The AR has the gas rings and pressure behind the bolt because it has a lot of lug area, and the lugs are flat with no cam angle. To get it to unlock while there's still adequate pressure available, the gas into the AR bolt briefly reduces the load on the lugs.
The AK also has a flat lug bearing surface, but much smaller in area than the AR, and the flats radius down into opening cams on the lugs. You don't have to force the AK bolt completely out of alignment with the trunnion; you just have to kick if off the flat spot and it'll open itself.
By comparison, my Ross bolt-action rifle has no flat spots at all - the receiver and bolt head are both machined at a shallow angle. It doesn't blow open during firing because the friction from the lugs mating is enough to keep the bolt from opening, sort of like the friction of your tires keeps your car from sliding down a hill if you park on an incline. (unless you live in Virginia, where any lot with less than an 80 degree slope is considered "flat") The point where friction is overcome by load is called the "angle of repose".
The Ross is designed that way to make the bolt easier to open, because it uses a straight-pull design that has poor primary extraction leverage. And though it's not relevant to the concept of a direct impingement AK, I spent hours staring at bits of that rifle laid out on my desk wondering "WTF?" and wanted to share it with someone...
00056 BARREL, AMMO, AND A TIGHT BOLT, WILL MAKE THE GUN SHOOT ACCURATE, ADD A TRIGGER AND OPTIC RIAL THAT IS SEPERATE FROM THE RECIVER AND THAT WILL ALLOW YOU TO SHOT IT ACCURATE.
GETTING THE LAST LITTLE BIT IS WHAT MAKE A GUN SUPER ACCURTE vs JUST ACCURATE.
iM NOT SURE ANY OPERATING SYSTEM IS GOING TO SHOW MUCH AS FAR AS ACCURACY GAINS EXCEPT IN HOW IT AFFECTS BARREL HARMONICS EITHER FROM IT TOUCHING THE BARREL OR HOW ITS WEIGHT AFFECT IT. tHE BULLET IS LONG GONE BEFORE THE ACTION MOVES SO I DONT SEE MUCH TO BE GAINED.
HOW DO THE PISTON CONVERTED AR,S COMPARE TO THE STOCK ONES AS FAR AS ACCURACY WITH THE SAME QUALITY BARREL???????
Last edited by 1biggun; 06-04-2015 at 07:58 PM.
I fear we're just arguing semantics though. A while ago you said stoner gas impingement, rather than just normal impingement like you're talking about in this recent post.
A list of things put together from various sources, fellow AK geeks, and from personal experience to upgrade an inexpensive WASR. Suggestions welcome:
* Test mag well to ensure polymer mags fit; steel mags usually fit OK with polys being snug or even too big. Dremmel mag well and/or fit poly mags.
* Check front sight base and gas block and correct with vise and rubber hammer, as required. Remove and repin if needed.
* Replace trigger group with G2 or RSA adjustable kit. Fit as required for smooth operation but with hammer block and safety working properly.
* Replace fire control group shepherds crook with retaining plate.
* Replace welded piston with a properly pinned unit if you’re concerned about the CAI method.
* Replace Warsaw Pact length stock with Kvar NATO lenth if you like a longer LOP. Pair with Magpul AFG or stubby vertical grip if you use a 'wrap-around' hold.
* Replace Com Bloc pistol grip with ergonomic grip that fits you best. Tapco SAW, US Palm, Mako, etc.
* Pull the safety lever away from the receiver far enough to ensure easy actuation, smooth inside as required.
* Dehorning and smoothing rough edges everywhere on mating surfaces, being careful on trigger components.
* Cut a wider slot into the rear sight, ensuring it stays centered, to speed up acquisition time. Blacken, reblue, or paint the exposed metal so there’s no shine (or rust).
* Bench test with all commonly available ammo, from a shooting rest and using a good optic. Test with brake, forearm, and cleaning rod removed. Allow time to cool between shots.
