Range Report - Kit-Built AR15 Lightweight Carbine


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Chris Rhines
March 14, 2004, 03:35 PM
A couple of months ago, I decided to buy an AR15-style rifle; being a tinkering sort of somewhat limited means, I decided to build one up from a parts kit. My favorite semi-local gun store, Quantico Arms (http://www.quanticoarms.com), was having a sale on the excellent Eagle Arms AR15 stripped lowers. I bought two for $75 each. After some consultation with folks on THR and elsewhere, I selected a J&T Distributing EM-4 (http://webcats.net/store/merchant.mv?Screen=PROD&Store_Code=J&Product_Code=AMMK&Category_Code=K) parts kit, with a standard A2 stock and chrome-lined barrel. I think I paid $540 for the parts kit, all told. I also bought some assorted tools from Brownells (www.brownells.com), including a set of roll-pin punches, a reversible vise block, and a DPMS barrel wrench.

I received the parts kit from J&T in about three days, quite fast by my thinking. I soon found out why: someone neglected to include the bolt carrier assembly in the package. Oops. A quick phone call to J&T resolved the matter (very good service, BTW) and I soon had the complete parts kit in my hot little hands.

The parts in question seemed to be of very good quality, with no casting voids, pits, or grinder marks. All the major part groups went together without binding or sticking - so far, so good.

Assembly was uneventful as the upper was already put together. I used the instructions from ar15.com to put the lower together, and had no problems (note - if you want to build an AR15, drop the thirty bucks for a set of roll pin punches. They'll save you a lot of swearing.)

The first major problem I ran into was while drilling the barrel for the muzzle break (I ordered a pre-ban upper, which was forty dollars cheaper.) Somehow, I managed to drill the "blind" hole for the muzzle break roll pin all the way into the bore.

Damn.

After the red haze of rage cleared from my vision, I considered my options. I could probably cut down the barrel to remove the newly perforated section, crown it, and then weld on a muzzle break to increase the barrel length up over Randy Weaver territory. That would work, but in the meantime I ordered a Bushmaster 16" Superlight post-ban barrel (http://www.bushmaster.com/shopping/barrel-assemblies/abbl-16sla.asp). Congratulating myself for my foresight in ordering that barrel wrench, I got it installed in a long afternoon. Not too bad.

Any idea of saving money by building a kit was by now swirling down the drain, but hey, I had a functioning rifle! I headed out to the local IWLA range to sight this monster in.

Well, sort of. Right from the start, I was plagued with constant failures to eject. Very annoying. I stripped the bolt down, relubed, and checked the ejector function. More failures to eject. WTH? Back down into the basement to try and sort out what is quickly becoming a real black hole for time.

I noticed, while dry-racking the rifle, that it was possible to hang up the bolt carrier by pulling the charging handle halfway back. Hmmm. Inspecting the inside, I found some strange wear marks on the tip of the hammer. I stripped down the lower, broke out the Swiss-pattern files, and took a little metal off the hammer. Reassembled, no more hang-ups. In fact, the entire bolt travel was much smoother. Hand-cycling some dummy rounds produced no more ejector failures.

Oh yeah, since I had the rifle apart, I decided that a quick trigger job was in order. I measured the trigger from the factory at a gritty 7#. I set the trigger in a small watchmakers vise, reduced the angle on the trigger nose about five degrees, then broke the corner and went over the engagement surfaces with fine, then extra-fine ceramic stones. The disconnector got cut down by about 0.100", and the engagement surfaces were polished with a bit of 600-grit sandpaper glued to a popsicle stick. Finally, I drilled a small hole 0.125" in front of the trigger slot, tapped it, and installed a small hex-head grubscrew as an overtravel stop. I applied a bit of moly-disulfide paste to the engagement surfaces, put everything back together, cranked the overtravel screw all the way in, then held the trigger back while backing out the screw. Once the trigger released, I backed the screw out a quarter-turn farther and fixed it with blue Loctite. Finally, I remeasured the trigger weight. Whew! 3.75#, smooth as glass, and no creep or overtravel. :D

So today, I head back to the range with 200 rounds of Q3131 and three Singaporean-surplus steel magazines. After I got to the range, I realized that I left the eyepiece for my spotting scope in my other shooting bag. Nuts. Still, I started out at 25 yards, just to get sighted in.

I loaded and chambered single round. BLAM!
Two rounds, this time. BLAM! BLAM! No full-auto, that's a good sign...
Five rounds. BLAM! BLAM! BLAM! BLAM! BLAM! I headed down to check out the target, and found a nice little 1" cluster, just about six inches low. Not bad for shooting off my elbows.
I cranked the front sight down eighteen clicks. Five more rounds, this time in another magazine. BLAM! BLAM! BLAM! BLAM! BLAM! All in the X-ring. Yes!
Full magazine this time. BLAM! x 28. No malfs. Bolt locked open after the last round. All my empties ejected into a two-foot circle. YES!

I only put about sixty rounds thru the AR today, and never got out to 100 yards. I'll save that for later. I'm pleased as punch with how my carbine performed.

