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4x401
December 02, 2007, 23:08
Built my first Romy AK last week. Used a NODAK spud reciever and screws instead of rivets. I did pull the barrel from the trunion to remove the old rivets. Barrel was returned to trunion and pin replaced. The bolt DOESN`T close on a go OR no-go gage. Any idea`s what I did wrong or how I can fix it. Can someone explain the process or headspacing an AK to begin with? I thought I might try putting the gun back in my press and trying to move the barrel forward in the trunion enough to get the bolt to close. Sound reasonable?

mhg
December 02, 2007, 23:14
does it close on a live round?

Matt


All safety rules apply

4x401
December 02, 2007, 23:21
I don`t know. I don`t have any 7.62x39 ammo. :biggrin:
Guess I should buy some and find out.

motosapien
December 03, 2007, 05:26
Is the trunion cocked to one side or the other? Some receivers are warped a bit from heat treating and it can cause the trunion to not be in line with the receiver/ bolt. Eye down the barrel and see if it is parallel with the receiver.

I would first check it for function with live rounds and if the bolt won’t rotate into battery you may have to stone the rear of one of the bolt lugs to get it working. I had a 74 build with a slightly cocked barrel and that fixed it.

I'll bet it does function with live rounds though.

XHardrock
December 03, 2007, 06:19
Originally posted by 4x401
I thought I might try putting the gun back in my press and trying to move the barrel forward in the trunion enough to get the bolt to close. Sound reasonable?

Yup, or rap it with a hammer and brass bar If it's a matching kit it should have been headspaced correctly which means the barrel should move forward the amount you require.
Did you use emory cloth on the pin hole and barrel relief before reassembly?

If your positive the barrel is fully forward but headspace is still tight Motosapien mentioned the fix.

msnyder
December 03, 2007, 17:46
Did you use the BFH method of removing the the barrel? If so, you may have F'd up the chamber. Even if you used a press if you didn't protect the chamber, it may have been damaged. Post a pic of the chamber if you can. Matching numbers kit should have proper headspace.

gunplumber
December 03, 2007, 18:35
Originally posted by 4x401
Built my first Romy AK last week. Used a NODAK spud reciever and screws instead of rivets. I did pull the barrel from the trunion to remove the old rivets. Barrel was returned to trunion and pin replaced. The bolt DOESN`T close on a go OR no-go gage. Any idea`s what I did wrong or how I can fix it. Can someone explain the process or headspacing an AK to begin with? I thought I might try putting the gun back in my press and trying to move the barrel forward in the trunion enough to get the bolt to close. Sound reasonable?

you mean aside from using screws?

probably ok. when you tested, did you have the extractor in?: or does your gauge have an extractor clearance? easier to test w/ extractor stripped. its ok to be a VERY tight close. spec is 15kg pressure, which is something like 33 pounds.

it will probably close fine on a dummy round, or case with the bullet pulled, powder dumped, and primer popped.

only fools test in the shop with live ammo.

Hot Diggity
December 03, 2007, 18:37
Dumb question, but I'm sure some of the other older guys who wear glasses will understand. Are you sure you're using the 7.62x39 headspace gages?

If you've got the 7.62x51 gages in there it'll never close.

If you put the original pin back in place with the trunion and barrel that it came out of it is returned to the factory headspace setting and shouldn't be a problem. That is, if it was a matching number kit. (trunion, barrel and bolt numbers all matching.)

I'd recommend not pressing, beating, or forcing anything til you've done a thorough inspection of the chamber, checked the gages, and verified that the whole works is in fact 7.62x39.

If everything is correct you'll have to remove the barrel pin, and press the barrel
out until the bolt will close on a GO and not close on a NO-GO gage. Then you'll need to remachine the hole through the barrel and trunion to a larger pin diameter to correct for the offset of the barrel's original groove. Not much fun.

Recheck everything twice first.

HD

4x401
December 03, 2007, 18:42
Thanks for the responses. Yes, this is a matching numbers kit and I used a press to remove the barrel from the trunion. I`ll check it all out again and try all suggestions.

mj2evans
December 04, 2007, 11:58
Strip bolt and clean chamber and locking areas with break cleaner. Like has been said - no extractor and NO FIRING PIN when testing (with gauge or live ammo).

julysol
December 22, 2007, 17:53
I've seen same problem on a kit that was chopped fresh from the factory. Like they made it knowing its was to be sent to US, or pulled it fresh off the rack and cut it up. I really don't think they checked for fit and function, let alone headspace as there was a machining flaw and the trunion needed some touching up. Left lug had no room to rotate in trunion channel, like they had only done the rough cut and not final cut.
So, check engagement good with just the bolt not carrier so you get a good view. (you get a better view if there's no reciever in the way) ?Did you check to see if the bolt would fit and close within the trunion before you assembled it?

mhg
December 22, 2007, 19:39
Originally posted by gunplumber


only fools test in the shop with live ammo.

