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View Full Version : What happened to my AK? Can it be fixed?


Raiz
10-07-2012, 10:10 AM
So I went to the range for the first time after building my AMD-65 at one of the local meetups. After about 120 rounds, my buddy noticed that the receiver was bent at the back. I tried to take the dust cover off, but it wouldn't budge. The spring button was stuck in position and wouldn't push forward. I had to push extremely hard, but eventually got the dust cover off.

It appears as though the rear trunion is tilted back, the rivet holes have been stretched, and this caused the back of the receiver to bend. I assume this whole issue is due to the recoil created when firing the weapon. Here are some pictures.

http://imageshack.us/a/img841/9186/20121007105136.jpg

http://imageshack.us/a/img844/6869/20121007105127.jpg

http://imageshack.us/a/img259/5757/20121007105115.jpg

http://imageshack.us/a/img138/3363/20121007105050.jpg

http://imageshack.us/a/img651/5544/20121007105034.jpg

Can this be fixed? Do I need a new receiver? What I bought was the Hungarian AMD 65 Receiver Flat from AK-Builder.com. If I need a new receiver, is there a thicker version available that wouldn't bend so easily?

I'm really sad right now. :(

CK_32
10-07-2012, 10:13 AM
In before the arsonal/must spend $3k on an AK guys show up ;)

CK_32
10-07-2012, 10:23 AM
But on the serious hammer it back into place and find someone who can do a quick spot weld and go on your way before you look at buying a whole new high priced receiver.

Skip to 3:40.
KvrG4T2K4sE

See that's not so bad ;)

tlillard23
10-07-2012, 10:49 AM
just hammer it back in place and figure out how you Bent it in the first place. I'm not buying the recoil bending it .

m03
10-07-2012, 11:18 AM
Although I've never built from a flat, some thoughts:

1) Was the flat fully heat-treated after bending, or just the pivot-holes?
2) How does the rear of the carrier look? Is it possible that the rear trunnion is too far forward, causing it to be hammered by the carrier?
3) Those right-side rivet heads don't look so good.

Raiz
10-07-2012, 11:26 AM
Although I've never built from a flat, some thoughts:

1) Was the flat fully heat-treated after bending, or just the pivot-holes?
2) How does the rear of the carrier look? Is it possible that the rear trunnion is too far forward, causing it to be hammered by the carrier?
3) Those right-side rivet heads don't look so good.

1. During the build party we heat treated the rivet holes until blue, not the whole receiver.
2. I'm not sure how to check that. Can someone please advise?
3. Not sure what to say about this one.

Raiz
10-07-2012, 11:30 AM
just hammer it back in place and figure out how you Bent it in the first place. I'm not buying the recoil bending it .

Well, then what did it? It was in perfect condition before I went to the range. I had just installed the hogue grip a day before. We fired about 120 rounds, and that's what it looks like. The only time I left the gun was to walk down range and change the target and there was no way the range officer let anyone near their rifles during that time.

AVID HUNTER
10-07-2012, 11:32 AM
To me, it looks as though there was an amount of side or rear force put on the folding stock which created the issues with the rear two rivets and bent the flat. It really looks like someone used the stock as a pry bar. I seriously doubt that recoil caused this.

If it was mine, I would replace the receiver, but there maybe many that will say just to bend it back.

chead
10-07-2012, 11:33 AM
I'm guessing it didn't get sufficiently heat-treated, since it egged out the rivet holes. I have the same kit and receiver from AK Builder, and it's been fine, but that's not to say you couldn't have had a lemon.

You could probably fix it by hammering and welding like someone already mentioned but frankly I'd go with a new receiver. A flat is going to be $30 and it'd be worth it to me for piece of mind.

The only other think I would think might cause that is if it's horrendously over-gassed but it seems really unlikely.

AK47American
10-07-2012, 11:39 AM
Aren't you supposed to heat treat the entire reciever?? Im no expert, but that is what I have heard at for previous builds. People who skip that step usually end up with enlarged rivet holes and rivets falling out of the reciever due to recoil and heat from shooting. Try hammering it all back in place then heat treat the entire reviever.

klewan
10-07-2012, 11:55 AM
Aren't you supposed to heat treat the entire reciever?? Im no expert, but that is what I have heard at for previous builds. People who skip that step usually end up with enlarged rivet holes and rivets falling out of the reciever due to recoil and heat from shooting. Try hammering it all back in place then heat treat the entire reviever.

They heat treat the hammer and trigger pin holes, not the entire receiver. The rivets letting go, I would think it's something to do with how the rivets were set. Or the bolt carrier is hitting the rear trunnion with more force than usual. The recoil/return spring is supposed to cushion that, I'd be looking at the spring and is it sacked out.

