Author Topic: My AK blew up (Read 2487 times)

TargetTerror · « **on:** February 28, 2008, 09:41:07 AM »

I took my first hand loads for my AK to the range last night. Suffice it to say, things didn't go as planned. I am fine, fortunately, though my ego has been hit down a notch or two. I fired about 5 rounds with no problem. POI was way off, but the rounds fired and cycled fine. They actually felt much lighter than the cheap Wolf ammo I normally feed my AK. On about the 6th round, the gun fired and the explosion seemed much closer in (though not appreciably more intense), the top cover blew off and some hot gas spurted out the top. The bolt was stuck, and took a few good whacks to pull the case head out. The rest of the cartridge remains in the chamber. Ironically, this shot had the best POI of any of the rounds I loaded

I loaded some old lead bullets I that I got on sale in brand new Winchester brass on top of 14.5 grains 2400, with Winchester LR primers. The lead bullets were sized to .311, were 150 grains, had gas checks, and other than having lube all over them, seemed decent enough. COL was ~ 2.060", give or take a bit.

The gun still seems to function and cycle fine, though I obviously haven't tried another round yet. I think the bolt is FUBARed. The firing pin flops around, which I'm pretty sure it didn't do before. The extractor also looks slightly bent, and there is a gap between it and the rest of the bolt face (red arrows in the pics). The top cover is bent, and I'll need a new one of those too.

It looks to me like the round fired out of battery. If you like at the picture of the case head with the red arrow, the arrow is pointing to a band just beyond the groove of the head. That looks to me like the cartridge was unsupported there. What do you guys think?

I have 2 theories about how that could have happened. I first thought that some of the excess lube got in the the chamber, and prevented the round from chambering fully. That did seem a little odd for only 5 rounds, plus the 5 I shot didn't have a lot of lube up on the bullet itself. My other theory is that the the bullet wasn't seated in far enough, such that the bullet actually hit the lands, preventing the round from seating fully. If you like at the photo of the rounds, the lead round is definitely thicker up at the top then the FMJ. I didn't want to seat the bullet much deeper for fear of raising the pressure. ~2" COL was what the manuals seemed to say for this bullet weight and type.

Anyone know a good place to get a new bolt and top cover? This is a Romanian, WASR, if that makes any difference. Also, it looks like I will need a broken case extractor. Who makes a good extractor for 7.62x39, and where is a good place to buy it? Does this look like something that I should have a gunsmith look at before shooting again? The barrel/chamber area seem ok. It just looks like the bolt that took the beating. (One question on the chamber: are the 2 cuts in the chamber face - the red arrows in my pic - supposed to be there like that?)

I was lucky I wasn't hurt, but this is a reminder to be careful!

Graybeard · « **Reply #1 on:** February 28, 2008, 09:53:39 AM »

While I profess no knowledge of AKs I believe they are gas operated are they not? Gas operated rifles and cast bullets do not play well together.

TargetTerror · « **Reply #2 on:** February 28, 2008, 10:02:48 AM »

Quote from: Graybeard on February 28, 2008, 09:53:39 AM

While I profess no knowledge of AKs I believe they are gas operated are they not? Gas operated rifles and cast bullets do not play well together.

I actually looked into that because I was hoping to load up some lead bullets for cheap plinking. General consensus seems to be that they should be OK, albeit with maybe a bit more cleaning.

In any event, I'm pretty sure that this failure is not due to the fact that the bullet I used is lead, specifically.

SHOOTALL · « **Reply #3 on:** February 28, 2008, 10:13:13 AM »

lead or no lead , what powder ? is that a good powder to use in a rifle ? ain't it somewhat fast ?
could you have double charged one ?

