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View Full Version : AR-15 in 7.62x39, who has one?


Brenten
December 30, 2009, 06:33 PM
Wondering what everyone who owns one thinks of it and how reliable they are. One big complaint was reliability in these guns and I think it all stemmed from bad magazines and some bolt/extractor compatibility issue. So who has one, what brand and how do you feel about it?

allons
December 30, 2009, 08:03 PM
I've owned three for over 10 years now. Just gave one to my youngest son, so now I'm down to these two in the pics.

http://i106.photobucket.com/albums/m249/Allons11/british/th_british017-1.jpg (http://i106.photobucket.com/albums/m249/Allons11/british/british017-1.jpg)
http://i106.photobucket.com/albums/m249/Allons11/british/th_british020.jpg (http://i106.photobucket.com/albums/m249/Allons11/british/british020.jpg)

All of mine are Model 1 Sales 7.62x39 Kits, built on Superior Arms stripped lowers. The magwells on the Superior have pretty consistent dimensions, they run a little tighter and you REALLY don't want a sloppy mag fit in this cal.

As far as reliability, never had any problems that weren't mag related in over 15,000 rds of corrosive ammo thru the 3 rifles. When I built my first two, I bought 2 extra bolts because I had heard they were prone to breakage, never had to use one yet! It helps if you use the higher power hammer spring, some of the surplus and Silver Bear ammo have tough primers.

Once you get the mag thing figured out, they run 100%. DPMS Franken mags are the only ones I've found that worked perfect every time, right from the package, in all my rifles. The last generation CProducts mags work pretty good, but I still had to tweek the feed lips a little.

If you pretend you are shooting a very accurate, semi-auto 30-30 rifle, thats about what the trajectory figures to be. Mine eat anything, but the Yugo brass cased surplus is the most accurate I've found. Keep e'm CLEAN!

Short answer, I like mine, glad I got them, will always keep them, but since we started playing with the 5.45x39 ARs, they don't get much range time, that little rd makes it a whole different type of weapon though. Good Luck, Ken

1832
December 30, 2009, 08:35 PM
I've had a Model 1 complete upper w/20"bbl for going on two years now and probably have about 2100 rds through it. The only change I made was not to get the Model 1 carrier & bolt and went for an MGI Enhanced Bolt instead. I don't care for using heavier hammer springs and doing firing pin mods. I've never had a failure to fire with the MGI Bolt and I use the steel cased ammo exclusively in it. It seems to be most accurate with the Brown Bear HP ammo.

Brenten
December 30, 2009, 10:22 PM
interesting, thanks, seems like all issues are mag related not gun related. so franken mags are best.

MMcfpd
December 31, 2009, 12:24 AM
I just assembled my third. A brief summary of what I know about them:

Barrels are currently available from:
- Bushmaster (chrome lined)
- J&T/Doublestar (chrome lined? - web site lists chrome moly)
- Model 1 Sales (chrome moly)
Less readily available barrels are offered by:
- ArmaLite (chrome lined)
- Olympic Arms (stainless steel)
- MGI (?)

As far as I know all are 1:10 twist. Nobody offers a lightweight. Bushmaster and ArmaLite barrels are M4 profiles, most of the rest are HBAR and 16", but Model 1 and J&T offer 20" barrels. Model 1 has pistol barrels as well. ArmaLite's is the only middy of which I'm aware. Colt did make some 1:12 barrels, but they are out of production.

Model 1 and J&T barrels seem to be the most widely used with few complaints; less feedback is available on the rest.

Difficulties commonly encountered with operating an AR-15 configured for 7.62x39mm have included:
1.) Reliable magazines
2.) Bolt breakage
3.) Firing hard primered steel case ammo (Wolf, Barnaul, etc.)

Magazine solutions tried have involved:
- C Products new production magazines - 5 & 10 round versions work well, 30s work with qualifiers noted in this and other threads
- Standard 5.56 magazines with 5 or 6 rounds loaded
- Colt 5 round magazines - out of production
- MWG plastic 5 & 10 round magazines - hit or miss - some like them while others (like me) have had no luck with them
- National magazines - don't bother
- Frankenmags - so called because they have an AR magazine top combined with an AK magazine body; they are all out of production but were made by USA, G-Tech* and Scherer in 20 and 30 round capacities - they work but must be hunted down on the used market
- AK-47 magazines - two different lowers - the out of production AR47 and MGI's modular lower - have been made to allow use of AK-47 magazines. My impression is that this is an awkward and expensive route to take.

