I know this is probably a stupid question but have you throughly cleaned your chamber with a proper chamber brush? It could be a possibility that the previous owner shot Wolf lacquer cased ammo through it, this sometimes can lead to the lacquer from the casings to build up in the locking lug recesses and cause the bolt to stick. This has happened with many AR-15's and since the bolt design of the G36 is based on the M-16/AR-15 then it's not a stretch to assume this could be the problem.

Next thing I can think of is to check the bolt head itself for any burs or protruding metal that has been mushroomed out for some reason or another. This could be causing the bolt to grind and stick to the inside locking lug recesses, this malfunction would not lead to any marks showing up on the casings but could still be the culprit.

 

my first thought would be check the gas piston and operating rod, if they were not working then that would be why the bolt is locked up, because the piston isnt rotating it.

 

If he's unable to retract the bolt from battery manually then the operating rod and/or gas piston should not be a factor since they do not contact the bolt/bolt carrier group at anytime until the weapon is fired and it has reached that point in the cycle of operation. Now if this problem only occured while he was firing the weapon then I would agree.

 

Wow, you know after reading my post to me it seems as though I'm coming off with an attitude. Didn't mean it that way Liquidous, just typing out loud. Respect.

 

Oh I didnt read his post carefully enouph, I thought he was firing live rounds, sorry

 

This has happened with my rifle once or twice, I've found that it only happened when the round wasn't fully seated in the chamber because of dirt or something

 

This first happened at the range, the gun was disassembled and cleaned. Now it seems to still be locking up when I cycle hand fed dummy rounds with or without a mag in place.

The bolt "looks" fine with no obvious deformation or galling. It operates pretty smoothly when being hand cycled with no rounds. My guess is it may be a bolt problem but it isn't anything I can easly see.

Are there any gunsmiths around who are familiar with SL8-G36 hybrids?

Thanks for the help so far.

 

If I could actually look at it I'm pretty sure I could figure out the problem. As for sending it out to someone I'm not so sure.

 

You say it uses AR mags, meaning you either have an actual G36 bolt or an American made one from you know who. Which is it? Do you have the original SL8 bolt?

 

I don't know which bolt it has (G36 or modified SL8). Any clues I should look for to tell? I bought it already converted. Maybe I can send the bolt to someone to repair?

 

German bolt has HK symbols or markings.

 

If it's a US bolt, using the german extractor, the spring may not have been assembled properly. Was the barrel cut down or is it all original?

 

+1 on the extractor. If the extractor was mis-installed or is binding in the "open" position, this will cause the carrier from sliding out smoothy as well as prevent the round from ejecting.

 

I'll be the first to mention that the 'aftermarket' bolts that were released with "US-Parts Kit" guns using folding stocks could be short in the overall chamber length, leading to an issue with headspace. Given the strength of the HK factory barrel and chamber, I wouldn't this would cause issues with pressure or function, but you may find that using dummy rounds designed to the specifications of .223 would fit and work just fine, though longer ammunition may be getting either the bottleneck clamping it into the chamber or the bullets hitting the rifling.

This could be caused by a bolt head with the face cut too shallow.

Suggestion; get your SL8-1 bolt out and install it in your carrier, then try to chamber a dummy round. If it is silky smooth extracting/ejecting (like it should be), then your US made bolt is the problem.

One more suggestion; find another US-made part to swap out and use a German G36 bolt head - you'll never question whether it's in spec or if it's up to the task.

 

It appears the bolt head is a US made one, probably installed when the original owner did the TN conversion.

In looking at the parts diagram, there is both a spring and a "rubber pin for extractor" in the extractor assembly. Before I disassemble my extractor, is there a place to buy a replacement "rubber pin" or should I look at the "D-fender" rubber shim that is advertised?

Based on what folks are saying here, I think I'll check the extractor assembly first. When you buy a "complete" G36 bolt head, I assume there is no extractor assembly included?

I cleaned the bolt assembly, chamber and gently lubricated same but the jam problem still exists...although ALOT LESS.

 

Based on our phone convo, my money is still on the extractor.

When you buy G36 bolt-heads, they are usually complete If your extractor is damaged, you can probably buy an SL8 bolt-head for under $100 and use the parts from that.

 

I had a similar problem with mine and I'm pretty sure it's the headspacing on my US made bolt. Took it out shooting with three types of ammo that had worked on other military style .223/5.56 autoloaders. 100% success with two types of ammo, 100% failure with the third type. The failure was jamming of the round going into the chamber. Apparently the bolt was going forward just enough to be able to start to rotate before the lugs jammed against rear of the barrel extension due to excessive friction. Wouldn't fire as the incomplete rotation of the bolt prevented the carrier from going far enough forward to allow in-battery firing. Only fix was to beat on the charging handle until it came free and when it did, the unfired round extracted and ejected normally, and was undamaged. Given the fact that it worked fine with two types of ammo, I don't think mine was an extractor problem. Later at home, I cycled some of the same ammo using my original SL8 bolt, and it fed fine.

 

What ammo did you find worked? Your problem sounds exactly like what I am experiencing except it was never 100% failure, I was able to get some shots off between jams, but never a full mag worth.

I'm probably looking to buy a G36 bolt head and add the US made D-Fender rubber shim on the extractor spring.

 

Unfortunately, I don't remember what worked and what didn't. I'm thinking Norinco didn't. I've never used Wolf or any other steel cased ammo.