Friend of mine is having issues with his 15-22. The bolt is binding up somewhere and I can't figure it out. If it break the upper away from the lower, the bolt slides in and out with zero issues, but when the lower is put back on, it's super hard to charge and refuses to go into battery. It's rubbing/binding on the lower somewhere, but I'm not seeing any rub marks. Any suggestions?

Also, this is as far in as the bolt will go. To get it to seat all the way into the upper like it's supposed to requires me pushing the hell out of it. I don't know what's up with this thing.

After further investigating, it really looks like it's binding on the guide rails that it slides on.

Does the hammer reset fairly freely? That hammer really needs to be well greased. Also, in my experience, ensure the guide rails are parallel and are not torqued at all. I use Slip 2000 on mine. I put it on the top and bottom and inside of the guide rails, run the bolt down it a few times, and then wipe off the excess. Also, ensure the spring guide rod isn't catching. Please let us know what you find and good luck.

Hammer isn't binding at all. Guide rails are fitting in their respective grooves perfect. It is perfect until I have to shove it in that final 1/8" or so as you see in the pic (to clear lower receiver) then it goes to hell and is binding somewhere. Tried polishing the rails real good. That's not helping. It feels like when I push it in that last bit, it is causing the guide rails to push inward towards the bolt, causing the binding.

I give up. Cycling it over and over and over and over seems to be helping, but not much. I'm just going to suggest sending it back to S&W.

If you or another buddy has another bolt, try sliding it in.
That will at least narrow it down to a bolt or slide rail issue.

I am looking at my rifle.  It looks like the only thing it could be, is one or both of the rail guides, where they go into the "barrel extension" I guess it would be, not the ones in the receiver itself, either have an obstruction in them, or they are deformed.  That makes it hard to seat the carrier that last little bit, and when you force it in, it is warping the rails and making it very difficult to cycle the bolt.

Are the front of the rails rounded off so they won't cut into the guides?  If someone put a hard edge on them, I could see them digging into the receiver.  Matter of fact, I can see where the factory has left some left over sprue on the front.  I can see just see someone taking a file to clean them up, and leaving the them sharp as hell like an idiot.

I've seen this problem a dozen times on another forum.

99% of the time it's caused my someone not properly securing the barrel with a vice and blocks when removing/installing the flash hider, handguard, or barrel. Then the barrel spins inside the plastic upper and the guide rails and ejector are misaligned. Even if it only spins a slight amount it will cause issues. If this is the case a new upper receiver is needed since two plastic tabs had to break for the barrel to start spinning. S&W sells them for under $20.

If no mods have been done to the rifle then check for an extremely loose barrel nut.