Installing MKII 22/45 Receiver on MKIII Lower???

johnnywitt · Post by **johnnywitt** » Tue Apr 07, 2009 8:28 pm

I have an extra MKIII Lower that I want to put an extra MkII 22/45 upper receiver on. THe Receiver doesn't seem to want to go on the lower. I have a Pac Lite that goes on both the 22/45 & MkIII lowers. So why won't the 22/45 receiver fit on the MKIII Lower.
I think I'm going to have to chamfer the lug recess on the 22/45 receiver. Am I on the right track here. I don't have a chamfer tool though, so I wonder what else can I use.
Paging Bullseye??? Bullseye to aisle 12

Yes, I know that I've finally confirmed my PIA status.

Post by **Bullseye** » Tue Apr 07, 2009 10:22 pm

This extra Mark III lower, is it a metal framed model? Your 22/45 receiver is peened on the underside, just over the front mounting lug recess. They do this to tighten the receiver down onto the plastic frame without damaging it. Some receivers will fit onto the metal frames without fitting but others don't fit. Now the main question, are you going to use this receiver on this frame exclusively? Because once you alter the receiver's peening, it will not fit tightly onto a plastic frame again.

R,
Bullseye

johnnywitt · Post by **johnnywitt** » Tue Apr 07, 2009 10:55 pm

Well, I guess I'm going to use it on the MKIII frame that I modded with the Clark Hammer Bushing and oversized sear pin. I also am running a VQ Sear and the factory trigger with the pre travel screw that you tapped for me.
I just took my Dremel and using the carbide cutter I very carefully relieved the lug recess and now I have an extremely tight fit on my metal frame. I test fired it 20 times into the ground (its dark) and it runs fine.
The Tac Sol Receiver goes on the 22/45 frame super loose, but once you drop the mainspring in it tightens up rock solid. I shot it while it was light outside and it functions good (once I positively engaged the magazine

) and I was hitting pop cans with Dynapoints at 20 yards consistantly. They make the Pac Lites to fit either the metal or plastic frames and boy are they loose on the plastic frame till you get the mainspring and bolt stop pin in. Its amazing how accurate they are being that loose on the plastic frame lowers.
Here's a picture of the Hybrid MkIII/MkII 22/45:

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Post by **Bullseye** » Tue Apr 07, 2009 11:15 pm

Well I see that you have it all fitted on the frame. The relief cuts you made to the barrel's front lug is what you needed. I was going to suggest a tool to fabricate for removing the peen dent but that's not necessary now. Time for you to go out and run some rounds through your new pistol.

R,
Bullseye