I'd strongly recommend to anyone wanting an AR to try building up a kit. It's not hard at all, as long as you can manage not to put holes in the barrel, and you can save a few bucks and really learn how your rifle goes together. Plus, it's ten kinds of fun...

Here's a pic of the rifle in question, fully tricked out:

http://www.thehighroad.org/attachment.php?s=&postid=867816

It's wearing Trijicon tritium sights, a DPMS detachable rear sight, and a Wilderness Single-Point sling on a GG&G mount. Next accessory will be a scope of some kind. Any suggestions?

- Chrishttp://http://www.thehighroad.org/attachment.php?s=&postid=867816

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El Tejon
March 14, 2004, 03:44 PM
Wow! Aren't we becoming the gunsmith. Impressive.:)

Black Snowman
March 14, 2004, 04:37 PM
OK, scope decision time.
OK, 1st, what are you going to do with the rifle? (IE, plinker, HD, varmit, target, and at what ranges and in what conditions?)
2nd what's your optics budget? (Pretty self explanitory I hope)
knowing those two things you can narrow your choices from thousands down to dozens :)

Chris Rhines
March 14, 2004, 04:57 PM
El T - Thanks!

Black Snowman - Uses for the rifle will include reserve home defense (my present situation makes a carbine a good choice for that role,) and practical rifle and 3gun competition. Ranges probably won't exceed 100 yards, maybe 150 at the most. Conditions could be anything, and I want a scope that can handle just that...

My budget, say $500 including the mount. My means are somewhat less limited now. ;)

I'm leaning towards a 1x red-dot right now. Have looked at the Ultradot (very good, but the rings I have are way too short) and the Aimpoint ML2 (also very nice.)

- Chris

Black Snowman
March 14, 2004, 05:09 PM
Well, a dot sight sounds like a really good choice. Really any of the quality dots out there will do the trick. For longer ranges I recommend one of the small "target" dots rather than a larger "speed" dot or one of the dot sights with optional reticles or dot sizes. I'm not sure about the restrictions or requirements of practical or 3-gun so I'll keep my advice to a minimum ;)

Soap
March 14, 2004, 08:25 PM
Very nice!

DMK
March 14, 2004, 08:56 PM
Nice little AR. I love lightweight carbines. What does it weigh?

I always have a special place in the gunsafe for stuff I built myself. Having to work out a few kinks just makes the final result all that much sweeter.

Chris Rhines
March 14, 2004, 09:20 PM
DMK - It weighs just over seven pounds, loaded and slung. The scope will increase that somewhat, no help for that, but it's still incredibly light and handy.

- Chris

Thrash1982
March 15, 2004, 09:42 AM
Glad to see you got the AR worked out. Ian mentioned to me a while back what happened to your first barrel.

usp_fan
March 15, 2004, 10:02 AM
Nice rifle,

I've been wanting to build a lightweight upper for my kit built 20" A2 model.

One thing to think about, AR fire control groups are only surface hardened. If you take off too much metal while "fixing" the trigger pull, your fix may not last. The metal will be too soft to retain it's polish and shape for very long.

Just something to keep an eye on.

I buought my parts from j&t also. Great folks!

--usp_fan

Steve Smith
March 15, 2004, 10:54 AM
With all due respect, I echo usp_fan's comments. AR triggers are notorious for having a soft gooey center, not unlike a tootsie roll pop. (I think because they are all sintered and edge hardened?) Once you break through the hard cany outside, the rest doesn't last too long.

Onslaught
March 15, 2004, 11:24 AM
Quick question....

What's the weight difference (perceived, if that's all you got) between the rifle wearing an M4 barrel compared to Bushy's super-light bbl?

If you try a red-dot, look at OKO sights. They're SUPER light, and excellent quality. I've been very pleased with mine, as are most folks who try them.

Thanks.

Chris Rhines
March 15, 2004, 08:42 PM
Steve and usp_fan: You guys have piqued my curiosity. As soon as I can get my mitts on another AR15 trigger, I'm going to section it on my bandsaw and Rockwell test the hardness on the inside. I'll post my results.

Onslaught: The superlight barrel knocked maybe half a pound off the overall weight - more than I thought it would.

- Chris

atek3
March 18, 2004, 11:27 PM
Nice work chris.

BTW how did you manage to drill all the way through to the bore?

atek3

artherd
March 19, 2004, 01:11 AM
I would VERY much like to hear your accuracy results with a scope and sandbags. (and if you can with the 77gr Black Hills load that the US Special Forces is testing now in combat with good results.)

Very intrested in how this exact barrel performs.


I would put an EOTech on your flat-top, you have a very nice carbine!

Best!
Ben.

talbalos
March 19, 2004, 01:28 AM
"I would VERY much like to hear your accuracy results with a scope and sandbags. (and if you can with the 77gr Black Hills load that the US Special Forces is testing now in combat with good results.)"

This stuff?

http://www.georgiaprecision.com/cart/images/BHANato1.jpg

Only $349 for 500 rounds from Georgia Precision (http://www.georgiaprecision.com/cart/items/BHANatoAmmo.htm)

artherd
March 19, 2004, 02:19 AM
talbalos- yes, that's it.

