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ACCURIZING A KALASHNIKOV RIFLE


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#1 my762buzz

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Posted 15 January 2010 - 12:03 AM

ACCURIZING A KALASHNIKOV RIFLE
By R.W. Parker
copyright 2004 Precision Shooting Magazine



(Editor’s Introduction: Usually a would-be new writer is well advised to call the grouchy old Editor before putting pen to paper for the creation of his possible second coming of Gone with The Wind. It’s just possible that the Editor hates the proposed idea and wouldn’t publish such an article if it was the last available article in the world. This may hurt the fellow’s ego, to say nothing of his dream, but it sure cuts down on the wasted time.

Thus it was when I saw the manuscript Accurizing A Kalashnikov Rifle come through our mail slot here at the PS office. “Why,” I wondered, “didn’t this ninny call me first? No matter, it’s going back to him in the afternoon mail out of here.” No intention of even looking at the darn thing; we’re a person of strong convictions and the stubbornness level of an intransigent mule with a toothache.

Don’t ask me why…maybe some feeling of a bit of guilt…that just possibly I owed the writer at least the most cursory of looks at the manuscript. Perhaps a couple of minutes, at the outside. Certainly no more. Let’s not overdo the graciousness…do it once and they’ll expect it all the time.

Thirty minutes later we had finished reading the article. Mumbling something about “I don’t believe this” we then re-read it. The wonder re-read was a wonder still. We didn’t think that a piece on this topic could possibly be anything but entry level stuff, hardly the dare to put in front of our readership, persnickety group of (censored)s that they are. Wrong!

We are of course aware of the evolution of the AR-15 as an accuracy rifle. At the time of the Ar-15’s birth it was considered marginally accurate enough for gunfights where both parties were inside the same phone booth. A cottage industry grew up around the (strange) idea of improving their accuracy level. Today they absolutely dominate Highpower shooting up to and including the 600 yard stage, and there’s a very large number of seemingly sane souls who say the figure cited should be “1000” and not “600.” We’ll be darned if we’ll stick our nose into that one.

That 100 yard, 5 shot target herewith measures .675". It’s not going to win the Super Shoot this year…but an AK-74???!)



After I graduated from the Colorado School of Trades gunsmithing program in 1982, I spent a few years working for a couple of well known custom gunsmithing outfits. The work was enjoyable, but the pay sure wasn’t making a dent in my student loan. So, in order to make ends meet, I took a job as an apprentice machinist. I job-hopped in the machine trades for a number of years, ending up as a Class “A” Toolmaker, but all the while I was still doing gun work as a sideline. About four years ago however, the future started looking pretty bleak in the Tool & Die trade. Some of my friends who were top-flight Toolmakers now found themselves in jobs that paid scarcely more than minimum wage. Fortunately, I had put together a small machine shop of my own over the years and, before throwing in the towel and applying for a job at Wal-Mart, I decided to make a last ditch stand. I got an FFL, and started Parker Arms & Tool Works.

My shop is a lot like the ones I enjoyed visiting as a kid - nothing fancy, just a working shop that feels comfortable. Situated in rural Pennsylvania, customers enter directly into where the work goes on - there’s no store or waiting room. When time permits, I enjoy holding court in the shop with my “regulars”. Since we’re all gun nuts, many of my customers have also become good friends. Much of my work involves military arms (mostly communist-bloc stuff), but the daily workload here is rather diverse. Jobs range from repairs on “huntin’ irons” to complete restorations of classic guns, as well as custom built rifles and handguns. In fact, the work that I receive is of such a variety that I long ago decided it would be pointless to produce a catalog or brochure. My customers usually just come to me with their ideas, and I build what they want.

The Kalashnikov rifle featured here represents the fruition of one such idea. It grew out of an interesting conversation between my friend John and I one afternoon. John is a Mechanical Engineer of exceptional ability, and we met years ago when he hired me to build dies and tooling for a major vendor to the medical and aerospace industry. Since we both had “guns-on-the-brain” and a love for precision work, we quickly formed a friendship.

