Today I am joined by Forgotten Weapons Field Research Assistant Clay to test out one of those super-extended 90-round AK mags that are so often seen at the junk tables of gun shows. How bad are they? Or do they actually work? Let’s find out…
Arkady Shipunov and the GSh-18 Pistol
Book Review: The Kalashnikov Encyclopaedia by Drs. Cor Roodhorst
All three volumes available worldwide from: http://www.kalashnikov-encyclopaedia.com While there are several books available which showcase a decent number of different Kalashnikov variants (like Tokoi’s work), and there are good reference works on the history and […]
Never try this at home, kids! “Linear equation y=a*x+b type logic” fails in this case! By linear equation logic, I refer to the usual perception that every real-life system behaves in a linear manner. A good example of incorrectly applying algebra to life is the usual “idiot’s attempt to quickly cook a turkey by turning up the oven temperature to twice that specified in the recipe so that the turkey will supposedly be cooked in half the specified waiting period.” Doing this will burn the outside of the turkey to a crisp and leave the insides cold if you check the turkey at the supposed “speedy-well-done” time. In a similar manner, if a particular braking distance is required to safely stop a car driving at a particular speed, 4 times (not twice as believed) that braking distance is required to stop the same car going at twice the original driving speed!
Increasing magazine capacity is not a matter of just making the magazine longer and getting a stronger spring. One must account for cartridge geometry, the forces of the follower spring and bolt upon the cartridges during shooting, and overall stress reactions. Just as a rifle is considered a system of parts, a magazine must also be considered a system of parts that must work together properly in order to feed ammunition without catastrophic malfunction. Compared to the 90-round chop-and-weld monster of a magazine, the proper drum magazine given to the Luger and the later MP-18 was very well thought out. I’m very sure Daweo can clue us in on how to properly make (or not make) a high capacity magazine for the AK and the RPK.
Did I miss anything or mess up?
You equation applies exactly as written. I would write is as y = k.x+q where “k” is spring constant and “q” is preload; result will be the same.
Well, you’re right about the spring compression force being exerted on the follower spring by the cartridges and feed lips (normal force). The problem is that the floor-plate to which the spring was attached in the magazine wasn’t an ideal reference point throughout the entire video. And if y=k*x+q, then how do we define the x-axis for the magazine, given it is NOT totally rectilinear?
It is little bit of simplification, I am aware. Also, calculating rectangular profile spring in not as easy; stacking up two springs doubles displacement but load is the same; you need new spring. Welding one on top of other will make changes in temper; local weakening.
Typically people tend to experiment and see what works as best. The floor plate by itself is not enough, it also needs locating plate with cut-out into which floor plate latches. When you do whole new mag design you have field open, but as you build on something existing you are stuck with what you have – it is more difficult to optimise that way.
One more item of interest: I always lean towards not going into almost solid stack – it is a bugger. It is much better to leave some space in nominally full mag and to extend follower leg (if not present add it) so that some ‘smartie’ does not load an extra round or two, which would kill your intent. Better two rounds less than one more which can cause stoppage.
Makes sense to me.
” Daweo can clue us in on how to properly make (or not make) a high capacity magazine for the AK”
See post from 02-02-2005 12:44, 6th image from top here:
Top: 90-round pan magazine (RPK-74)
Middle: 60-round magazine (AKM)
Low: 100-round magazine, 7,62×39
Neither worked good enough to be adopted.
For comparison see 1st image from top from that post (from RU patent 2158890), it is how 60-round magazine for AK-74 works, notice despite being multi-column it has one common spring.
Graphical comparison of various less-common magazines for AK family:
1st from top: 10-round banana, used in Bulgarian weapons for grenade-launched (blank cartridges)
2nd from top: 40-round banana
3rd from top: 50-round banana
4th from top: 60-round 4-column banana
5th from top: 75-round banana
6th and 7th from top: 100-round banana
8th from top: 100-round pan
AK family magazines overview (Russian language): http://patr1ot.no-ip.org/mag
Excellent source, thank you. Yeah, mag design is a trade on its own, for sure and, as it was said couple of times, it is a key to reliable weapon. In that chat is also mentioned Spectre; that thing works well afaik. Some AK mags with 4 to 2 also worked I believe.
Going into reading is enticing – but I will likely suffer hyper-extension from reading in Russian again 🙂
There was also тема «Поплин», which resulted in ПУ-21, which can accept belt or magazine
Carry On Kalashnikov made me laugh out very loud.
Can you test those new RPK-16 96-round 5,45x39mm drums one day?
When he said he expected the floor plate to fly off, I didn’t get it. Then the floor plate flew off, and the problem was obvious. Thank you for this, and Merry Christmas.
