see if it's tapered. It seemed to measure a pretty uniform .98 inch (although I believe the zero was off by -.02 so it might have been a uniform 1.00 inch) so I don't think that the extension is tapered.

I looked over the upper receiver section with a LED flashlight and it looks smooth and as best I could I tried to drag some dental floss around the area to see if it would catch on a burr. I didn't find anything but now my upper is minty fresh.

I'll play with it some more, but I'm still unsure of why it's sticking though I do see a place inside the upper where the black part has worn off probably from an earlier attempt to seat the barrel fully. (At one point it was stuck pretty hard and I almost couldn't remove it by hand.)

After I posted last night, I did some more Google searching and found a thread in a forum where a couple people were having the same problem with BHW barrels and used mallets. One person said they contact BHW and they said it would be okay to use a mallet to tap it in. I've emailed their support to make sure that's okay but it still makes me a bit uneasy.

I'm more comfortable with the idea of a carbine length gas tube and since I'm the type of person who likes to err on the safe side, I'll probably still have a gunsmith dimple the barrel even though I'm now more comfortable with knowing I can do without if I need to.

Thanks again for all the comments and input. I'm glad to be part of such a helpful online community.

[BakaLogic]

AR Build Finished.

Hi all,

Not sure how often you get followups but I wanted to thank everyone again for their encouragement and sharing their wisdom and experience.

I finished my first AR build on Wednesday and took it shooting yesterday. I found out a few things:

1) Building an AR is a lot like building a computer: You have to take a step back when you're feeling frustrated or angry otherwise you take a chance on breaking something. In my case I whacked the gas block roll pin way out of shape, but luckily I had a another gas block that I wasn't planning on using that seemed to fit fine.

2) Building an AR is not at all like building a computer: I never had pieces of a computer go shooting across the room while I was building it. The same can't be said for the detent pin I lost. Luckily the Spike's LPK I had came with two.

(Thanks to the person in another thread who suggested using a large plastic bag to catch pieces. Worked like a charm!)

3) There's an extreme amount of satisfaction in getting one built and taking it to the range and firing it. I had a smile the whole time driving back from the range.

Anyway, this thread would be worthless without pics, so here goes. (Apologies for the mall ninja-ness/tacticool):






100 rounds at the range. 99 perfect shots and one misfire which I attribute to riding the charging handle back instead of releasing it and letting it slide home.

I did notice when I got home and went to clean it that part of the upper got dinged up a bit:



Wondering if this means the rifle is undergassed. I have an adjustable gas block but I believe it's set for allowing the most gas through. I was shooting American Eagle .223 55 grain FMJ.

Anyway, thanks again guys for all your encouragement. I know I have EBR fever now as I left the range and went to go buy another lower (BRO Fallout) even though I have no idea what I'm going to with it.

Enjoy your weekend!

(Oh, and hopefully my back up sights aren't on backwards!)

[SB1964]

The Dings are supposed to be there. That`s called a Brass Deflector, marks are normal. That have a Bullet Botton on it? can`t be sure, but looks like the stock Button??? Make sure of this one...

[BakaLogic]

The Dings are supposed to be there. That`s called a Brass Deflector, marks are normal. That have a Bullet Botton on it? can`t be sure, but looks like the stock Button??? Make sure of this one...

Cool beans, thanks!

It's got a Raddlock button on it and it's set so you have to use a tool to get the magazine out.

Planning on shooting it in Michigan so I went with the Raddlock so I could use it normally in free states.

[e] Also it's a blocked 10/20 mag that has been epoxied shut.

[atc4usmc]

Good looking build! Congrats

[BakaLogic]

Thanks!

[Dakine_surf]

Cool beans, thanks!

It's got a Raddlock button on it and it's set so you have to use a tool to get the magazine out.

Planning on shooting it in Michigan so I went with the Raddlock so I could use it normally in free states.

[e] Also it's a blocked 10/20 mag that has been epoxied shut.

Honestly I wouldn't epoxy the mags... It makes mags nearly impossible to clean. After your first carbine course, run n gun, or 3 gun competition, you will be bummed if you ditch your mags in the dirt and cant clean them. Also since you plan to shoot in free states just use the blocks.