Anyway, the conversation that sparked the idea for this rifle was prompted by an article in a gun magazine about modern assault rifle cartridges. In the article, the author claimed that the Kalashnikov design could never approach the level of accuracy that an AR15 is capable of achieving - “period”. When I read this, I thought that it was a bit of a stretch. Having an excellent working knowledge of both guns and things mechanical, John was also intrigued by such a claim. I’m well known as a Kalashnikov nut, so John asked me what my thoughts were.

“Well, in the AK, there’s a high ratio of mass between the bolt and bolt carrier assembly”, I told John. “While that’s one of the reasons that the AK is so reliable, the reciprocation of that heavy bolt carrier during the operating cycle is usually blamed for its lack of accuracy”, I explained.

“But essentially” John said, “the AK action does the same job as Stoner’s design - albeit in a different fashion, no? It strips a cartridge from the magazine, chambers it, seals the breech, fires it, then extracts and ejects the spent case. I’d bet that if you dampened the operating system somewhat, a Kalashnikov could be made to shoot as well as an AR15”.

That struck me as a logical assumption. The AR15 is certainly an inherently accurate design and, since they became popular for competitive shooting, a zillion aftermarket manufacturers making match-grade components for these guns sprang up - as well as a number of ‘smiths who build accurized AR’s. Getting an AR15 to shoot is pretty much “plug-and-play”, compared to building an accurate AK. “I’d venture that’s got more to do with the AR’s reputation for accuracy, than any alleged insurmountable problem with the Kalashnikov design”, I told John. “In fact, once you quieted down the operating system, you could just address the usual concerns - barrel, sights, trigger, and ammunition. I wouldn’t doubt that an AK could be made to shoot if you really worked it over.”

John smiled. “So what do you think, Rich? Want to give it a try?” He knew that I enjoyed a challenge, probably because of all the problems that we used to solve together in the toolroom. I was certainly excited about the prospect of turning an AK into a tackdriver. “However,” I cautioned John, “this could get a bit more expensive than accurizing an AR, simply because many of the required components would have to be built from scratch.” John wasn’t deterred by this, so we struck a deal and I set about developing a concept for the rifle.

The first thing I had to consider was which cartridge to use. While I assemble semi-auto AK’s and AKM’s that shoot a bit better than “rack grade” Kalashnikovs, the AK-74’s I’ve built (in 5,45x39mm) always seemed to have an edge on the 7,62 caliber rifles. The Russians adopted the 5,45 caliber round primarily to reduce shot dispersion on full-auto, but I decided that using a “low-impulse” cartridge would also make sense in an accurized AK.

I ruled out the using the 5,56 NATO, primarily because I wanted to stick with commonly available magazines. Also, I wanted to use as many “off-the-shelf” AK parts as possible, to simplify the rifles construction. Decent iron sights could be made up for an AK, but ultimately I’d have to incorporate a rigid mounting system for a telescopic sight. Ron Power developed the excellent “Red Star” adjustable trigger for the Kalashnikov, so I knew that some of the variables affecting accuracy could be addressed without too much trouble.

However, if I wanted to use the Russian 5,45x39mm cartridge, there’d still be a problem: the lack of match grade projectiles. I also wanted to use a heavy barrel on the project - which wasn’t a problem, as Lothar Walther makes barrels in 5,45 caliber. But the only projectiles available in this caliber were “ball grade” bullets that were already loaded in factory ammunition, and there still wasn’t a whole lot of variety to choose from. Certainly, the factory fodder could be dismantled and tweaked a bit, but this would primarily be with regard to propellant charge and selection of the most uniform bullets and cases. The ability to select from an assortment of quality bullets would be a real advantage in working up accurate loads for the new rifle. I considered the possibility of swaging down .224 diameter bullets to 5,45 caliber, or basing the rifle on an AKM and using the .220 Russian cartridge, but I wanted to keep the job of handloading as simple as possible.