I realize it's expensive, but a good choice for defensive ammo out of a 16" barrel.

There is also a .223REM commercial loading of the 77GR OTMs (about 100fps off the mk262 mod1 5.56) that's much cheaper.

talbalos
March 19, 2004, 03:00 AM
The difference is the cannelure in the bullet. This is critical for military semi auto, mag fed use. Allows the case neck to be crimped down to grip the bullet and minimize the possibility of it getting pushed back into the case. This can happen due to recoil.

Since the commercial bullets don't have cannelure and the military specifies them, manufacturers are making special runs of their projectiles. Hence the higher price.

As for "defensive" use, the DoD is testing it for long range use in the mountains of Afghanistan. The M855 wasn't cutting it at the distances troops have been engaging targets.

For home defense, more power to you if you can afford to pay $35 for 50 rds. I easily go through 100 rds of 5.56 per range trip. The best ammo in the universe isn't going to do you a lot of good if you don't familiarize yourself with its ballistic performance, and to do that you have to shoot it. You can read all the reports, articles and websites you want, but it's no replacement for actual field use.

For the price of 1,000 rds of the Black Hills you can get over 4,000 rds of Winchester Q3131A or Federal XM193 which is fine for a SHTF MOUT scenario.

Snowjob
March 19, 2004, 05:05 AM
Yikes. I was hoping to assemble an AR but am now beginning to wonder whether that would actually be a wise idea. I don't feel fully confident about assembly that calls for drilling and other (potentially expensive)alterations. Should I expect a similar experience, or is this more with stripped receivers and kits, as opposed to assembled upper and lower? Or perhaps characteristic of parts from particular companies?

Bartholomew Roberts
March 19, 2004, 12:25 PM
I don't feel fully confident about assembly that calls for drilling and other (potentially expensive)alterations. Should I expect a similar experience, or is this more with stripped receivers and kits, as opposed to assembled upper and lower?

You can buy ARs in various states of assembly. With a pre-assembled upper and pre-assembled lower, even a 3yr old can put one together. Most people who can operate a screwdriver can assemble the lower with few problems (though I have seen the occasional exception to this rule).

The uppers can be a bit trickier but are usually bought pre-assembled. In this case, the only purpose for drilling was to install a muzzle-brake on a post-ban weapon. In most cases you can buy the barrel with the brake already installed if you wish.

talbalos
March 19, 2004, 12:43 PM
Snowjob: "Yikes. I was hoping to assemble an AR but am now beginning to wonder whether that would actually be a wise idea."

Building an AR-15 is actually pretty easy. I've built up several rifles and I've never had to do any drilling or filing.

Chris is right, the roll pin punches do make installation much easier. However I was able to find them indivually at a store dedicated to tools, and it cost me less than $15 to get what I needed.

I put my last lower together on my dining room table in less than an hour. The instructions and tool list at arfcom are good enough:
http://www.ar15.com/content/docs/assembly/lower/

A copy of TM 9-1005-319-23&P is good to have.

Putting an upper together takes awhile longer because I have to drive over to a friends house to use his vise. You can avoid that by buying a preassembled upper. You're not really missing much of an experience if you go that route.

Chris only had to drill because he wanted to permanently install a muzzle brake on a pre-ban threaded barrel himself (BTW in order for it to be fully post-ban compliant, he would have to remove the bayo lug from the bottom of the ront sight base). In the end, he wound up getting another barrel (A post-ban)

Third_Rail
March 19, 2004, 01:03 PM
Hmm. Is it legal to assemble a rifle like this in MA as long as one has the license for the rifle?

I can see saving a whole bunch of money... but I'll still have to look around for the stripped receiver, parts kit, etc.

Snowjob
March 19, 2004, 04:17 PM
Thanks for the reassurance and further information.

artherd
March 19, 2004, 09:01 PM
The difference is the cannelure in the bullet.

Ah, gotcha. I did think the commercial BH had the cannelure, but can't remenber for sure.

The mk262 mod0 lacked the cannelure, the mod1 was to add it.

Chris Rhines
March 19, 2004, 09:20 PM
Chris only had to drill because he wanted to permanently install a muzzle brake on a pre-ban threaded barrel himself (BTW in order for it to be fully post-ban compliant, he would have to remove the bayo lug from the bottom of the ront sight base). Exactly. And I should mention (before the BATmen kick down my door) that I did indeed remove the bayonet lug before assembling the rifle. I'm always very careful to obey the law... :evil:

Snowjob - If you can get on the internet and post messages to an online forum, then you have all the technical wherwithal you need to build an AR-15 up from a kit. All the drilling and filing I did was for my own benefit; you can assemble an AR from a kit and stripped lower without even owning a file or drill.

- Chris

PUMC_TomG
March 26, 2004, 12:36 AM
Crafty!

I'll be looking to help you to help me with the 3-gun/HD AR I've been wanting for the past year....

Looks like your skills are improving.... I'll be bracing myself for an appearance by "Rhines Customs" in SWAT magazine in a few years. ;)

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