* Repeat bench tests with the selected ammo trying different forearm styles and fits (loose or tight). Note how accuracy is affected and select a forearm that works for you and doesn't affect accuracy.
* Repeat bench tests using tight and loose gas tubes. Find out how your baseline mechanical accuracy changes with loose or tight tubes.
* Repeat bench tests with different muzzle brakes. Note how accuracy is affected and select a brake that works best for you and doesn't negatively affect accuracy and POI.
* Repeat bench tests with and without the cleaning rod attached and decide whether or not to install it on the rifle.
* Ensure the receiver cover is not pushing against the front trunion when installed. Grind enough material off the front edge for a better fit if it is pushing against the trunion.
* Benching the weapon again every time something is added, such as a light, new rail system, heavier scope, etc.
* If you're not handloading, try weighing and measuring the surplus ammo for sorting. We do it for long range shooting, why not an AK when you need all you can wring out of it for a competition.
* Spare Parts: firing pin, 2032 batteries.
use better ammo helps the most.
THis is my groups using a Milled Hungarian AK-55 reweld by Turbothis and at 77 yards using Lapua Match ammo.
also I noticed that the Ultimak has seemed to fix and tightened all of my rifles groups considerably. David Fortier stated this phenomenon when he tested the Ultimak out and has stated the same thing years later.
I suspect the ultimak set up braces the barrel. I have a AMD pistol that will shoot 1" groups and the gas block is on there super tight because i welded a scope rail to it. My therry is it acts like a strut that you see the mini 14 guys use.
Id like to try some of that lapua ammo or at least the brass.
00057 I have reloaded with about every thing and the 150 grain 310 stuff seems to be the way to go for me. I have played with the .310 V max from hornady and there pretty good I honestly have not had time to do much lately. I dont get to carried a way with factroy barrels any more other than getting hunting accuracy ( 1.25" at 100) after that it good to go. the round is getting weak at 200 yards so if i can shoot 3" a that range or so im calling it good. i have spent considerable time with .308 barrels and match grade bullets and its not hard to get under 1" with a heavy barrel 308x39. getting under 1/2" is tough but i have done it from time to time. that when brass quality and all the 5% stuff starts to matter.
I have shot one hole before with 4 shots and had a 5th touching the group but its not every time.
You also got to factor in how good a shot you really are. Im not pro or anything there are a lot of guys better than me. My eyes are not what they were. most guys can shoot 3/4' groups with a good varmint rifle if its accurate not every one can do better than that.
I have been talking to a guy who competes on a national level and he is willing to do some trigger work at some point. It will be interesting to see how much better he can do if any. he has been trying to get me to enter a few matches just for fun but i seldom have a day to spend doing that. Id like to get some input from him on my trigger work as well as anythig else he can tell me. he builds some pretty competive bolt actions so Im hoping this will all gel. I met him at a range one day and suprised him with how well my AK pistol shot and really got hin interested when I pulled out the varmint 223 Ak.
Last edited by 1biggun; 06-04-2015 at 07:58 PM.
The concept of an accurate AK is both ludicrous and supremely enticing.
I have played around with this concept off and on for years now. Here is my collective experience for all to consider.....
I started out playing around with Norinco SKS rifles back when they could be had for $60 brand new. Using my relatively new experience with Mausers and Enfields, I used 7.65 Mauser barrels as a starting point. I quickly abandoned this direction and went to .308 blanks. It is amazing just how accurate the Brown Lacquer "RPK" chinese ammo can be out of an SKS like that.
I then moved on to commonly available AK's....Like SAR-1's, MAK90, MAK-91....
I had little luck with anything that had a 1mm stamped receiver. Those just tended to flex too much. Norinco MAK90's had a 1.6mm receiver, and they did a lot better. The best results I had were from NMH91s...Milled. Those rifles, with a well made barrel did very well, and were excellent when coupled with handloads using hunting grade .308 projectiles.
I have also tried things like stiffening plates on the outside of the receiver, rail work, and even a custom machine bolt carrier. Just to cover the bases, yes, blueprinting, yes custom throating, yes, yes, yes, yes.