Bolts are available from a variety of sources. LMT's out of production but still (I think) available lobster tail bolt seems to be the durability king, but AR Performance has a relatively new entry in this market niche that looks interesting. There's not much feedback on the AR Performance bolt yet. Besides being beefy, it is notable that it is designed to use standard extractors.

MGI makes a bolt/firing pin combo enhanced for firing the hard primered eastern european steel case ammo. The bolt face has a larger firing pin hole and the firing pin itself is profiled to protrude farther from the bolt face allowing a deeper strike on the primer. It works, but mine's extractor broke after ~1100 rounds and MGI has been unable to come up with a replacement extractor.

Other approaches to firing the steel case ammo include machining modifications to the head or tail of the bolt or the firing pin as well as using different (Wolff) hammer springs. These variations are all meant to produce a deeper and/or more forceful primer strike.

My most used 7.62x39 AR has an M1S (ER Shaw) barrel lightened and cut to 14.5" with an SDI extended FH pinned and welded, all barrel work done by ADCO. With an LMT bolt and a Geissele SSA trigger, it fires brass 100%, Monarch almost 100% and Wolf about 50%. And it is quite accurate. It is one of my favorite guns.

One I've just assembled but have not yet fired uses a Bushmaster barrel with an LMT bolt and a Geissele DMR trigger. Optimistic sort that I am, I anticipate good results. Lurking out there in the future is my backordered ArmaLite barrel, with which I may try one of the AR Performance bolts.

rbernie
December 31, 2009, 12:32 AM
I've built five or six of them over the years, and hunted quite extensively with one of them for most of the last decade. I tend to only shoot brass-cased handloads, and have been quite pleased with the accuracy and reliability of the ones I built. I gravitate towards 16" carbines, and the one disappointment that I had was a 20" M1S barrel that short-stroked on me with most any ammo. Others have made the 20" work for them, but for me it was a bust and I use the shorter barrels.

MMCfpd has given you a great synposis. The only thing that I can add is that I have found the latest C-Products hi-cap magazines to be quite reliable and useful (which finally addresses the biggest complaint about the 7.62x39 chambering in an AR).

Brenten
December 31, 2009, 01:06 AM
excellent info, I will add that I have been looking into an already built model and the ones I found are as follows:

http://www.olyarms.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=52&category_id=22&manufacturer_id=0&option=com_virtuemart&Itemid=37&vmcchk=1&Itemid=37

http://www.dpmsinc.com/store/?cat=1923

http://www.armalite.com/ItemForm.aspx?item=15A4C-7.62X39&ReturnUrl=Categories.aspx?Category=8e8e5de6-5022-483e-812b-822e58014822

http://www.model1sales.com/item-detail.cfm?ID=KCE762&storeid=1&image=car16pre762.gif&CFID=56735003&CFTOKEN=72553778

http://www.gunblast.com/Doublestar-762x39.htm

http://www.del-ton.com/AR_15_Rifles_s/2.htm

Lloyd Smale
December 31, 2009, 08:52 AM
i just got a new bushmaster in 762x39. I had problems out of the gate with feeding. Most all of my ammo would nose dive into the feed ramp. I had the one factory bush. mag and 6 30 round c products. mags. they all did it. I tried some reshaping and polishing on the feed ramp and that helped but didnt cure it. I then sent the gun back to bushmaster. they further reshaped and polished the feed ramp and replace all the mags including the c products mags with new bushmaster mags. the mags i got back obvioulsy had stiffer springs in them. I had heard on the iternet that replacing the springs with wolf extra power ak47 mag springs was a fix and had bought a few but didnt end up needing them. I have a few extra power hammer springs but havent installed them as i havent had a missfire in the 500 rounds of wolf ive put through it. Ive heard about the bolt troubles but have no idea if bushmaster addressed this or not but ive got extra bolts for the rest of my ars and will probably buy one for this gun too anyway. Right now the gun runs perfectly. Its becoming my favorite ar. I love going to the range and shooting 2 or 300 rounds and not having to pick up brass!!