Need your help, again...damaged MkII

[mwwilkew]

You all helped me greatly about 18 months ago and now I'm experiencing a different problem with the same pistol. Its a Ruger Mk II with the 10" bull barrel. Clark hammer bushing, VQ hammer, VQ sear, VQ trigger, VQ extractor.

I've mostly used this with a Tactical Solutions Pac-Lite barrel and it ran very reliably until about 2 months ago. At that point it started to have regular FTF. It still ejects reliably but as it feeds the next round the bolt seems to get hung up due to some sort of friction. When the bolt hangs up, a fairly light push will move it forward into battery. The bolt hangs up whether or not a round is being fed from the magazine. Once it is cocked with the hammer back, the bolt seems to move freely in the receiver. Here's a video showing this (obviously unloaded):
http://www.youtube.com/watch?v=kcj8fo-2O4U

The problem does not seem to be directly related to dirt/residue. I recently stripped it down to the frame and cleaned everything well. It ran ok well for about a hundred rounds after that but then started to hang up again. I've also replicated the problem with the original 10" barrel - shown in the video. So it doesn't seem to be related to the receiver. When I did the complete stripdown, I did notice some "unusual" wear on the right front edge of the hammer, on the disconnector lever, and on the bottom of the bolt. Pictures are posted below.

The wear is obviously a sign of some rubbing or friction. With the receiver removed, the hammer swings freely. Any help you can offer to figure out what caused this and how to correct/fix it would be greatly appreciated.

[bgreenea3]

I would take that Burr off the disconnector and the hammer, thats causing your hang ups...... what caused the burr? for that I'm at a loss maybe a photo of your pac-lite and bolt could help.

[Bullseye]

What kind of ammo are we shooting? Any Hyper velocity stuff? Stingers or Zappers?

You can dress that disconnector and remove that burr from the side. I'd also chamfer (dress) the edge of the hammer with a 45° bevel along the worn edge. It appears as if the bolt is being driven against the disconnector causing the damage to the edge. I'd keep an eye on it to prevent any out-of-battery detonations. Can you measure the width of that hammer for me? It seems to appear a little wider than the OEM versions and this could cause some of the wear you've depicted.

R,
Bullseye

[mwwilkew]

No stinger or hyper velocity ammo has been used. 99% has been federal 525 bulk pack. I'll get a hammer width this evening.

[blue68f100]

Have you confirmed the disconnector is FLAT. I had one that got warped somehow. I just laid it on an anvil and flattened it back out. The problem never came back. It think it was related to the barrel/receiver was not align properly when I installed it.

How much side play is in the Hammer/bushing/pin? There should be hardly any with the VQ parts. If this is the case the Disconnector may be warped.

[mwwilkew]

The VQ hammer in the pictures measures 0.262" with my digital calipers. I've measured the original OEM that was in the pistol and also the hammer on my MkIII 22/45. They both measure 0.272".

I've removed the disconnector burr and cleaned up the hammer as suggested. The disconnector is flat (in fact if you search, a twisted disconnector was the source of my first problems with this pistol). There is very little side-to-side play in the hammer/bushing/pin.

The pistol seems to be functioning better but I'll have to get it out to the range to really test it. Hopefully the cause of malfunctioning has been corrected.

As for the cause, I'm wondering if blue is on to something. The original 10" barrel has very little rotational play when you put the barrel on the frame. The Tac-Lite barrel has quite a bit of rotational play and it has been a pain a few times to get it oriented correctly. Could the damage seen have been caused by a receiver/barrel put on at a slight cant? This doesn't seem possible because it has to be oriented correctly to insert the bolt stop pin.

Let me know if you really think it would help to see pictures of the Pac-Lite receiver and I'll get it done.

[bgreenea3]

If you have a lot of play in the frame to reciever you can put a shim (beverage can works) by the lug to tighten it up. It also will keep crud out of the trigger parts.

the fit can loosen over time especially if the pistol gets taken apart a lot.

if that doesn't work maybe your pac-lite is out of spec. tac sol should take care of it if it is.

[blue68f100]

mwwilkew, The barrel/receiver can be mounted at a slight angle, the hole in the frame is large enough for that on my MKIII. I do not know if the paclite's body is hard enough to wear the disconnector.