Mark, just to clear things up. I never suggested testing in the shop.

Matt

tracyballard
December 22, 2007, 20:51
Originally posted by gunplumber


you mean aside from using screws?



what exactly is the problem with using screws, other than being an obvious amateur job? Can a build be done properly with screws if you do it right? Do they really suck that bad???

gunplumber
December 23, 2007, 10:31
A rivit is a completely different fastenr than a screw. A rivit transfers energy from the receiver to the trunion. A screw does not. Screws are a poor choice in any high vibration application. There will always be those who try to rationalize their sloppy, lazy, substandard attempts with pathetic rationalizations such as "I havn't blown it up and killed anybody yet" but the wise builder will use the proven safe, effective rivit.

Why aren't boilers screwed together? Why not aircraft frames?

vmtz
December 23, 2007, 10:38
Originally posted by gunplumber
A rivit is a completely different fastenr than a screw. A rivit transfers energy from the receiver to the trunion. A screw does not. Screws are a poor choice in any high vibration application. There will always be those who try to rationalize their sloppy, lazy, substandard attempts with pathetic rationalizations such as "I havn't blown it up and killed anybody yet" but the wise builder will use the proven safe, effective rivit.

Why aren't boilers screwed together? Why not aircraft frames?

Threaded devices seem to work well in engine applications.

That being said, build with rivets. Makes for a nicer job.


Vince

tracyballard
December 23, 2007, 11:40
Originally posted by gunplumber

Why aren't boilers screwed together? Why not aircraft frames?


I assumed because rivets were easier and faster in an industrial setting like that, and being an auto mechanic I like high quality threaded fasteners. But, if you say rivets are the only way to go, that what I'm going to try...

mhg
December 23, 2007, 13:00
Mark,

In aircraft applications, rivets can be better in shear.

And I can buck 10-15 in the time it would take me to thread and drive one threaded fastner..

Matt

gunplumber
December 23, 2007, 14:01
Another assertion is that screws somehow are a stepping stone on the way to rivits.

This of course is without merit - there is nothing about drilling and tapping a hole that teaches one to rivit.

mhg
December 23, 2007, 14:12
Originally posted by gunplumber
Another assertion is that screws somehow are a stepping stone on the way to rivits.

This of course is without merit - there is nothing about drilling and tapping a hole that teaches one to rivit.

And riveting together a AK doesn't qualify one to buck rivets on a B2 either...

Matt

tracyballard
December 23, 2007, 14:35
Originally posted by gunplumber
there is nothing about drilling and tapping a hole that teaches one to rivit.

Well, I remember doing a few rivits back in 8th grade metal shop, so I should have that covered....just kidding, since I'm going with rivets I'll do some research and get something a step or 2 above the cheapest gun available...

gunplumber
December 23, 2007, 15:32
Curtis at AK Builder probably is the best source for quality rivits at a fair price.

sturmgrenadiere
December 23, 2007, 19:59
Doesn't quite fit the AK argument, per say, but seems that most of the "improtant" screws on any aircraft I have flown were also safety wired. Something undesirable about the slightest chance of an important fastener backing out while I am half way across the Atlantic. Call me cautious.

Rivets don't back out under "vibration". Any screw, be it on a small block head or rocker stud, or the prop on my aircraft, was torqued to a specific (and relatively significant relative to an AK screw build) value. Not sure if the screw build type screws could handle that sort of torque before becoming "nails".

And yes, rivets handle sheer loads better in these applications. But also note on an aircraft that there a lot more rivets per inch, relative to what you see holding cars together (screw wise).

Just something to consider...

4x401
December 28, 2007, 18:40
Update

My first succesful AK build, YEEHAA.
The tool runs like a scalded cat, no problems. :biggrin:
I knocked the barrel forward a bit in the trunion and it headspaced correctly. As a side note, it did chamber de-fanged ammo before the gentle nudge though. So a couple of you were correct about that. Sorry to get some peoples knickers in a knot about using screws. You`ll have to forgive my ignorance because I was only going on anothers advice to go that route, and it was easier for me. I`m going to try the rivet method on my next Romy, but I`ll still probably go screws on the Yugo RPK from Bocefus. :D

jefferyc22
January 03, 2008, 01:26
Originally posted by 4x401
Update

My first succesful AK build, YEEHAA.
The tool runs like a scalded cat, no problems. :biggrin:
I knocked the barrel forward a bit in the trunion and it headspaced correctly. As a side note, it did chamber de-fanged ammo before the gentle nudge though. So a couple of you were correct about that. Sorry to get some peoples knickers in a knot about using screws. You`ll have to forgive my ignorance because I was only going on anothers advice to go that route, and it was easier for me. I`m going to try the rivet method on my next Romy, but I`ll still probably go screws on the Yugo RPK from Bocefus. :D
geeze, trashen on a Romak is fine by me but that Yugo is 10 times the gun.........be nice to it:smile: