Hardware Talk: Midwest Industries Receiver Block

by Tommy Grant

If you want to install the fire control parts and see down into the receiver, just slide the narrow part up into the magwell and clamp the big part in your vise.

Handling an AR-15 lower—while also assembling it, tightening something or just making it behave—can be a hassle. Midwest Industries (MI) has a solution, and their lower receiver block serves you in two ways.

First, you can simply slap the block down on your workbench and fit the receiver into it, nestled in place. It’ll stay put while you install the hammer and trigger pins and the trigger guard, even making it stay put while you hand-screw the buffer tube in place. (You’ll need more than the MI block to do the torquing and staking.)

While you’re doing this, the smaller section of the MI block has a recessed tray, where you can put the small parts you’ll need. No worries about them rolling off the bench or getting bumped by an inadvertent sleeve or put-down screwdriver. Nope, they’re safe in the recess.

If you want to view the interior as you install the fire control parts, you can. Simply take the block and slide the narrower part up into the magazine well. Yes, it’s shaped like a magazine for a reason. Now, clamp the bigger part of the MI block in your vise. You can now work on the lower, install and inspect as they function, or the fire control parts, without having to juggle the receiver in one hand while working with the other.


Being bright blue, it won’t glare in your shop lights, but it also won’t let parts hide, as a black or dark material might. Also, as a relatively soft polymer, it won’t ding your lower or mar the finish. I know some of you want to keep your build as pristine as possible. (Some of us use our rifles.)

As if all this wasn’t enough, MI added one more function: a gas block gas tube installation recess. The hard part of getting a gas system assembled can be getting the blasted tiny roll pin driven into the gas block, with the gas tube in place.

I dare you to find a non-marring position in your bench vise to clamp the block in, with an orientation of the gas block that allows you to drive the pin in. I’ve been wrestling with AR-15s for 35 years now, and that’s the part I hate the most.

The block is designed to work with forged receivers, so if you have a milled one, it might not be as nice a fit as MI intended it to be. They offer it in AR-15 and AR-10 sizes in one color: blue. Now, I’ve been wrestling with AR-15s for so long that I have some bad habits. I’ve found workarounds to get things done … doing them without fixtures. But I’m going to have to add this to the AR-15 toolbox, because it’s so useful for the things it does that it earned space in the kit.

Forty bucks may seem like a bit much for “a simple piece of plastic,” as one person I showed it to commented, but don’t be fooled: Not 5 minutes later he was asking to borrow it.

Editor’s Note: This article originally appeared in the March 2022 issue of Gun Digest the Magazine.

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