So, I called Dave Manson ( Dave Manson Precision Reamers, 8200 Embury Road, Grand Blanc, MI. Ph: (810) 953-0732, Fax: (810) 953-0735), and asked him to grind a special reamer for me. The chamber that this reamer would cut would be for the “.220 Parker”, and this cartridge would be the quick-and-easy way to solve the projectile dilemma. Now, the .220 Parker is nothing more than a 5,45x39mm Soviet cartridge that uses a .224 diameter bullet - essentially a “5,56x39mm”. While still a wildcat in the strictest sense of the definition (a cartridge for which no commercial ammunition is loaded), there is certainly nothing spectacular about this round. It doesn’t “bridge a gap” between existing cartridges, and it doesn’t offer any velocity advantages over anything currently available. What it did offer was the ability to choose a good quality .224 caliber blank to machine the barrel from, and then select from a vast assortment of good bullets. Best of all, John wouldn’t need any special tools to assemble his cartridges. Readily available Russian ammunition would furnish primed cases after pulling the bullets, and for about 10 cents apiece. While these cases probably aren’t what you’d call “match-grade”, the ones I’ve inspected seemed uniform enough to serve the purpose. As a bonus, if John wanted to get really thrifty, he could probably even find a use for the salvaged Russian propellant.

To seat the new bullets, I had Dave Davidson out at C-H/4-D Tool & Die furnish a modified 5,45x39 seat die, in which the neck diameter of the die was honed up a tad. In hindsight, this was probably overkill. There’d certainly be no need to crimp these bullets in place, so alternate methods could have been used to seat the .224 projectile - eliminating the need for custom dies altogether. Minimally, a bullet puller, simple seating tool, and shell holder would be all the tools required for loading the .220 Parker.

After I settled on the cartridge, John procured an ITM Arms AK-74 receiver from Ohio Ordnance, and construction of the rifle began. The front and rear receiver trunnions came from a Bulgarian AK-74 “parts kit”. Rather than riveting the trunnions in place (as is standard practice) I prefer to install these in the receiver shell using machine screws. The process involves boring the existing rivet holes in the trunnions oversize, press fitting filler plugs into the holes, TIG welding them in place, and then machining the welds flush. The trunnions are then fixtured to the receiver shell at the proper location, tapped holes added at assembly, and ten modified button-head screws hold everything together. Finally, I fill and finish the socket heads of these screws to replicate the appearance of the original button-head rivets. The whole process involves more work than simply riveting the trunnions to the sheet metal shell, but I think my method produces a receiver that’s a bit more uniform.

While other Bulgarian parts were used in the rifle’s construction, it can be seen from the photos that many custom made components were employed. As mentioned previously, there’s hardly any accuracy-enhancing “add-ons” available from aftermarket sources for the Kalashnikov - probably because the bazillions of semi-auto AK’s in this country are primarily used as plinkers. Consequently, I had to design and fabricate most of the “goodies” seen on this rifle from scratch. An original AK-74 front sight was cannibalized for it’s sight post and the threaded portion that accepts the muzzle brake. The tangent rear sight and its base was also removed from an AK-74 barrel, to be reworked into the new rear sight assembly. A Bulgarian bolt and bolt carrier was fitted, as well as receiver cover, return spring assembly, selector lever, and trigger guard/magazine catch. I also modified a stock gas tube to fit the rifle, but after that it was mostly time spent in the machine shop that provided the balance of the components.

The heart of any rifle is the barrel of course, and the one that I employed required a little thought. First and foremost, I wanted to dampen the effect that the “slam-bang” Kalashnikov operating system has on accuracy, so I calculated for the heaviest possible tube that could be stuffed into an AK. I determined that a barrel with an outside diameter of 7/8” would be about maximum. Since the standard AK-74 has a barrel diameter of only .575”, it took a bit of work to make the heavy barrel fit. A Douglas XX Premium chrome-moly blank in .224 caliber was selected, with a 1-8” twist. Some folks will sneer at anything but a cut-rifled tube, but I’ve obtained very good accuracy from these barrels in the past. After turning the blank to the .875” outside diameter, I cut it to 19” overall and machined the shank for a press fit in the receiver trunnion. It was then chambered, the muzzle given a recessed crown, and during installation it was headspaced on a Manson go-gage.

