Advice on drilling into a bolt carrier

[1168]

I asked what exactly he was drilling and he never responded, so not exactly knocking anything. There is absolutely zero reason to drill into a carrier. Zero. The only possible reason would be if a fastener broke off and had to be drilled out. There’s no need to encourage and educate someone on how to compromise the integrity of a critical firearm component by doing doing something ignorant.

You said “zero”, twice, but then gave a reason.
There are two other possibilities. Trying to make a sidecharger, and experimenting with reduced mass using existing parts. I think both are bad ideas, but I have attempted one of them. Unsuccessfully.

This isn’t a particularly dangerous endeavor, just not a beneficial one.

[casualreclaimer]

One well known reason to drill holes in a carrier is to pin a weight in place. Like adding weight to some of the odd calibers to slow down bolt speed. It's done more often than you might think.

[DG23]

One well known reason to drill holes in a carrier is to pin a weight in place. Like adding weight to some of the odd calibers to slow down bolt speed. It's done more often than you might think.

You are one of the few here that actually has a clue sir...

[Mk401MOD0]

Quite curious as to how this turned out. Id be comfortable drilling the hole in a B port that's in good shape but tapping by hand would still make me nervous even using the machine for tap alignment. On all but the absolute best made drill press, with the table trammed and good spindle bearings I would be expecting less than optimal outcome.

IMHO the best way is to find a local job shop or small machine shop with a CNC mill and ask (or beg) them to drill/ thread mill. Rigid machine and high spindle speed with carbide drill and carbide thread mill would make really quick work of it. Shouldn't take long to program either.

[Austin26]

The hole is drilled and tapped but I am still waiting on another bit to create a level mating surface for the handle end. I hope to have it done in a week or so! So far it's been easy. Hopefully I won't destroy the upper or injure myself.

[Mk401MOD0]

Great success!

How did you end up doing it?

[Austin26]

A stub carbide drill bit that was, I think, 4.2mm. Then worked in the tap by hand. Just using a home drill press for the drilling and cutting oil and patience. I believe the bolt carrier is either an unmarked Aero or an unmarked ToolCraft.

Can you or anyone else think of a clearance issue? I'm going to cut a slot for the handle reciprocating. I can't think of any other problem. Likely going with a single use crush washer for the handle.

[Todd.K]

C158 or 9310, cobalt drill bits will work...

That’s bolt material, carriers are 8620