$P-Ritch$
10-07-2012, 11:58 AM
Standard practice that I have seen and heard is just heat treat the holes. I only have one build under my belt but it has held up just fine and the guys who helped me definitely knew their stuff. Heat treating the whole receiver seems impractical and not needed for home builds.

tujungatoes
10-07-2012, 12:25 PM
Yes it can be fixed. The rear trunnion will need to be removed, the receiver bent back into shape, and the rivet holes welded shut and re drilled.

The bigger question is why did this happen. If the trunnion is beating itself out of the receiver it's either WAY over gassed or the recoil spring is toast. Where did the kit come from/who did the population?

ptoguy2002
10-07-2012, 12:28 PM
Looking at picture #1, its hard to tell, but it looks like you may not have fully crushed the rivets. Hard to tell again, because even an ugly rivet head will hold, but those look to be sticking out too far.
Looking at picture #3, it looks like the swell neck of the rivet is sitting above the receiver, not flush, which means that you didn't dimple the receiver for the swell neck on the receiver before putting it together. The visible hole on the other side which doesn't look like it has a dimple would appear to confirm this in pic #2.
IMHO, just looking at the pics, I'd say improper assembly.
The receiver is steel, anything steel can welded / ground / cut / re-welded again, and be saved, but IMHO, probably not worth the time considering you'd have to demill the rear end anyway for a "proper" fix. I'd say start with a new flat for best results. And if you didn't dimple the rear, you probably didn't dimple the front either.
If you wanted to do some impro welding....you can save it...

ETA: Post a pic of the front trunnion rivets. Angled, so we can see if your front swell necks are flush with the receiver or not.

savagemann
10-07-2012, 12:33 PM
1. During the build party we heat treated the rivet holes until blue, not the whole receiver.
2. I'm not sure how to check that. Can someone please advise?
3. Not sure what to say about this one.

So wait....
#1
You guys heat treated only until blue?
For a full heat treat you heat it until glowing red/orange and quench in water or oil.
Then bring it back to blue to soften it a bit.
If you skipped the red/quench, I would say the rear of the receiver could be too soft.
Somebody correct me if Im wrong.

Sent from my SCH-I510 using Tapatalk 2

Bug Splat
10-07-2012, 12:38 PM
Yes it can be fixed. The rear trunnion will need to be removed, the receiver bent back into shape, and the rivet holes welded shut and re drilled.

The bigger question is why did this happen. If the trunnion is beating itself out of the receiver it's either WAY over gassed or the recoil spring is toast. Where did the kit come from/who did the population?

Thats a very good point. I can't see how normal recoil could do that much damage. I think Tujunggatoes is right, the bolt carrier could be beating the hell out of it. I'd expect that kind of damage if you were beating down doors with the butt but not from normal shooting.

6mmintl
10-07-2012, 12:52 PM
Looks like Cheap (soft) receiver material or oversize rivet holes in keeping with the known problems of home built AK's.

Maybe try a countersunk reciever hole and a flat head allen screw to give more bearing surface in the repairof (soft) receiver material once you straighten it all out.?

Redchevyman
10-07-2012, 12:58 PM
It looks like the holes were not dimpled and the rivets were not crushed into the dimples. Try to get the rivets out and flatten out the receiver. If the holes are not too egged out you should be able to get it back together. If not weld some metal back onto the holes. I can send you a couple long rivets if you need them. Just PM me with your address.

CptDan
10-07-2012, 3:35 PM
I'm wondering how big the gas port hole was drilled, It looks like the trunnion was slammed out the back of the rcvr.

Raiz
10-07-2012, 5:07 PM
Yes it can be fixed. The rear trunnion will need to be removed, the receiver bent back into shape, and the rivet holes welded shut and re drilled.

The bigger question is why did this happen. If the trunnion is beating itself out of the receiver it's either WAY over gassed or the recoil spring is toast. Where did the kit come from/who did the population?

The kit is the same one you see on a lot of sites. It's the AMD-65 kit that ranges from $160 to $250 depending on which site you visit.

If by population you mean fitting the barrel, it was done by 69Mach1 from here on the forums. I attended a build party in the OC with the guys here in the forum. As I don't have much experience with riveting I trusted the people at the party to know when the rivets were pressed properly.

Raiz
10-07-2012, 5:12 PM
Also, the holes were heat treated like you said.... heated once, then dunked, then heated again. I had oversight through the whole process.

How can one tell if the recoil spring isn't working properly? It seems fine from what I see.

Would a local gunsmith in Long Beach know enough about an AK to know what to do?

tujungatoes
10-07-2012, 7:25 PM
The kit is the same one you see on a lot of sites. It's the AMD-65 kit that ranges from $160 to $250 depending on which site you visit.