Dixie Dude · « **Reply #4 on:** February 28, 2008, 01:30:07 PM »

The AK, being gas operated and designed to shoot a 125 grain bullet, may not like the 150's you used. Could it be too much pressure build-up with the heavier loads. However, that said, one guy on the milsurp forum has reloaded 150's for his SKS to shoot hogs, and have a heavier load for deer. I believe his were cast lead also. The SKS may have a stronger action than the AK though. It is an older design and heavier.

billy_56081 · « **Reply #5 on:** February 28, 2008, 01:45:16 PM »

Will a double charge fit in thier? That case pic looks like it was exposed to a huge over pressure. But it could have been an out of battert fire also. The case does look similar to a 50 cal that fired out of battery in my M2 when i was in the army. The bolt on the M2 also broke in that case.

Foggy · « **Reply #6 on:** February 28, 2008, 01:47:44 PM »

As Bill said GAS OPERATED FIREARM DON"T WORK WELL WITH LEAD BULLETS. Lead also dose not mix with ported barrels. But I also think it's a powder issue
SKS are a better rifle then an AK. They ar stronger better constructed.
Foggy

TargetTerror · « **Reply #7 on:** February 29, 2008, 02:59:34 PM »

I talked to a local gunsmith, and I'm going to have him check it out and make sure everything is ok.

I also checked and yes, I could fit a double charge of 2400 in the case. But, that would have been a VERY compressed load, which I'd hope I'd have felt. The powder was may 1/3 or so of an inch away from the top with the double charge. Also, the bang when this round fired didn't see all that excessive - it just seemed like it came from the rear of the barrel instead of the front. I don't have any other experiences with such failures, but I'd think a severely overpressured round would sound VERY loud.

Thanks again, and keep the opinions coming, I'm curious!

Mikey · « **Reply #8 on:** March 01, 2008, 01:36:38 AM »

No, your detonation noise would have been less than with a normal round firing. Don't forget, when the case separated it did that as the bullet wqas about to leave the case, so you would have had two things happening at the same time - bullet leaving the case and case head separation - this is why the noise, and recoil seemed different.

Please also understand that in a gas operated rifle, heavier jacketed and heavier cast bullets do not perform the same. Your gas port will fill with lead shavings and the rifle will become a single shot and you will have to get that blind gas port cleaned out. Also, your bullet was heavier than normal and probably a bit oversized for the bore - all this would not have caused the case head separation which casued damage to the bolt and the bolt cover. You may well have overcharged your case without being aware of it or you may have used a piece of brass that was ready to separate with the next firing.

I have used 180 gn .311 diameter bullets over a low charge of WW296 for near or at subsonic levels in the AK without any problems. I would suspect an overcharge of powder. Mikey.

SHOOTALL · « **Reply #9 on:** March 01, 2008, 01:59:18 AM »

the other thing may have been a bolt that was not in battry . maybe when loading new cases one was a bit longer ?
did you trim ?

targshooter · « **Reply #10 on:** March 01, 2008, 04:49:55 AM »

IMO, this failure displays characteristics indicating you may have had a slamfire. The damage looks similar to that I saw in the service with slamfires in Garands and M14s. An overly sensitive primer or a raised primer can cause this.

jowl · « **Reply #11 on:** March 01, 2008, 04:51:46 AM »

check you cassins and clean your damn gun!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

S.S. · « **Reply #12 on:** March 07, 2008, 07:18:24 PM »

i have seen something similar to this. What I would suspect is that the failure started with the round previous
to the one that caused the damage. In the one i saw, the previous round had came apart at the shoulder
and had left the case neck in the chamber. When the next round fed in it of course didn't fully chamber before
slam-firing...... Boom!

SharonAnne · « **Reply #13 on:** May 01, 2008, 11:28:55 AM »

If the round loaded with the cast bullet is like the one that blew I know what happened. the round head spaced on the bullet and the case was not entirely chambered when it fired. You can tell by the way the case head expanded.

SharonAnne · « **Reply #14 on:** May 17, 2008, 04:20:16 PM »

BTW, I saw the same thing happen at a high power match. Shooter was using commercial loaded hunting ammo, 180gr round nose. M1A is NOT to be used with such bullets. Spitzers ONLY.

