AR lower build problems due to Cerakote

[Olympus]

I was helping my brother build a lower tonight that he had Cerakoted. The coater got a little heavy and every single hole and recess had to be filed and sanded just to get the lower parts kit pieces to fit. After a long time, we got a majority done, but he ran into 2 pretty big problems.

First problem is the hole for the selector detent was coated with Cerakote. We filed the opening and got the selector detent in, but it won't come out now. This is a problem because the opposite end of the hole is gummed up too and the tip of the detent doesn't ride in the safety selector like it should. The safety operates, but there is no resistance because the detent can't got fully into place. So the safety switch just swings, which is not safe to operate at all.

Second problem is similar with the takedown detent. It can't go fully into the slot in the takedown pin because the channel is full of Cerakote. So the takedown pin can be fully removed from the lower.

Is there anything we can do? Especially about the safety selector? I'd say just pitch the lower and start fresh, but this lower is a consecutive serial number to one he already has and he doesn't want to lose that.

 

[rcmodel]

Number Drill bits.

Use hand turned for cleaning out holes:


#40 (.098"0 for Pivot & Takedown detent holes.

#22 (.157") for Safety detent hole.

#23 for Hammer & trigger pin holes.

1/4"x28 NF tap for pistol grip screw hole.

rc

 

[Olympus]

How do we get the selector detent back out though? It's stuck in its little hole.

 

[rcmodel]

I would try a drop of some bore solvent, or penetrating oil.

Followed by giving it time to soak.

Try pushing it in with a bent punch or stiff wire or something to get it to move, even a little.

Then beat the crabs out of it with a plastic hammer (away from the direction of the hole.)

Inertia might jar it out, eventually?

rc

 

[BBBBill]

You can always strip the Cerakote and start over....

 

[Olympus]

You can always strip the Cerakote and start over....

I don't know how we'd strip the coating out of all those little holes though.

 

[Olympus]

I would try a drop of some bore solvent, or penetrating oil.

Followed by giving it time to soak.

Try pushing it in with a bent punch or stiff wire or something to get it to move, even a little.

Then beat the crabs out of it with a plastic hammer (away from the direction of the hole.)

Inertia might jar it out, eventually?

rc

Thanks RC! I should have known you'd have some good advice. You're certainly a great resource for the forum!

 

[Olympus]

We were able to use small files and got pretty much everything else filed and working. The 3 detents and their channels are the issue.

The pivot pin detent is the better of the 3. It holds the pin in place and operates correctly. The pin is a little snug, but we figured that would improve with time as the Cerakote wears from use.

The takedown pin detent channel is so tight that the spring isn't strong enough to push the detent through the channel and into the groove on the pin. So the pin can be fully removed from the lower during disassembly.

The safety selector detent is by far the biggest problem. The detent is holding the safety lever in place. But again the detent channel is so tight that the spring isn't strong enough to push the detent to engage the safety selector. The selector operates just fine, but flops from fire to safety as you shake the gun. There's no resistance or positive click into safe or fire. And we can't remove the selector to push the detent back out from the top.