So I bought a billet non reciprocating upper receiver for my SBR and settled on an Aero 7" M Lok handguard. I got the handguard and really like it, size is great for my hands, looks good, everything is great except for the barrel but setup is not nearly as nice as my Geissele but hey, it was $90 cheaper at $135.

When I went to check the fit on it it stopped about an 1/8th short. Tapped it a couple of times with a small rubber mallet and it didn't move at all. Turns out the Aero Enhanced handguard has a couple of "wings" for lack of a better term on the top of the rail end with a couple of "claws" that fit tightly on either side of the receiver picatinny rail to hold it in place and keep it from rotating at all. Well as you can see in the picture the side charging mechanism and frame of the receiver interferes with this wing not allowing it to seat all the way back. I dinged the aluminum and finish a bit trying to tap it on. No biggie but it bugs me.

So I'm considering my options. It doesn't look like altering the receiver is viable. However I'm pretty sure I could remove part of the "wing" on the handguard just enough to clear the spot it hits on the receiver like with the white line.

If I decide to go this route, how would you recommend I go about this? It's important to me that the corner be cut square and even.

The offending area


The proposed fix

Question:
How should I remove the material on the handguard?

Choices:
Clamp it down and go to work with a dremel and or filework for cleanup
Take it to a machinist, you're likely to botch it terribly
Take it to a gunsmith, you're so dumb if you fell in a bucket of tits you'd come out sucking your thumb.

 

You've got this.

Go slow, take less off than you think you need...file it for the last little bit. Sand it smooth, drink beer AFTER you're done...lol

It's only money...

If you relieved the handguard from the inside of that same area, will you be able to remove enough material so that the outside it still intact?

It looks like you have the right idea, but I'm wondering if a complete L-shaped cut that shows on the outside is necessary?

It extends beyond the outside of the handguard. Going to give this a whirl. Worst case it gets a little muffed and I'm the only one that notices.

I voted to go for it. I'm a machinist & I'd mill it because I can. However, You should be able to do the whole thing with a file(s) in about twenty minutes. I wouldn't get near it with a Dremel. For the amount you have to remove filing is a good option, IMO.

Whatever you decide, it's probably a good idea to have the barrel nut inside the hand guard if you're grabbing it in a vise.

quote:

Whatever you decide, it's probably a good idea to have the barrel nut inside the hand guard if you're grabbing it in a vise.

That's a solid tip right there. Thank you.

I'd go for it, but with how much you are taking off you might be happier with using hand tools than going at it with a dremel. A little aluma-black and you'll be happy.

If you file it, go slow, clean the file often, and use Birchwood Casy aluminum black finish on the new exposed metal.

I had to fit a Seekins/Primary Arms rail to my Gibbz side-charger upper for the same reason. File was impossibly slow so I took a mini air sander to it with some 60 grit discs. Finished with a file and then 600gr for a smooth finish and AlumaBlack to darken it again.

You'd be hard-pressed to tell its been modified. While a gunsmith can certainly do it, its not at all difficult. A small air saw might be best for your right angle cut need.

Here's mine, finished (besides waiting on the tax stamp for buying a proper stock of course):