Ruger MKI

Recently purchased a 6 inch plus Ruger MK1. Removed the upper from the lower, or should I say, the upper tumbled off the lower once I removed the mainspring housing.

I tried to bend the front attachment lug, but it did not want to move, and I did not get a bigger hammer. Don't want to "fix it" in the old fashioned way, by breaking it!

To remove the upper from the lower on my two MKII's requires a rawhide hammer to knock them apart, but this pistol, (which is in great shape) the upper is surprisingly loose until the mainspring housing is attached, and then, it is more or less, tight.

Is this normal for MkI's?

I have just got the thing drilled and tapped, it has a crisp trigger, but Ultradot's are on back order. I removed the front sight as that undercut target sight makes for a great fishing hook, and the ones on my MkII's have removed a lot of meat from my hands. Till I took them off.

I am pondering what to do as I would prefer some rigidity between upper and lower, and I can think of a number of things which would work. Devcon, brass shims, etc.

There is a simple way to fix the looseness issue. Put the lower receiver upside down in a machinist vise and squeeze the lower at the top where the receivers meet. It will reduce the radius and tighten the upper to lower fit. I have done this 20+ times over the years and it works perfect. Those stamped and bent receiver are not true. The machinist vise trues them up slightly and gives you the fit you desire. Machinist vise will remain parallel during the squeezing unlike a typical bench vise.
Jon

Jon Eulette wrote:There is a simple way to fix the looseness issue. Put the lower receiver upside down in a machinist vise and squeeze the lower at the top where the receivers meet. It will reduce the radius and tighten the upper to lower fit. I have done this 20+ times over the years and it works perfect. Those stamped and bent receiver are not true. The machinist vise trues them up slightly and gives you the fit you desire. Machinist vise will remain parallel during the squeezing unlike a typical bench vise.
Jon

I tried something similar, and failed. I took a wide brass punch and a slap hammer and hit the side of the lower, to bend the arc in. Nothing happened except for a brass smear and some bluing loss. That lower must be made of adamantium.


But, your idea seems like a great idea. I am going to look for a bud who might have a machinist vise. Lifting the upper from the front attachment point will tighten things.


Thanks!

You can make shims out of a soda can. I have never needed to do this, but have seen pictures and details of how to do it in other forums. If you Google it you should be able to find several people showing how. But I think using the vice is the best method if you can.

A long time ago over on Rimfire Central I suggested drilling and tapping for a set screw on top of the lug.  It would take a few tries to adjust the set screw for a tight fit before Locktite would be added.  Never tried it but seemed like a good idea.
Now I use a piece of a target add one strip of Scotch tape and put that under the curved part of the lug out to the end of the frame. Then hammer slide and frame together.

The vise method is the only way to go. Shims will move or get lost.

I have never lost a shim. I don't see how that is even possible being that it is inside the gun???
Anyways, I think Jon's idea is great on a metal frame Ruger.  I have a 22/45 which is plastic.  If someone doesn't have a machinist's vise or has a 22/45 it's just another option that works.