With the bull barrel on the receiver, all of the barrel mounted components naturally had to be modified or made up from scratch. The standard Kalashnikov rear sight base had to be substantially modified to fit the massive barrel. The existing barrel band was removed from the sight base, and a new band was fabricated for it. These components were machined to provide the correct height for the sight base, then fixtured together and TIG welded. I modified the sight leaf by eliminating the “U” notch, and sweated on a simple aperture.

Next, I had to design and fabricate a gas block that would not only fit the .300” oversize barrel, but still work with a stock gas tube and handguard. A U.S. made hardwood forend and it’s retaining ferrule had to also undergo rework to be made to fit. The new front sight assembly was also made up from scratch. It uses the stock AK post, with elevation zero via its 0.75mm thread. Windage zero is via a screw adjustable dovetail, similar to that used on the FN-FAL’s rear sight. A steel globe was machined and fitted to protect the post, and the finished unit clamps to the barrel via two socket head cap screws.

Even though they’re an improvement over those on a stock AK, these iron sights naturally weren’t going to allow the full accuracy potential of the rifle to be realized. After examining what was on the market for AK scope mounts, I didn’t find anything that I particularly cared for. Most either lacked the rigidity I wanted, were of sub-standard material or quality, or they didn’t place the scope directly over the axis of the bore. So, I designed and built the swept-back steel mount that you see here. The base was roughly styled after the “optics plate” found on the AK-74N, but I incorporated a rectangular rib rather than a dovetail. The detachable mount was machined from a hunk of 5/16” thick steel angle, with a groove machined to provide a light press fit on the rib of the tool steel base. The mount secures to the base with two large knurled-head machine screws, and it consistently returns to zero when removed and replaced. On top of the mount, I located a Picatinny rail exactly over the bore’s centerline, and secured it from below with three large flat head machine screws.

As John hadn’t yet decided on a scope for the rifle, fabricating the mount at this point was sort of “putting the cart before the horse”. I wanted the scope to be mounted as low as possible, but I also had to be prepared in case John showed up with a scope that had a behemoth objective. Eventually, he brought over a Nikon Monarch UCC 6.5-20 x 50mm, which I mounted in Warne “Maxima” rings and still had plenty of room to spare. It was apparent that the dimensions of the standard AKM buttstock wouldn’t allow a consistent, repeatable cheek weld when using a scope and, since the stock also had be useable with the iron sights (which are the same height above the bore axis as those on a stock AK), I decided to modify the buttstock to incorporate an adjustable comb. It can be adjusted for height as well as cast, and I machined sets of spacers that provide two pre-determined heights - for either iron sight or scope use. To enhance ergonomics in a variety of different shooting positions, I decided that the buttplate would need to be adjustable as well. Since none of the adjustable buttplate systems available were compatible with the relatively small buttstock, I designed and built one that incorporates a Pachmayr Decelerator pad. It adjusts for height by simply loosening its clamp screw, positioning the pad to the desired height, and tightening the screw. Providing adjustment in .050” increments, the grooves on the meshing faces of the buttplate were made with a checkering file. (When I worked for Austin Behlert back in the 80’s, I sometimes hand-checkered nearly a dozen 1911 frontstraps in a single week - and my fingers are glad those days are over!). The buttpad assembly also increases the rifle’s length of pull to 14”, which alone makes it a lot more comfortable.

