WE M16A3 Open Bolt Grinding Feel
 

I'm having problems with my WE M16A3.

Every time I pull the cocking handle, the bolt and cocking handle kind of get stuck in the back position thus I'd have to push it forward manually and it has a "grinding" feel to it when I push it forward.

I've been diagnosing this for quite a while now and this is what I got from it: The stock hammer spring is making the hammer push too hard up on the bolt which tilts the bolt up and causing the front, top, tip of the cocking handle to grind right up on the receiver. I really can't figure it and I don't think it has anything to do with the rollers.

Anyone know how to fix this? Any help is very much appreciated.

Chris

Might be a stupid question but have you sufficiently lubed your gun? Also, make sure when you're pulling the charging handle that your rifle is not in the safe position on the selector.

I had a similar problem when I had my M16, it may be that your buffer retainer pin is not screwed all the way in, and the bolt is catching on it when its charging. Might want to double check its all the way in :)

Had the exact issue, try what debrief said, also take apart receivers, make sure everything is aligned correctly and make sure nothing moves and stays in correct position when assembling. Also make sure the latch isn't bent.

check the pin that holds the buffer, it should be low enough allow the bolt pass over it, and try to sand a bit the bottom of the bolt. Plus, lube it.

Have you installed a convertion kit from closed bolt?

If so, the auto-sear is 1mm longer on the open bolt trigger and will cause exactly that issue.

Thanks for the quick reply guys! I can assure you it's properly lubed lol

I just checked it now and it's already as low/tight as it can go. Tried removing it , putting it back in and lubing it, nothing has changed though.

It was also converted to OB from the Closed Bolt system but all the parts came from an existing OB gun, I did noticed the hight difference in the auto sear, so I made sure I swapped it out for the shorter one.

In case this helps, I have the RA-Tech steel bolt in with all the mods that turok_t posted to make it a lot smoother.

EDIT: Forgot to mention: When I pull the cocking handle back and engage the bolt catch, it becomes pretty hard to push the cocking handle back in and when does go forward, I can't release the bolt lock, it just gets stuck and it's impossible to release unless I pull the cocking handle back again.

Remove the bolt guide at the top and check for any burr or bad casting (the RA Steel bolt is cast then machined). It might hold the roller just a bit too high and cause you some trouble.

Are you using the stock open bolt or the RAtech bolt because you mentioned that you performs the mods on my guide? The mods were only for the RAtech open bolt.

I can almost bet you my life I know what the issue is. Its because the top edge of the bolt catch (Im assuming that you swapped for the open bolt catch since the closed bolt catch is different) is slightly higher causing the bottom side of the bolt to grind with the top of the bolt catch. To determine if this is the issue, remove the bolt catch and manually cycle the bolt again. If the problem is resolved, then you know that it is the bolt catch that is causing the issue. As such, try sanding the top edge of the bolt catch a bit, and cycle the bolt until it is smooth.

You have a WE OEM Bolt Carrier you can test with? I ended up having to sand the bottom of my carrier to get it to cycle smoothly. I also had to slightly sand my bolt catch (Which is steel, apparently) to get it to not drag too badly.

Just take the bolt catch completely off and see how it cycles then.

Awesome, you guys were right about the bolt catch. I filed the top of it a little and it's definitely smoother than before. :D

But the cocking handle still feels like it has a bit of friction when it slides back forward. I cleaned off all the lube on it, put it back in and racked it a bunch of times and when I took it out, I noticed a lot of metal shavings on the top of the cocking handle at the very front (that little nub that sits slightly higher than the rest of it). Assuming that's where the main point of force that's being pushed up is going.

To me it still seems like the hammer is pushing up on the carrier too hard which pushes up on the cocking handle putting more friction on it than needed. (Unless that's just how these are built, then I guess there's nothing I can really do about it?)

Thanks for the help guys!

Common diagnosis based on the symptoms you describe..i guess i was right with the bolt catch