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Posted: 5/3/2007 7:16:01 PM EDT
[Last Edit: 5/7/2007 4:53:26 PM EDT by Molon]
Competing With the Past


Thirty years ago this month, the article “AR-15 Match Loads” by Al Miller was published in Handloader magazine. As you would expect, the article chronicles Al Miller’s endeavors in developing accurate loads for the AR-15. The AR-15 he used in developing his match loads was an A1 version. (Did I mention this was done 30 years ago?)





Even though the M16A2 replaced the M16A1 as “Standard A” for the U.S. Military in November of 1983, the A1 has several characteristics that many people still find desirable today. Foremost would probably be the light weight of the rifle, which is due in no small part to the A1 barrel. The A1 barrel weighs several ounces less than an A2 government profile barrel (and one pound, 4 ounces less than an HBAR). Comparing the profile of an A1 barrel to an A2 barrel, we see that the weight reduction occurs in the area from the gas block to the muzzle.





Another feature of the A1 model that many people like is the simplicity of the rear sight. It is a “set it and forget it” affair with adjustment for windage only.





A third feature of the A1 model often mentioned is the shorter length of pull when compared to the A2 model. The A1 stock is 5/8” shorter than the A2 stock. [While the A2 stock is longer than the A1 stock, it is made of improved materials making it 10 to 12 times stronger than the A1 stock. (All the better to butt-stroke you with, my dear!)]


I have an unfired, 20” Colt A1 barrel assembly in excellent condition that I’ve been saving to use for a 20” KISS type build. As Colt introduced the first AR-15 A2 model to the civilian market around 1984 and stopped producing the A1 Sporter model around 1985, I’m going to take a S.W.A.G. and say that the A1 barrel that I have is over 20 years old! The barrel is stamped “C MP CHROME BORE” and has a 1:12” twist.





While I wanted to keep this KISS build as reasonably light as possible, I did want to make a few changes from the standard A1 configuration. One complaint generally heard against the A1 barrel is that it is “not very accurate,” though most often the complaint is made without any quantifying data being presented. Also, the A1 model uses the triangle handguards that are known for having poor heat dissipation and easy breakage. I decided to replace the triangle handguards with a 1st generation JP Enterprises free float tube to aide in heat dissipation and in ringing out all the available accuracy of the A1 barrel. The JP tube and barrel nut replace the triangle handgurads, handguard endcap, barrel nut and delta ring assembly. The JP free float tube and barrel nut actually weigh 1 ounce less than the original parts that they replace.





While I like the simplicity of the windage-only feature of the A1 sight, I prefer the sight aperture of the A2 sight. The “long distance” aperture of the A2 sight is about 0.010” smaller than the A1 aperture and the A2 aperture also has the “ghost ring” aperture for up close/low light shooting that is lacking on the A1 sight. Enter, the LaRue Tactical Back Up Iron Sight. This sight uses an A2 aperture but has adjustments for windage only; exactly what I was looking for. The sight attaches to the Picatinny rail of a flat-top upper receiver using LaRue’s throw lever mount.





You’ll notice in the last sentence that I said flat-top upper receiver. An A1 upper receiver weighs 9.9 ounces. An A4 flat-top upper receiver with the LaRue BUIS attached weighs 11.5 ounces for a difference of 1.6 ounces. Using the JP free-float tube along with the flat-top upper receiver and LaRue BUIS for this build gives me a net weight gain of only 0.6 ounces more than a standard A1 upper group. It also gives me the option of adding optics to the flat-top upper receiver and rails in just about any position I might need them on the JP free-float tube. Even though the LaRue sight is referred to as a back-up sight, I’ll be using it as the main sight on this KISS build.


The completed 20” KISS build weighs in at 6 lbs 15 oz. Here are a few pics of the the build.


