For compliance with federal regulations, the muzzle brake is attached to the barrel via a sleeve that is held to the muzzle by four set screws. The sleeve incorporates the threaded portion from the original AK-74 front sight, and the brake locks in place on the threads via a spring loaded detent. It can be removed for cleaning, or to attach other brakes that use the same thread. The AK-74 brake is well known as a potent recoil reducer, albeit at the cost of increased flash signature and side blast. When used on a heavy barreled small caliber gas-operated rifle, the need for incorporating this brake might be considered questionable by some. However, since I wanted to remove as much recoil as possible from the system, I even went further - I also installed a Breako mercury recoil reducer in the buttstock for good measure. The combined effect of the enhanced ergonomics and these recoil reducing features worked out quite well - felt recoil is about what you’d expect from a spring/piston air rifle. I also machined a mounting block to attach a Harris S-L Bipod to the barrel. The front sight, muzzle sleeve, and bipod mount were all machined from 6061 aluminum. Regular 30-shot AK-74 mags proved to be a bit long for the short S-L bipod, but East German “red plastic” mags are easily shortened (besides being dirt cheap!). The shortened mag shown here holds 15 rounds.

The trigger used is the previously mentioned Power Custom/Red Star unit. An excellent design, it’s adjustable for sear engagement, weight of pull and overtravel. It can also be set up to provide either a single or two-stage pull. At John’s request, it was adjusted for a military two-stage pull, a weight of 2 pounds, and zero overtravel.

When it came time to assemble some loads for testing the rifle, I noticed that there wasn’t much in the way of .224 diameter bullets on my loading bench. The only projectiles I had on hand were some Hornady 68gr. BTHP match and a big Planter’s peanut can of pulled surplus 56gr. ball (both left over from my wife’s brief fling with a Colt HBAR). So, I figured I’d start with these and, if I couldn’t obtain decent accuracy, I’d then order some different bullets. I pulled the 60gr. bullets from berdan primed Wolf 5,45x39mm ammunition to obtain primed cases and, for initial function testing, I simply seated a few of the 56gr. pills on top of the factory propellant charge. These loads cycled flawlessly through the rifle, but only produced “plinker-grade”accuracy. Next, I seated the Hornady bullets over 22.5grs. of 4895, the charge filling the cases to about halfway up the neck. It was colder than blazes when I tested these, so I didn’t bother to set up the chronograph. I imagine they were traveling around 2300 fps.

With the scope set on 20x, I could see that the bitter cold was producing considerable shiver-induced tremble. My best 5-shot groups at 100 yards were barely within 1.5”. I was telling myself that this definitely wasn’t a good day for an accuracy test, as I was on the verge of frostbite. But since I went through all the trouble to get set up and still had some ammo left, I hunkered down for one last try. Maybe it was because I was nearly frozen solid, but I finally managed to print a group measuring .675”! Man, that was good enough for me - I was back to the shop and in front of the pellet stove so fast that I couldn’t remember how I got there.

Obviously the rifle is capable of holding it’s own against an AR-15, and that was the whole point of building it. It’s the kind of thing that materializes when gun cranks get together to shoot the breeze and before long cook up some crazy idea - it happens all the time here. Sure, it would have been a lot more practical to just put together an AR, but what fun would that be? John has already laid in a supply of Russian 5,45 ammo to provide cases for the rifle, and I know he’ll be assembling various loads to experiment with at the first hint of warm weather. One thing is certain - as long as shooters keep dreaming, guys like me will never run out of work!

Caliber: .220 Parker (Soviet 5,45x39mm w/.224” projectile)

Operation: Gas, semi-automatic.

Barrel: Douglas XX Premium, chrome-molybdenum steel, button-rifled 4 groove R.H.

twist 1-8”

Barrel Length: 19”

Overall Length: 41.5”

Weight, empty: 10.0 lbs.

Sights: Front: custom made protected post, adjustable for windage and elevation zero.

Rear: Sliding tangent-type w/ 230” diameter aperture, adjustable for elevation

100-1000 meters with 500 meter battle sight setting. Custom made detachable steel

Picatinny rail side mount with Nikon Monarch UCC 6.5-20 x 50mm telescope.

Feed: Custom 15-shot detachable box magazine, also uses 30-shot AK-74 box magazines.

