Filing down the third lug, need advice

[AZ-K9 0]

Recently bought a converted 308 off gunbroker and took it out yesterday with two FBMG 20 rounders filled with South African surplus. Major disappointment with probably 10 malfunctions in 40 rounds. I quickly learned what the problem is, the shoulder to the round waiting in the magazine has a serious dent/scratch in it and the bolt does not have enough intertia to pick it up after it's been dragged on the bottom of the bolt. I search here quickly revealed the third lug probably being the source of the bolt drag.

 

Additional searches didnt reveal any tutorials dealing with filing on the bolt lug. I've seen some indicate the lug has been entirely removed for some people with no ill effects, others say be careful to only remove the offending amount of lug that hits the round. My particular rifle seems to put quite a dent in the case so I'm concerned that my entire lug might have to go.

 

Any advice?

[Nick White 5]

Id say trial and error. I've only heard that filing it all the way down is a terrible thing to do. Read the thread here ".308 jamming". I was having the same problem and there's a link that someone posted and it really helped.

 

But to fix my problem (out of 40 rounds every secon shot would jam and it would dent and sometimes cut open the brass casing) I started shooting steel to wear down the lug naturally, and out off 100 rounds not a single jam. Everything went smoothly.

 

Found the link:

http://forum.saiga-12.com/index.php?/topic/62472-pictures-of-your-308-bolt/page__p__597301__fromsearch__1

Edited March 14, 2011 by Nick308White

[Spartacus 1,619]

Recently bought a converted 308 off gunbroker and took it out yesterday with two FBMG 20 rounders filled with South African surplus. Major disappointment with probably 10 malfunctions in 40 rounds. I quickly learned what the problem is, the shoulder to the round waiting in the magazine has a serious dent/scratch in it and the bolt does not have enough intertia to pick it up after it's been dragged on the bottom of the bolt. I search here quickly revealed the third lug probably being the source of the bolt drag.

 

Additional searches didnt reveal any tutorials dealing with filing on the bolt lug. I've seen some indicate the lug has been entirely removed for some people with no ill effects, others say be careful to only remove the offending amount of lug that hits the round. My particular rifle seems to put quite a dent in the case so I'm concerned that my entire lug might have to go.

 

Any advice?

 

 

Do not remove that lug!

 

Quite honestly, that type of work is not like fitting a mag or changing a butt stock.

Working on that bolt is critical to the safe and proper function of the gun.

 

Have somebody who knows what they are doing fix the problem. Your local gunsmith may claim to be an expert, but more than likely does not work on AK guns every day. I would suggest Tony at Tromix or Will at Red Jacket, etc. one of the vendors here that know exactly what your issue is and how to fix it.

[brokenfeather 2]

Check this forum list link. Someone on it might be able to help.

http://forum.saiga-12.com/index.php?/topic/61756-308-dinging-cases/page__p__590141__fromsearch__1#entry590141

Good luck keep us posted with the outcome. I still think the issue needs to be more completely resolved. JMHO.

[csspecs 1,987]

Field strip your rifle and take photos of the bolt showing the third lug from several angles.

 

My rifle dented brass cases on the first range trip. I switched to steel case ammo and the problem went away, now brass cased ammo is not a problem either..

[rgreg 0]

My 308 has the same problem. 2nd shell gets jammed and has the dent from the bolt. Where can you get a bolt from that is correct? I did a little polishing on it as the bolt looks like it was machined at the factory.

[Rhodes1968 1,638]

POLISH! Do not file that lug, here is where a dremel shines. Polish is all thats required you can always take more material off but putting it back is a mite tough. That link should show every surface that needs a bit of touch up.

 

Smooth as a politician's lies is what you are looking for here. Basically you are doing what normal wear will anyway, just doing it cheaper than firing a few hundred rounds of steel case.

 

Now some have noticed some types of mags being worse than others iirc, may want to look into it with csspecs.

Edited March 17, 2011 by Rhodes1968

[AZ-K9 0]

The dents are fairly substantial and polishing is unlikely to remove enough material to allow clearance. Im beginning to wonder if it is the magazine also contributing to the problem? Gonna go fire the stock mag and second check..

[AZ-K9 0]

 

Here is a photo of the damage done just by cycling the bolt back by hand. Clearly the lug is hitting the case at the mouth and beginning taper of the neck.

[Rhodes1968 1,638]

Seems css did a write up on this and some mags do have a greater upward pressure on the rounds. Polishing is all it took for mine is all I can say and yes the symptoms in your pic were exactly the same as I was seeing. I use Saiga, Surefire, and Csspec mags none now have any problem.

 

Its likely less material than you think that has to be removed. I used a dremel on med speed, polishing compound, and the polishing tip that comes in the kit from Demel. Thirty minutes of polishing and it was done. Shinny too....

 

Whats your bolt lug look like?

Edited March 21, 2011 by Rhodes1968