For his article “AR-15 Match Loads”, Al Miller used six different powders and five different bullets in testing, including Sierra’s 52 grain boat-tail hollow point bullet. He tested his loads off a bench at 100 yards using front and rear bags and a scope. His groups ranged from 0.75” to 2.75”. Unfortunately, he did not fire any 10-shot groups (I guess he didn’t get the memo.) All of his groups consisted of 5 shots each.

Using his best tuned load, Al Miller turned in ten, 5-shot groups that had an average extreme spread of 1.075”. While these were only 5-shot groups, I was extremely impressed that he was able to obtain that level of accuracy using an A1 barrel. I was curious to see how my twenty year old A1 barrel would stack-up against his. (Obiously, I had an advantage with the free-float tube.)

Using one of my standard handloads for Sierra’s 52 grain MatchKing, I fired ten, 5-shot groups in a row from the bench at 100 yards (using front and rear bags and a scope) with the following results:

0.81”
1.10”
1.04”
1.34”
0.66”
0.73”
1.01”
0.98”
0.93”
1.08”

The average extreme spread for my ten groups was 0.968”. Following my standard protocol for accuracy testing, I also obtained three 10-shot groups from 100 yards that measured:

1.39”
1.26”
1.40”

Those three, 10-shot groups had an average extreme spread of 1.35” and more importantly the three groups overlayed on each other using RSI Shooting Lab had a mean radius of 0.45”. Here are some pics of the best groups.















In 1964, during testing for report number DPS-1471, the US Military conducted accuracy testing of production M16 rifles (which had the same barrel as the M16A1.) With the rifles secured in a machine rest, three 10-shot groups were fired (hmm . . . where have I heard that before) from 100 yards using M193 ammunition. “The average extreme spread of the groups ranged from 2.6 to 3.6 inches.”

For nostalgia sake, I fired three, 10-shot groups of IMI M193 off the bench at 100 yards from my A1 barreled upper. The average extreme spread of the three groups was 3.00”.

Link Posted: 5/3/2007 7:30:45 PM EDT
Excellent post. Great shooting too, shows these GI barrels are capable of some great accuracy...
Link Posted: 5/3/2007 7:42:54 PM EDT
Great post

Link Posted: 5/3/2007 7:51:07 PM EDT
I'm having a hard time beleiving you, please send me the rifle so I can verify your report.
Link Posted: 5/3/2007 7:52:33 PM EDT
[Last Edit: 5/3/2007 7:53:18 PM EDT by JJREA]
Very, very nice post.

We have alot in common. My brothers fulton armory Legacy is one of my favorite AR's. But I like the A2 apertures and I'm not too fond of hanging on to those triange handguards. You built yourself a winner. There's nothing like a good 20"er. Even when we're swimming in a sea of carbines.

And oh yes, I think the A1 stock is the ultimate length.
Link Posted: 5/3/2007 8:25:35 PM EDT
TAG.

That's some good shooting with iron sights.

Stock trigger, too?
Link Posted: 5/3/2007 8:28:27 PM EDT
I've always liked the concept of free floated A1 profile barrels... glad to see I'm not the only one, and that it works as well as I thought it would

Excellent work. and post.
Link Posted: 5/4/2007 5:14:28 AM EDT
Never ceases to amaze me the difference between match/handloads and mil-spec ammo: about 3x the accuracy according to your test (1 MOA vs. 3 MOA). You'd think that the mil-spec stuff would be made to tighter specs than it is.
Link Posted: 5/4/2007 6:50:16 AM EDT

Originally Posted By ABNAK:
Never ceases to amaze me the difference between match/handloads and mil-spec ammo: about 3x the accuracy according to your test (1 MOA vs. 3 MOA). You'd think that the mil-spec stuff would be made to tighter specs than it is.


I believe its simply a diminishing returns type of deal. Tight groups are great, but at what point does it become too expensive to just hit a man out to 3-500 yards. Milspec ammunition accomplishes this so I guess its good enough.
Link Posted: 5/4/2007 7:42:09 AM EDT
We have similar thinking. My two A1 carry-handle uppers circa. late 70's both wear A2 stocks and handguards (the better to butt-stroke you with!). Simple and ought to be effective. Some say that the A1 barrels can be capable of surprising accuracy. The only downside is the barrel twist/bullet weight limitations, but that doesn't concern me too much for home defense purposes.

