View Full Version : tantal/ak74 issue
A friend of mine has a polish tantal. Its a custom build on a nodak spud reciever. He bought it on gunbroker and the builder is unknown. He had all the internals, including bolt and boltcarrier industrial hard chromed, which only adds .001" or so according to the chromer. We also applied duracoat to the entire gun(except for the chromed parts.) I dont know if any of that could possibly cause the following, but I put it out there just in case.
ISSUE: We've only shot steel(5.45x39mm) through it, both corrosive and non-corrosive, and the base of the case, from the rim(but not including the rim) up about 1/8" from where it starts, is bulging. Any idea why? We first noticed it when we were shooting it as fast as possible, and I though it may be firing out of battery(before I knew better) but he shot it again today(after 2 years) and it still happened, I think every round. Now Im thinking the barrel is ****ed. He doesnt have calipers, but Ill try and have him get a pair and measure the chamber. Any other ideas of what is causing this? Also, if the chamber is out of spec, is this an issue? What could happen? Or is it not a big deal.
Sorry for the long post, and thank you.
Get a set of go/no go head space gauges and see that's going on. In an AK you set headspace on assembly by pressing the barrel to fit the bolt. Any number of issues could cause your symptoms. Checking headspace is a quick way to eliminate/identify most.
Is the barrel factory original or was a US made barrel used?
Is the barrel factory original or was a US made barrel used?
supposed to be polish factory barrel. Its definitely chrome lined, and its really accurate, no keyholing.
Ill have him ask around about the headspace gauges, see if anyone has one for 5.45. I didnt even think about that. If there is too much headspace, any potential dangers? Gun has about 1k through it, so does that mean it must be ok or is there a chance of a kaboom in the future? Mainly Im curious about the reason, my friend just knows its not right and wants to make sure its safe. Ill call him tomorrow and keep you posted when I hear back. Thanks guys.
Be careful! Headspace issues can result in injuries and ruined guns.
Sounds like a headspace issue from your description. Does the bolt serial number match the front trunnion? If they are mismatched, it could be a case where the builder just assumed that the headspacing would be ok... It's not like an AR, you can't just swap bolts with an AK rifle and expect it to be safe to shoot (just in case that's what has happened).
When you remove the handguards, are there factory proof marks on the barrel? This is a quick way to tell if you have a factory barrel or not. If it is indeed factory, there should be several markings on the barrel. US barrels are frequently without any markings at all.
Also, if you get your hands on some headspace gauges, make sure to remove your firing pin and extractor first before you use them. You can do so fairly easily with a small punch.
Good luck, and pictures might help folks diagnose the issue.
A friend of mine has a polish tantal. Its a custom build on a nodak spud reciever. He bought it on gunbroker and the builder is unknown. He had all the internals, including bolt and boltcarrier industrial hard chromed, which only adds .001" or so according to the chromer. We also applied duracoat to the entire gun(except for the chromed parts.) I dont know if any of that could possibly cause the following, but I put it out there just in case.
ISSUE: We've only shot steel(5.45x39mm) through it, both corrosive and non-corrosive, and the base of the case, from the rim(but not including the rim) up about 1/8" from where it starts, is bulging. Any idea why? We first noticed it when we were shooting it as fast as possible, and I though it may be firing out of battery(before I knew better) but he shot it again today(after 2 years) and it still happened, I think every round. Now Im thinking the barrel is ****ed. He doesnt have calipers, but Ill try and have him get a pair and measure the chamber. Any other ideas of what is causing this? Also, if the chamber is out of spec, is this an issue? What could happen? Or is it not a big deal.
Sorry for the long post, and thank you.
The AK you purchased is junk.
The AK you purchased is junk.
Not mine, a friends, he said NO markings on barrel whatsoever... ****.
He might sell it and have a similar one rebuilt from a real complete kit... how much does it cost to have headspace adjusted on an ak, rough estimate?
Not mine, a friends, he said NO markings on barrel whatsoever... ****.
He might sell it and have a similar one rebuilt from a real complete kit... how much does it cost to have headspace adjusted on an ak, rough estimate?
It might not be so bad. Basically, the barrel would need to be pressed in a tad and the barrel pin channel enlarged (re-drilled) to a bigger diameter, then a new and larger barrel pin would be installed. Refinish, etc.... There are potential issues (if the builder already fubar'd the barrel pin install, and a couple other potential problems). But, all in all it might not be so bad to fix.
Heavy Metal
11-08-11, 12:30
Call Troy Sellars at Inrange.
Definitely borrow a set of gauges and stop firing it until it is checked.
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