[piasashooter]

I agree with the above posts that the barre/receiver could be rotated slightly when fully installed. I know on my MKIII it can be rotated a fair amout, but the bolt stop pin portion of the mainspring centers the receiver back up when installed. If the bolt stop pin holes in the after market receiver are larger than on a factory unit, it could still be rotated to much when assembled. I would try to measure the diameter of the holes in the Ruger receiver, and compare them to the holes in the after market one.

[mwwilkew]

There is not alot of slop or play in the fit of either the TS Pac-Lite or Ruger receiver to the barrel. The "play" I've tried to desribe seems to be a result of a wider slot that accepts the frame lug. When I just set the Ruger receiver on the frame (w/o tapping it into place) there is very little rotational play. It seems the width of the lug fills the slot. When I set the TS receiver on the frame there is a lot of play. I can rotate the receiver about 5 degrees either way. Maybe this is because the TS receiver is made to fit on both Mk II/III and 22/45 frames?

The Pac-Lite receiver is an aluminum with an inserted steel barrel. I don't think it could have caused the damage to the disconnector. Seems the bolt is more likely but I don't know the workings well enough to confirm this. The burr was flat on top as if the bolt was riding on it incorrectly or off-center, which seems to match the theory that the barrel was installed at a slight angle.

I'll compare/measure the Pac-Lite and Ruger bolt stop pin holes this evening.

THANKS FOR ALL THE HELP.

[mwwilkew]

The bolt stop pin holes on the Pac-Lite, MkII 10", and MkIII 22/45 all measure about 0.316" +/- a thousandth or two. So that doesn't seem to be an issue. FYI - Bolt stop pin measures 0.306" in diameter.

But, as you can see in the picture, there's a big difference in the slot that accepts the frame lug. MkII on the left / Pac-Lite on the right.


The slot widths measure as follows:
MkII 10" = 0.380"
MkIII 22/45 = 0.410
Pac-Lite = 0.500

[greener]

If you have a lot of play in the frame to reciever you can put a shim (beverage can works) by the lug to tighten it up. It also will keep crud out of the trigger parts.

the fit can loosen over time especially if the pistol gets taken apart a lot.

if that doesn't work maybe your pac-lite is out of spec. tac sol should take care of it if it is.

I'd also give the blast shield/shim a try. Takes a couple minutes to make/install.

[Bullseye]

Your hammer dimensions are within specs it only looked wider because of the photo. Based upon what I can see it appears that your hammer and bolt are not centered above one another properly. The same applies to your disconnector. That dent is actually the edge of the bolt. The disconnector is supposed to be centered over the relief cut-out of the bolt. When the bolt retracts should ride along the top edge of the disconnector bar. Yours is slightly off center. This condition appears to be the bolt is misaligned in the receiver tube in relation to the frame. The hammer's right edge is rubbing along the inside of the bolt track causing the scrape marks. The hammer should be mainly centered and the hammer face resting along the center ridge of the underside of the bolt. It is hard to see if the receiver is not oriented correctly. What you can to do to relieve this problem is take approximately .010" to .020" off of your hammer bushing on the narrow end (the side closest to the thumb safety). This will allow your hammer to naturally move within the frame to the left and reduce the drag. If the bushing is not all the way against the thumb safety then you may have to file the head of your hammer strut rivet down the .010" to .020" to allow for the hammer's movement, or a combination of both of these things to support hammer movement. This will relive the pressure on the right side of the bolt by the hammer.

R,
Bullseye

[mwwilkew]

I thought I'd start by replacing the VQ hammer/Clark bushing with the original Ruger hammer and bushing. I figured that out to get things aligned correctly and confirm if the Clark bushing is throwing things out of alignment. Everything seems to function ok but I won't really know until I get out to the range sometime this weekend.

But...

After removing the VQ hammer I noticed that the hammer spur does not swing freely on the rivet. I don't see any burrs on or the hammer, hammer spur, or hammer spur rivet, but it is definitely hanging up on something. Seems like this would certainly interfere with functioning.

I'll update with a range report soon.

[mwwilkew]

I've been to the range twice now after replacing the VQ Hammer and Clark Hammer Bushing with the original Ruger parts. I did not clean the pistol before heading out.

I'm happy to report that I did not have a single FTE or FTF while shooting both Federal bulk pack and CCI SV ammo. The bolt seems to cycle forward easily, as it should. So...I'll attribute the cycling problems to an off-center hammer likely due to the clark bushing (Bullseye's assessment). If I ever get around to filing the clark bushing I'll post another update for final confirmation.

Thanks again to all for your help figuring this one out.