I like the LaRue BUIS and free-float handguard ideas. Good show!

dvo
Link Posted: 5/4/2007 4:20:08 PM EDT

Originally Posted By HP40:
I'm having a hard time beleiving you, please send me the rifle so I can verify your report.


Verification is the bedrock of the scientific method!
Link Posted: 5/4/2007 4:20:56 PM EDT

Originally Posted By skywarp989:
TAG.

That's some good shooting with iron sights.

Stock trigger, too?


I wish! All accuracy testing was done with a scope; a Leupold Vari-X III to be exact.
Link Posted: 5/4/2007 4:43:42 PM EDT
I like your design very much: clean, simple, and lightweight.

My favorite is my retro slab side USAF M16 upper, with, believe it or not, a 1:7 twist A1 barrel.
Link Posted: 5/4/2007 7:06:25 PM EDT

Originally Posted By AtlantaFireman:
I like your design very much: clean, simple, and lightweight.

My favorite is my retro slab side USAF M16 upper, with, believe it or not, a 1:7 twist A1 barrel.


I thought the Unicorns took all of those with them when they left. Can you post some pics of your barrel markings?
Link Posted: 5/4/2007 7:14:34 PM EDT
[Last Edit: 5/4/2007 7:19:47 PM EDT by AtlantaFireman]
Yes. Give me two days or so. I have a Garand match on Saturday and a Vintage Bolt Rifle match on Sunday. After that, I post detailed photos. For the time being, here is my web page about it. Slab side retro

Personally, I think that if some company got around to making these 1:7 twist A1 barrels with correct FSB, they would sell like hot cakes.
Link Posted: 5/4/2007 7:29:46 PM EDT
Awesome. Thanks for the good read, and great photos.
Link Posted: 5/5/2007 6:45:50 AM EDT
[Last Edit: 5/5/2007 8:17:47 AM EDT by Molon]

Originally Posted By AtlantaFireman:
Yes. Give me two days or so. I have a Garand match on Saturday and a Vintage Bolt Rifle match on Sunday. After that, I post detailed photos. For the time being, here is my web page about it. Slab side retro

Personally, I think that if some company got around to making these 1:7 twist A1 barrels with correct FSB, they would sell like hot cakes.


I'd buy one!
Link Posted: 5/5/2007 8:07:24 AM EDT

Originally Posted By AtlantaFireman:


Personally, I think that if some company got around to making these 1:7 twist A1 barrels with correct FSB, they would sell like hot cakes.




bushmaster did a run of SL 1/7 barrels with the FSB for a1/a2 uppers. they still have a few left.
Link Posted: 5/5/2007 8:19:07 AM EDT

Originally Posted By fegsa85:

Originally Posted By AtlantaFireman:
Personally, I think that if some company got around to making these 1:7 twist A1 barrels with correct FSB, they would sell like hot cakes.

bushmaster did a run of SL 1/7 barrels with the FSB for a1/a2 uppers. they still have a few left.

Those were 16" carbine gas though.
Link Posted: 5/5/2007 8:22:25 AM EDT
I have been tyring to looby SOMEBODY to manufacture A1 profile 20" 1/8 or 1/7 barrels for a while! I don't understand why anybody would NOT want a A1 profile barrel in any length, unless it is a dedicated presicion rig.
Link Posted: 5/5/2007 10:14:05 AM EDT

Originally Posted By Molon:

Originally Posted By AtlantaFireman:
I like your design very much: clean, simple, and lightweight.

My favorite is my retro slab side USAF M16 upper, with, believe it or not, a 1:7 twist A1 barrel.


I thought the Unicorns took all of those with them when they left. Can you post some pics of your barrel markings?


Here's one.....