Finish: Parker “Ultra-Kote”, Mil-Spec thermo-bonding black polymer.

Stock: Modified U.S.-made hardwood AKM forend and handguard, buttstock

incorporates height adjustable buttpad, cheek rest adjustable for height and

cast, U.S.-made plastic pistol grip.

Status: Custom, non-production.

Price: Not for the faint-of-heart.



SLIDE CAPTIONS:



1) Right side view of Parker’s heavy barrel Kalashnikov.

2) The rifle incorporates a steel Picatinny rail side mount, Nikon Monarch UCC 6.5-20x

scope, and adjustable cheek rest and buttpad.

3) The custom Kalashnikov shown with a stock Bulgarian AK-74 in

5,45x39mm for comparison.

4) The 7/8” diameter bull barrel, heavy gas block, Harris SL bipod and mounting block,

custom front sight, and muzzle brake.

5) Stock AK-74 semi auto, showing the comparatively light .575” diameter barrel.

6) The massive steel scope mount provides a consistent return to zero, while the

adjustable cheek rest allows a repeatable cheek weld with either scope or iron

sights.

7) Combined with the heavy barrel and mercury recoil reducer, the AK-74 muzzle brake

all but eliminates recoil.

8) The rear sight, converted from “U”-notch to aperture, can be seen under the scope.

9) The “business end” of Parker’s accurized Kalashnikov rifle.

10) The buttstock features a custom made cheek rest and buttpad, both fully adjustable.

11) (photograph) Best group shown with three Soviet cartridges (l. to r.): 7,62x39,

5,45x39, and .220 Parker (5,56x39) loaded with 68gr. projectile.

Posted Image
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http://www.sniperspa...mag/aug2004.htm

http://www.shooting-...ice_book_29.htm
  • GunnyR, therisensun, mav and 1 other like this

#2 Fluid Power

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Posted 15 January 2010 - 12:58 AM

Great story! Loved it. Now that gets the juices flowing!

Interesting that the pulled 5.56 bullets using stock powder loads were not so good. Hell, I've seen posts groups almost as good from Aksarben using the .223!

Thanks,

Frosty

Edited by Fluid Power, 15 January 2010 - 12:59 AM.


#3 GunnyR

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Posted 15 January 2010 - 11:12 AM

Thanks for posting this!
GunnyR

Hey NJ, Got Defense?
NJCSD

#4 JK-47

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Posted 16 January 2010 - 12:25 AM

I think a shorter gas system might help accurize the AK.
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#5 post-apocalyptic

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Posted 16 January 2010 - 01:12 AM

I think a shorter gas system might help accurize the AK.


Perhaps. However, a shorter gas system would likely detract from the AK's legendary reliability. Regardless, the AK as-designed does the job it was built to do very, very well.

This article is an excellent read, though. :up:

Edited by post-apocalyptic, 16 January 2010 - 01:13 AM.

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#6 Apache

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Posted 16 January 2010 - 01:51 AM

Stories like this really make me wish I had a machine shop at my disposal, but then again if I did I'd probably never leave it, LOL. A few years ago a guy heavy barreled a SA M-5 and was getting great accuracy with it ...
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#7 bigsal

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Posted 16 January 2010 - 01:56 AM

Its interesting that this guy is attempting to accurize his 74. I had the same issues last week when It hit me: why not use rendered fat to improve performance? After several hours in the shed, I rubbed my 74 in bacon grease and had a buddy hold a penny a mile down range. On my command he released the penny 13.648 feet in the air. Using my grease-modified rifle, I was able to not only hit the penny mid flight, but also a second penny that happened to be in the air floating behind the first. I was so happy I decided to remove the tires from my car. Here is a pic:
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#8 G O B

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Posted 16 January 2010 - 08:39 AM

The biggest accuracy problem is the AMMO!
A bull barrel, a gasblock with an adjustable chamber volume (to allow the bullet to exit the barrel before the action begins cycling), and GOOD AMMO --- and an AK will be a accurate rifle.

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