Mk III receiver to grip fitting

[dek]

I have a Mk III 22/45 w/hunter style 4.5 in bbl that I'd like to change to a Mk III grip. When fitting the upper to the grip frame, which part is fitted? As they are now, they will not fit. It appears easiest to file the slot on the upper receiver and increase the bevel to receive the lower grip catch. Anyone have any experience with this? And, is using a dremel w/steel cutter advisable or just go slow with a file? Thanks

 

[rugerguy]

take your time and use a file, go slow and keep checking, file the upper , NOT the grip frame ,at least you cqn put the old one back on if you ever have to...its when you come across a 'spare' or 'extra' grip frame, THEN you can modify that instead, six of one, half dozen of the other........

 

[NikA]

It sounds to me like he has a spare grip frame he is hoping to fit to a receiver. If I remember correctly, the grip frames (at least the all-steel ones) have a casting in a hook shape at the from that is pinned in and that holds the grip frame to the receiver. If I were doing the fitting, that's what I'd be working on since it can be replaced. On aftermarket grip frames, it looks like this piece is actually removable for just this purpose.

 

[SGW Gunsmith]

I have a Mk III 22/45 w/hunter style 4.5 in bbl that I'd like to change to a Mk III grip. When fitting the upper to the grip frame, which part is fitted? As they are now, they will not fit. It appears easiest to file the slot on the upper receiver and increase the bevel to receive the lower grip catch. Anyone have any experience with this? And, is using a dremel w/steel cutter advisable or just go slow with a file? Thanks

Here is a Ruger Mark III 22/45 upper showing how that upper was fit (tightened) to the grip frame at the Ruger factory. The assembler will smash the rear of the receptacle until the fit is tight.



Now, if you want to move that upper to a different lower grip frame assembly, you just might get lucky and it will fit OK. More likely, you will need to remove some of that smashed metal so that the radiused tab in the front of the grip frame will fit into the receivers receptacle for it.
Accomplishing that task with a small needle file is do-able, as long as you have the patience of Job. I prefer the Dremel tool and a carbide bur-bit with the rheostat turned down to a low speed to control the metal removal much better.