Since I am ADD....I also played around with FALs at the same time. Century L1A1s could be had for $225 in those days. This was the reason why I abandoned AKs for accuracy. Why bother with an AK that was underpowered, when I could use an L1A1 as a donor for about the same price?
I was still occasionally intrigued by the thought of an accurate AK. But I never came up with anything that would affect the result beyond what I had already done. Simply put, 3/4 MOA from an AK at 100 Meters was pretty impressive. That is the best I ever did. And it was NOT repeatable....FALs on the other hand could hit that mark with regular repeatability. Keep in mind that there is a big difference between 100 Meters and 700 Meters; and a HUGE difference between a cold-bore five round string and blasting away....Precision rifles are not shot that much, by comparison with your standard $300 AK, or $150 SKS.
I read Will's (Red Jacket Firearms - Son's of Guns) write-up on his take of the Accurate AK, and I have to say that I think he nailed what is possible with this platform. Keep in mind that he started out with a Saiga .308, then strengthened the receiver / trunnion interlock with a wrap-around "sleeve" that locks that whole assembly together. The starting point on his barrel was "pricey" to say the least. Oh, to be Will....
Here is my conclusion:
You can make any rifle shoot well. There are a lot of examples of very accurate AK rifles out there. AKs do have some weaknesses in this regard, so selection of an appropriate donor rifle is as important as any other factor. Lastly, even the best rifle in the world can be negatively affected by the ammo used. You want pin-prick accuracy, you are going to have to use / make / procure match grade ammo. It is as simple as all of that.
Imagine whirled peas
Peace, Love, And Superior Firepower
00058 ITS NOT HARD TO GET 1" GROUPS WITH A THIGHTER CHAMBER THAN THE STANDARD AK HAS. SOME OF THOSE CHAMBERS ARE REALLY SLOPPY. AS MUCH AS .015 SIDE CLEARANCE. IF YOU WERE TO FIRE FORM BRASS TO FIT THE CHAMBER YOU COULD LIKELY TIGHTEN UP THE GROUPS CONSIDERABLY, HOW EVER THE GUN LIELY WOULD NOT BE VERY RELIABLE.
I REPEATE AGAIN mY VARMIONT RIG USES A BNET TAPCO BLANK WITH ONLY THE HOLES AND LOWER RAILS HARDENED. I DID DO SOME SUFF TO TIGHTEN UP THE PLAY BY CUSTOM FITTING THE RAILS AND HAVING THEM TAPER SO IT LOCKS UP TIGHTER, BUT THE TRUTH IS THE GUN HAS SHOT NUMERIOUS DIME SIZE GROUPS AT 100 YDS WITH A $12 HOME MADE RECIVER. GET THE SCOPE OFF THE RECIVER AND YOU ARE GOING TO SHOOT BETTER. i CAN LITTERALY TWIST MY GUN AND YET IT ALWAYS SHOOTS GOOD AND HOLDS A ZERO.
I HAVE NEVER SHOT UNDER 1.25" ( 5 @ 100 YDS) WITH ANY SIDE MOUNT OR DUST COVER MOUNT OPTICS. I HAVE SHOT UNDER 1" WITH A CANTALEVER MOUNT ON SEVERL DIFFERANT RIFLES AND 1" WITH A GAS TUBE MOUNT ON A 14" PISTOL.
YOUR KIND OF SOL WITH A FACTORY STOCK aK OTHER THAN THE BIG THREE TRIGGER, AMMO, OPTICS AND YOU NEED THE OPTICS OFF THE RECIVER IMOO.
I NEED TO BUILD UP A RIFLE WITH BOTH A SIDE MOUNT AND A CANTERLEAVER TYPE MOUNT LIKE I NORMALY USE AND DO BACK TO BACK TESTING TO BE ABLE TO DOCUMENT A DIFFERANCE.
Last edited by 1biggun; 06-04-2015 at 07:59 PM.