Back Plate Stuck on Threads

[jmoney]

Had a weird issue shown to me this morning. On a standard colt 6920 a friend was attempting to swap out the back plate for a sling attachment. After taking of the buffer tube the plate is stuck on the threads. It has a little bit of wiggle, but the thing is not budging. Anyone have a method for getting this thing off without damaging the threads?

[26 Inf]

Had a weird issue shown to me this morning. On a standard colt 6920 a friend was attempting to swap out the back plate for a sling attachment. After taking of the buffer tube the plate is stuck on the threads. It has a little bit of wiggle, but the thing is not budging. Anyone have a method for getting this thing off without damaging the threads?

If it slid on without damaging the threads it should slide off without damaging the threads.

Put penetrating oil on the part, position the receiver extension so the oil flows down through the threads. Give it a moment to soak. Try to move.

If that doesn't work, MY next step would be: re-thread the buffer tube slightly into the receiver; place it onto a vise mounted receiver block; get a crescent wrench or a pair of channel locks and adjust them in width so they are barely touching the receiver extension/buffer tube; place them so they are against the sides of the receiver end plate and GENTLY tap with a small dead blow mallet (or whatever you have).

As an alternative you could open a vise just large enough so the edges of the receiver plate are laying on the jaws. Take a piece of soft wood - a scrap of 2x4 would work, lay it on the end of the receiver extension and gently tap.

It is probably just tweaked enough that it is bound up, hopefully that will center it up and let it slide off.

[militarymoron]

They sometimes get wedged on threads when they're at an angle. Usually a wiggle is enough to loosen them. Maybe you can use the castle nut to help push it off after putting oil on the threads. That way, you make sure the plate is not at an angle.

[masenomics]

When I removed a receiver extension from a Colt expanse lower when they staked the end plate/castle nut the end plate got displaced/deformed to the point that it was very difficult to remove from the receiver extension.

[jmoney]

When I removed a receiver extension from a Colt expanse lower when they staked the end plate/castle nut the end plate got displaced/deformed to the point that it was very difficult to remove from the receiver extension.

That's what happened. Someone manned up and just cranked it off without damaging it.

[omegajb]

Had a weird issue shown to me this morning. On a standard colt 6920 a friend was attempting to swap out the back plate for a sling attachment. After taking of the buffer tube the plate is stuck on the threads. It has a little bit of wiggle, but the thing is not budging. Anyone have a method for getting this thing off without damaging the threads?

I think it's a common feature/flaw of the Colt's. I had the same problem with my 6920, it finally came off but it scratched the finish off some of the threads but didn't damage them.

[GrumpyM4]

Had the same here. Colt, machine staked so hard it pushed the end plate INTO the receiver extension and bulged the extension inward. Buffer and spring still moved freely though.

I ended up cutting off the end plate as it was under so much tension and easily replaceable. It actually made a "ting!" sound when the cutting wheel broke through and the cut end popped out about 1/4 inch.