You got further than I did the time I tried a cheap 30 round magazine for an HP-35. When I tried loading it at the range I got to round 28 and the floor plate flew off, followed by the spring, follower and 28 rounds, all bouncing around on the concrete. 🙂
Argh! Autofill put the wrong name. It’s supposed to be Stickmaker. *Headdesk*
I offer here the thoughts from the great firearms philosopher IVAN CHESNOKOV, in this case a discourse on a different variant from the original AK design (adding a rail):
IVAN CHESNOKOV !!4AFNigi37A 06/10/10 (Thu) 22:32 No. 6338938
WHY YOU WANT RAIL FOR KALASHNIKOV? IS NOT GOOD ENOUGH AS PROCURED FROM IZHEVSK MECHANICAL WORKS? YOU THINK NEEDS IMPROVEMENT? THEN MAYBE YOU FIND JOB WITH ARMY OF RUSSIA! YOU HAVE DRINKS WITH MIKHAIL KALASHNIKOV, TRADE STORY OF MANY WEAPONS DESIGNED AND DETAILS OF SCHOOL FOR ENGINEERING!
OR MAYBE YOU NOT DO THIS. PROBABLY IS BECAUSE YOU NEVER DESIGN WEAPON IN WHOLE LIFE. YOU LOOK AT FINE RUSSIAN RIFLE, THINK IT NEED CRAZY SHIT STICK ON ALL SIDES OF WEAPON. YOU HAVE DISEASE OF AMERICAN CAPITALIST, CHANGE THING THAT IS FINE FOR NO REASON EXCEPT TO LOOK DIFFERENT FROM COMRADE. YOU PUT CHEAP FLASHLIGHT OF CHINESE SLAVE FACTORY ON ONE SIDE, YOU PUT BAD SCOPE OF AMERICAN MIDDLE WEST ON OTHER SIDE, YOU PUT FRONT PISTOL GRIP ON BOTTOM SO YOU ARE LIKE AMERICAN MOVIE GUY JOHN RAMBO. MAYBE YOU PUT SEX DILDO ON TOP TO FUCK YOURSELF IN ASSHOLE FOR MAKING SHAMEFUL TRAVESTY OF RIFLE OF MIKHAIL KALASHNIKOV, NO?
RIFLE IS FINE. YOU FUCK IT, IT ONLY GET HEAVY AND YOU STILL NO HIT LARGEST SIDE OF BARN. GO TO FIRING RANGE, PRACTICE WITH MANY MAGAZINE OF CARTRIDGE. THEN YOU NOT NEED DUMB SHIT PUT ON SIDE OF RIFLE.
Whoaaa…. this is funny. Attempt was well meant and by expectation it did not come out. This brings back memory of Ian’s discussion with Mr. Sullivan, author of Beta-Cmag. To create large capacity magazine in not an easy task. Even something like 30rd is a challenge. First you need lots of force to push the stack up which also acts as brake for action, at the end you may not have enough of it. I know something of that from my experience since I was involved with it.
Matisse Enzer I laughed enough for tears to come out, This thread is actually funnier than most Carry On films, apart from maybe Carry On Screaming, Carry on Cleo, and Carry On Cowboy (which also has guns).
IS GOOD YES?
Does the Comedy Channel know about this?
Reminds me of the time I was recovering from a tweaked motorcycle ankle injury and a friend was like recovering from a damaged Cosby slip-fall into a toilet. He shows up in my store on crutches, asks for “the crip dude.” Tondeleyo doesen’t even look up from from her knock-off “EyePadAroo,”. Just points her stylus at the crip which turns out to be me.
Hobble, hobble on my micro-used crutches over there and Dimitri (he’s really from Quintana Roo, but thought “Dimitri” sounded more exotic) sez, “Using my legendary powers of negotiating powers, I have booked us on the “Comedy Channel.”
“Are you free next month for the “One Legged Men Ass Kicking Contest?”
“Even something like 30rd is a challenge. First you need lots of force to push the stack up which also acts as brake for action, at the end you may not have enough of i”
Or go Lewis-way and make drum magazine propelled by weapon itself – Lewis LMG.
Slight correction: the Lewis gun uses a pan magazine, not a drum. But yes, we can avoid the problems of magazine followers if we use a feed indexing mechanism operated primarily by the bolt. The American 180 uses a pan magazine that requires a winding key because the bolt of that gun doesn’t carry enough momentum to index the pan. Other methods of feed that won’t require springs for primary indexing include belt-feed, strip-feed, and hopper-feed. Did I mess up?
Yes, should be pan magazine, which seems to be best choice if you want really high capacity and not belt-fed. It can work with rimmed magazine (MGV-176) and with rimless (Reibel tank machine gun), could be “tweaked” in terms of diameter and thickness (adding layers of cartridge, compare DP 47-round big-diameter-single-floor with DT 63-round small-diameter-triple-floor magazine) unlike drum which could be done in various diameter version (cf. Thompson sub-machine gun) but not in thickness.
Armée de l’air in 1930s well-liked pan magazine, for example for MAC 1934 machine gun existed 500-round pan magazine – in such variant it was used as pursuit aeroplanes fixed mg, magazine was propelled by pneumatic system (see drawing in link)
Pan magazine was also used in MAC 1938 machine gun, firing 11×78 cartridge, capacity was 250
I also like pan mags – they work, although look little awkward. Russian grunts used them as shields 🙂
75-round magazine was also used in 2Б-П-40 by Konstantinov, see 2nd photo from top:
(it was one of entries of competition which will eventually led to RPK)
The mass of the rounds to be started and stopped to get one single round in the chamber creates forces that act negatively on the cycling bolt and magazine latch in the receiver.
Just too heavy to move them all that fast.