If by population you mean fitting the barrel, it was done by 69Mach1 from here on the forums. I attended a build party in the OC with the guys here in the forum. As I don't have much experience with riveting I trusted the people at the party to know when the rivets were pressed properly.

OK....We know the people that did your population and helped you build know what they're doing. You also said you used ak-builder hardware so I really doubt the receiver alloy would be a problem....I'm fairly sure we can cross any assembly issues off the list. I'd be looking real hard at the recoil spring. I couldn't see it in the pictures, but I'd be willing to bet there are fairly obvious signs of the carrier and rear trunnion making contact. I'm not familiar with any smiths in the LB area so couldn't tell you who to see locally. I'm in the SFV and would be happy to take a look. Unfortunately my welders and build tools are in storage until further notice, so not sure how much actual help I can be. Wolf gunsprings makes new recoil springs. I think they're less than $20, but don't buy until you get the receiver sorted out.

*edit* I'm gonna talk to the guys and see if we can't find a way to get you back in working order in the very near future.

RobGR
10-07-2012, 8:17 PM
How is the ejector looking, all beat up?

saki302
10-07-2012, 10:49 PM
I'm guessing the thing is over-gassed and beating itself to death.

Even using horribly and improperly done rivets, I don't see them failing in 120 rounds.

I've also never heard of heat treating the rivet holes. I've fired a case of ammo through my junker built on a tapco flat (thin flexy thing), with no rivet hole issues. This is why I really suspect your gas port is too large.

-Dave

tujungatoes
10-08-2012, 5:19 AM
I didn't think to ask before, but what is the make of the barrel on your rifle? Was it a US made bbl with the gas port already drilled?

451040
10-08-2012, 5:30 AM
Can it be fixed?


Buy an AK tool kit and fix it yourself:

http://diehipster.files.wordpress.com/2012/02/sledgehammer.jpg?w=300&h=225

ptoguy2002
10-08-2012, 7:37 AM
Raiz: Did you dimple the rivet holes into the trunnion before you pressed the rivets?

Raiz
10-08-2012, 11:47 AM
OK....We know the people that did your population and helped you build know what they're doing. You also said you used ak-builder hardware so I really doubt the receiver alloy would be a problem....I'm fairly sure we can cross any assembly issues off the list. I'd be looking real hard at the recoil spring. I couldn't see it in the pictures, but I'd be willing to bet there are fairly obvious signs of the carrier and rear trunnion making contact. I'm not familiar with any smiths in the LB area so couldn't tell you who to see locally. I'm in the SFV and would be happy to take a look. Unfortunately my welders and build tools are in storage until further notice, so not sure how much actual help I can be. Wolf gunsprings makes new recoil springs. I think they're less than $20, but don't buy until you get the receiver sorted out.

*edit* I'm gonna talk to the guys and see if we can't find a way to get you back in working order in the very near future.

Thank you tujungatoes. What I really need is someone more familiar with AK's than myself to take a look at this and figure out what is happening. If it costs me a little out of pocket, that's ok as long as I can get back to shooting again. I just need to know where to go and who to talk to.

Despite the unhappy ending of the range trip, I had a great time putting rounds downrange and want to do it again asap!

Raiz
10-08-2012, 11:56 AM
I didn't think to ask before, but what is the make of the barrel on your rifle? Was it a US made bbl with the gas port already drilled?

The barrel is a 14.5 inch barrel sold by armsofamerica.com.

http://armsofamerica.com/amd-65762x39145inchthreadedbarrel.aspx

I paid the extra $24.99 to have Superior Plating chrome line it before it shipped to me.

http://armsofamerica.com/chromeupgradebysuperiorplating.aspx

Raiz
10-08-2012, 11:59 AM
Raiz: Did you dimple the rivet holes into the trunnion before you pressed the rivets?

I honestly don't remember.

jokat989
10-08-2012, 2:01 PM
i would loose the rivets and weld the sucker back up. similar thing happened to me, the whole rear trunion ended up separating from the rifle(good thing i was bump firing lol).

4thSBCT
10-08-2012, 2:14 PM
Shotty rivet work is to blame here,

I'm pretty sure it went down like this,

Rear holes were drilled misaligned and then egged out to be corrected (not necessarily a bad thing) then followed up by non dimpled poorly set long rivets.

Setting the rear rivets properly would've filled any gap or imperfection in the receiver, unless the rivet was set improperly and just folded over as seen by the ob long strange looking head that was formed.

That recoil spring looks damn near new, and if mach set up the barrel, gold, diamonds, and puppies might come pouring out of the barrel.