Link Posted: 5/5/2007 10:27:37 AM EDT

Originally Posted By Villafuego:

Originally Posted By Molon:

Originally Posted By AtlantaFireman:
I like your design very much: clean, simple, and lightweight.

My favorite is my retro slab side USAF M16 upper, with, believe it or not, a 1:7 twist A1 barrel.


I thought the Unicorns took all of those with them when they left. Can you post some pics of your barrel markings?


Here's one.....
img.photobucket.com/albums/v239/villafuego/retroAR.jpg
img.photobucket.com/albums/v239/villafuego/bblmarks.jpg


I'd love to get my hand on one or two of those.
Link Posted: 5/5/2007 1:04:20 PM EDT

Originally Posted By Villafuego:

Originally Posted By Molon:

Originally Posted By AtlantaFireman:
I like your design very much: clean, simple, and lightweight.

My favorite is my retro slab side USAF M16 upper, with, believe it or not, a 1:7 twist A1 barrel.


I thought the Unicorns took all of those with them when they left. Can you post some pics of your barrel markings?


Here's one.....
img.photobucket.com/albums/v239/villafuego/retroAR.jpg
img.photobucket.com/albums/v239/villafuego/bblmarks.jpg


That is beyond cool!
Link Posted: 5/5/2007 2:05:46 PM EDT
Another great thread by Molon!
Link Posted: 5/5/2007 2:06:19 PM EDT
Excellent report and pics. Great looking upper too. I've been wanting to do something like that. You've just inspired me I already have a barrel available I just need to pick up a flat top upper and full float handguard.

Thanks,
Rick
Link Posted: 5/5/2007 5:17:46 PM EDT

Originally Posted By Villafuego:

Originally Posted By Molon:

Originally Posted By AtlantaFireman:
I like your design very much: clean, simple, and lightweight.

My favorite is my retro slab side USAF M16 upper, with, believe it or not, a 1:7 twist A1 barrel.


I thought the Unicorns took all of those with them when they left. Can you post some pics of your barrel markings?


Here's one.....
img.photobucket.com/albums/v239/villafuego/retroAR.jpg
img.photobucket.com/albums/v239/villafuego/bblmarks.jpg


Your rifle looks EXACTLY like mine. I love it!
Link Posted: 5/7/2007 4:27:29 PM EDT
Sometimes it’s the simplest things that impress me the most. This particular time, it’s the LaRue BUIS. This thing is the cat’s a$$.

I zeroed the sights on this new upper at 50 yards for an Improved Battlesight Zero. Using the Larue BUIS gave a sight picture just like that of an A2 upper. Here’s a pic of one of the zero targets from 50 yards.





Here are a few more pics of the LaRue sight.














Link Posted: 5/8/2007 7:42:51 AM EDT
OST
Link Posted: 5/30/2007 10:37:10 AM EDT
OSB

(Old School Bump)
Link Posted: 8/14/2007 8:43:55 AM EDT
^
Link Posted: 8/14/2007 3:38:21 PM EDT
how much did the rifle wiegh with the leupy vx-III mounted?
Link Posted: 8/15/2007 11:55:03 AM EDT

Originally Posted By brewsky101:
how much did the rifle wiegh with the leupy vx-III mounted?


The VX-III adds another 27 ounces to the mix.
Link Posted: 8/15/2007 3:40:06 PM EDT
Link Posted: 8/16/2007 3:55:44 AM EDT
You know, I wouldn't have thought about a build like that myself but it came out nice! I could think of a lot of uses for a build like that even though I'm still not crazy about the 1/12 twist barrel.
Link Posted: 8/16/2007 12:13:41 PM EDT

Originally Posted By LaRue_Tactical:
I see that the "OST" has been bumping around for awhile.

Molon,

Good stuff.

But shoot just 3-shot groups next time.

ML


I know a guy who shoots 2-shot groups.
Link Posted: 8/16/2007 6:19:29 PM EDT

Originally Posted By Molon:

I know a guy who shoots 2-shot groups.


A 2-shot group...isn't that an oxy moron?
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