That Dumb Mainspring Again! (Ruger Mark III) Help!

akeefer · Feb 18, 2021

Hello all,

I finally upgrade my lower from a plain Ruger lower to a VQ Target frame with their mainspring. It will be matched up to my OPA (Oregon Precision Arms) Upper and it looks pretty sexy if you ask me!

Now, I'm no newbie to the MkII/MkIII/22/45 game so I'm well versed in the typical issues and have no problem stripping them down typically and putting them back together. That being said, I'm no gunsmith either, so it was also super disappointing to receive my lower yesterday and find I cannot get the mainspring to close at the last bit.

Yes, like the typical "hammer strut isn't seated in the mainspring cap" issue. (I've read the guntalk-online.com pages many times of the years.) So, I tried installing the mainspring without an upper on at all, and it seems like you have to really push the hammer super extra far forward, but it will close at that point.

I also tried installing the mainspring without the bolt installed. At least that way I could get access from the back to try to push the hammer farther forward. I did that, but it feels like the hammer is pushed up against the ejector and upper and will not go any farther forward. Looking at the ejector, it does seem like it sticks out quite a bit aft, but I'm not sure. I'm tempted to file a little bit of the rear of it to give a bit more space for the hammer to go forward more, but that's my best estimated guess.

Any other thoughts or help? I have emailed Volquartsen so hope to hear from them if they have any inside knowledge or if I'm doing something boneheaded or wrong.

Well, anyone throw some thoughts out there? It's almost a perfect .22... at least to me.

Maybe @Velzey or someone else would be willing to look at it? (I'd pay of course)

Thanks!

Grizzly_A · Feb 18, 2021

Take your grips off and check the different pins in the frame to make sure they are positioned correctly. I had a pin slip out of place and it created a very similar issue to the one you're describing.

I'm not familiar with the OPA, is it designed for the 22/45 or the MKIII frame? I wouldn't start filing except as a last resort.

I can take a look at it if you want.

akeefer · Feb 18, 2021

Ok thanks. I did take the grips off last night for a closer look. I'll probably take it down and lube and put back together and try again. Originally the OPA was on a MkIII frame, so I know it will work with that. I'm not gonna file until Scott Volquartsen says so

Grizzly_A · Feb 20, 2021

I had a TacSol on a MKiii frame and it was fine. I upgraded to the VQ frame and that's when my issue popped up. Lots of cursing and some sore thumbs were involved until I got all the bits in line.

drstrangelove · Feb 20, 2021

There are those who have cussed out their Ruger MK's and those who will but just don't know it yet. IMO one of the most needlessly complex disassemblies in the gun world.

Pepe-lepew · Feb 20, 2021

There is spring tension on the main spring when fully closed and hammer fully forward. It should close to within a 1/4 inch of fully closed, then push it in further to compress the mainspring to close the latch. With the bolt installed, the hammer will be pressing on the back of the bolt.

Put the bolt on your upper receiver. If it sticks past the ejector when fully closed your ejector is not a problem.

akeefer · Feb 20, 2021

I figured it out, all! I found the part that clips into the upper and faces aft was the issue. I talked to Scott Volquartsen and confirmed with him. I think the VQ mainspring is a bit thicker in that area. I filed that part down just a bit and it works perfectly! Yay! Thanks all that gave me info.