A repair is possible but unless your a metal fab pro it wont be pretty, I'd rebuild it.

Ryan in SD
10-08-2012, 2:17 PM
1. During the build party we heat treated the rivet holes until blue, not the whole receiver.
2. I'm not sure how to check that. Can someone please advise?
3. Not sure what to say about this one.

Blue is the incorrect color.

Probably annealed it (made it softer)

I would drill out the rear rivets, then weld up the egged portion, then dremel them round and to size and re rivet.

Ryan in SD
10-08-2012, 2:21 PM
Looks like Cheap (soft) receiver material or oversize rivet holes in keeping with the known problems of home built AK's.

Maybe try a countersunk reciever hole and a flat head allen screw to give more bearing surface in the repairof (soft) receiver material once you straighten it all out.?

This is just wrong.

You are so hard headed when trying to push your screws vs rivets :rolleyes:

honestly who wants a flat head on their AK ???

tujungatoes
10-08-2012, 7:21 PM
Even if the rivets were just slipped through and not set, and the receiver was made of aluminum the trunnion wouldn't be beating itself out of the receiver if something wasn't wrong.

wash
10-08-2012, 9:29 PM
I'll have to look at an AMD trunnion to see if the rivet holes are chamfered.

If they are chamfered, the receiver wasn't flared in to the chamfer and the rivets are not swell neck, there could be maybe 0.050" of unsupported rivet shank between the receiver and rivet hole. Any force on the rear trunnion is going to want to bend that unsupported shank in to a "z" shape which might explain the bent out piece of receiver.

I've got an AMD pistol build in the works (using a modified AMD side folder trunnion in a no trunnion hole Romanian style fixed stock flat) and I think this might push me toward heat treating the rear trunnion holes to make it harder to pull out.

I'm also picky about my rivet setting, those rivet heads would not pass my eye check.

nicoroshi
10-09-2012, 4:31 AM
Yes it can be fixed. The rear trunnion will need to be removed, the receiver bent back into shape, and the rivet holes welded shut and re drilled.

The bigger question is why did this happen. If the trunnion is beating itself out of the receiver it's either WAY over gassed or the recoil spring is toast. Where did the kit come from/who did the population?

This^^^^
Over gassed system or weak recoil spring (or both).
After you repair the receiver replace that recoil spring.

TF_CAM
10-09-2012, 7:26 AM
Looks like it wasnt heat treated properly..

chead
10-09-2012, 2:12 PM
This is just wrong.

You are so hard headed when trying to push your screws vs rivets :rolleyes:

honestly who wants a flat head on their AK ???

Friends don't let friends do screw builds.

wash
10-09-2012, 3:11 PM
All four holes are chamfered.

Crummy rivets.

Either weld, redrill and reset the rear trunnion rivets (with good heads on swell neck rivets) or demil and start over.

Also make sure your recoil springs are good.

SJgunguy24
10-09-2012, 7:40 PM
Even if the rivets were just slipped through and not set, and the receiver was made of aluminum the trunnion wouldn't be beating itself out of the receiver if something wasn't wrong.

This.
That gun is overgassed and or the recoil spring is toast.

Raiz
10-09-2012, 10:28 PM
Overgassed seems to be the consensus. I've looked at the spring and it doesn't look out of the ordinary. When I got the kit everything looked like it had never been used... just built and then demilled. I will let ya know what we find.

stilly
10-10-2012, 10:48 AM
Although I've never built from a flat, some thoughts:

1) Was the flat fully heat-treated after bending, or just the pivot-holes?
2) How does the rear of the carrier look? Is it possible that the rear trunnion is too far forward, causing it to be hammered by the carrier?
3) Those right-side rivet heads don't look so good.

I R a NOOB. I built my AK pistol at a build party and only the middle of the receiver was heat treated or the pivot holes.(the two big X holes). Mine has been fine. Heat up till it turns red, drop it in the salt water, heat it up again till it turns purple, drop it in the salt water, let it dry. Or something like that.

I have put about 400 rounds through mine now and my bolt carrier is hitting the rear trunion and making the gas piston come out and hang on the gas block, but that is only because there is a slightly longer pull for it, once I get this part fixed it will be good to go and I am going for a recoil spring fix. SO, maybe it is a really worn recoil spring. It also might not hurt to put a buffer there and see if it happens again after it is fixed. If you went to a build party that was NOT put on by the AK-Team then I can not comment. I am fairly certain though that their build parties are great. I can not wait to go again and make a rifle. Heck, I was even thinking of cutting my io in half just to have another parts kit to match my flat and rebuild it (nothing is wrong currently, I just like the idea of remaking my own).