PA-Joe · « **Reply #15 on:** May 17, 2008, 04:34:36 PM »

Looking at the two rounds, the tip diameter of the lead round apprears to be much larger that the factory round. I would check to see if it was touching the lands (i.e. too long to chamber correctly).

SharonAnne · « **Reply #16 on:** May 18, 2008, 08:29:38 PM »

PA Joe. I do believe we said the same thing in different words

Mikey · « **Reply #17 on:** May 20, 2008, 01:34:54 AM »

SharonAnne: I suspect you are correct. There are a lot of cost slugs out there that could be used in the 7.62x39 but not all can be used in a semi-auto. Many will chamber fine in a bolt gun but the ogive of the bullet must be the same as that of the originally designed 123-5 gn bullet or the bullet may prevent proper chambering and set the stage for a slamfire. I agree with ya. Mikey.

demented · « **Reply #18 on:** June 03, 2008, 11:29:07 PM »

Be sure to check your headspace. We've found many Century built AK's with excessive headspace, they usually get by with this due to most shooters using steel cased cartridges. I have often wondered how long this problem would go unnoticed if more brass cases were used.

SharonAnne · « **Reply #19 on:** June 04, 2008, 09:38:27 AM »

Demented, scroll back to the top. Look at the round in question. I am pretty sure it was not excessive headspace.

DCRthe3rd · « **Reply #20 on:** June 04, 2008, 09:46:01 AM »

Quote from: SHOOTALL on March 01, 2008, 01:59:18 AM

the other thing may have been a bolt that was not in battry . maybe when loading new cases one was a bit longer ?
did you trim ?

\Yesterday as a matter of fact I discovered a wasr of mine that was firing but not always going into battery. Why? I don't know yet , how long has that been going on I don't know either. "who looks to see that the bolt is fully seated everytime?"
using wolf 124gr military classic , I noticed it on a very early round of a clean gun , so if it was dirt it would be left over dirt but I am anal about such things , luckly I didn't blow up or vaporize the gun , I found no cases that looked funny either , spent or otherwise

SHOOTALL · « **Reply #21 on:** June 04, 2008, 09:50:01 AM »

if by chance it steel cased ammo , check the chamber for the coating they put on the cases . When the chamber is hot it melts and coats the walls of the chamber . It is difficult to see sometimes and more so to clean .

DCRthe3rd · « **Reply #22 on:** June 04, 2008, 10:05:18 AM »

Yes that was a thought of mine , I would "like" to think I had removed any the previous time I cleaned it and I noticed it on round 3 of a "clean" gun so I don't think it came from that time , it would've been there before , I just wonder how long this had been going on.
It wasn't doing it every round , but more than enough that I checked it everytime I fired "except when I brain farted"

demented · « **Reply #23 on:** June 06, 2008, 06:46:54 AM »

I wasn't saying this was caused by excess headspace, just a bit of advice to anyone using Century built firearms.

SharonAnne · « **Reply #24 on:** June 06, 2008, 02:22:25 PM »

Demented,my apologies. Sound advice is always welcome.

~Ace~ · « **Reply #25 on:** June 27, 2008, 04:54:25 AM »

Lead
Bad Profile on Boolit

Much softer than Military primers... with Floating Firing pin = High chance of Slam Fire / Out of battery fire

A SKS fitted with a Spring returned FP or a CZ 527 would be a much better choice for your experimenting....

CCI Primers have to date yielded No problems for me with Slam fires in AK or SKS, not so with a couple other brands. The CCI are Harder I load allot of 123 grain V-Max in 7.62X39, Mainly for CZ 527's but get used often in the other guns.

Edited to add... in your pic it "Looks" like the bullet was seated to a depth that puts it Past the neck into the case... a No No with Lead, can also cause Very high pressure