Ruger Mk III trigger pull

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Ruger Mk III trigger pull

Postby markIIIronp » Fri Jan 04, 2008 4:14 pm

Can I successfully decrease my trigger pull on a MK III 10/45 by reworking the original factory parts? I do not really want to spend the $100 or more for an accurizing kit. I disassembled the pistol, using bullseye on-line instructions, which by the way were excellent, and polished the seer, hammer and disconector lever. This made for a smoother trigger pull, but still measured 4 lbs on a gauge. I took it apart a second and used a fine stone on the hammer where it lays against the seer and repolished the area. I now have a 3.8 lb. pull. Can I continue this process safely until I wind up with the desired 2.5 lb pull?

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Re: Ruer Mk III trigger pull

Postby wlambert » Fri Jan 04, 2008 5:45 pm

markIIIronp wrote:Can I successfully decrease my trigger pull on a MK III 10/45 by reworking the original factory parts? I do not really want to spend the $100 or more for an accurizing kit. I disassembled the pistol, using bullseye on-line instructions, which by the way were excellent, and polished the seer, hammer and disconector lever. This made for a smoother trigger pull, but still measured 4 lbs on a gauge. I took it apart a second and used a fine stone on the hammer where it lays against the seer and repolished the area. I now have a 3.8 lb. pull. Can I continue this process safely until I wind up with the desired 2.5 lb pull?


If you continue stoning on the hammer and sear without the proper equipment you will likely end up with a pistol that is unsafe.

There are probably three ways to go:

1. Buy a jig and learn how to use it.
2. Buy the accurizing kit.
3. Allow a gun smith to do it right.

I got the accurizing kit. Still too much creep. They I took it to a gun smith and had a proper job done for less than the cost of the kit. If I had it to do over again, I would just take it to a good smith.

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Postby Bullseye » Fri Jan 04, 2008 7:31 pm

No! The least polishing/stoning friendly component on a Ruger .22 Autopistol is the hammer. Replacing the the sear with a target one from VQ costs around $20. Typically this is the only part that needs replacing in a Ruger Mark pistol to improve the trigger feel.

The investment in Jigs and stones and the myriad of miscut sears and hammers practicing to hone them correctly cost far more than replacing one or two parts. If you're not planning on performing trigger jobs for a living then the expense does not justify the outcome. What's even worse is the possibility that yourself, or someone nearby, could be seriously injured by an imperfect trigger job. Maybe not now, but some time later when the caution has faded away and you least expect a failure.

Lots of engineering has gone into producing user drop-in parts that can be installed in a variety of pistols, all with slightly different manufacturing tolerances, with 100% safely.

Sorry for the bluntness of this response but safety is not something to mess with when working on firearms. I toss many parts that seem fine but upon close inspection have been tweaked out of tolerances by someone who meant well but naively worked it out of specs.


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Postby markIIIronp » Sat Jan 05, 2008 1:37 am

Thanks for the good advice. I will cease the stoning and polishing and save up for a proper trigger job or parts.

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Postby markIIIronp » Sat Jan 05, 2008 9:52 am

Bullseye,
Question:
I am curious, why do I not need the hammer that comes in the VQ kit, as this appears to contain the ground step that releases from the seer, thus reducing trigger pull? Am I confused as to how the trigger operates? :?: :shock:

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Postby Bullseye » Sat Jan 05, 2008 2:02 pm

Well, the trigger operates on the sear releasing the hammer hook when activated by the trigger bar/disconnector lever. The sear and the hammer have precise engagement angles cut into their contact surfaces. It's this engagement angle that keeps the sear on the hammers hook (or the ground step you were referring to earlier).

Here's a link to an animation I made showing the Ruger's trigger operation. http://www.guntalk-online.com/detailstrip.htm#operate The blue part is the sear and the black one is the hammer. There are two animations; one for Mark III and the other for Mark II pistols.

The factory sear is cut with the engagement angle slightly over level. This angle makes the trigger weight feel a little heavier. A VQ sear has the sear engagement surface at a more level angle and this causes the trigger pull to feel lighter. The problem is if the engagement angles are changed by non-precise means the angle can be one where the sear can slip off of the hammer's hook without activation from the trigger - thus causing an unintentional discharge. There doesn't have to be very much angular difference to totally ruin the hammer and sear's engagement angle and create an unsafe pistol.

The engagement angle on the VQ hammer is basically the same as the factory one. It's the VQ target sear that has the angle cut for trigger weight reduction. This is why the sear is the part to replace with a VQ one and the hammer doesn't usually have to be changed from the factory part.

The VQ target hammer is lighter than the factory hammer and in some pistols the lighter hammer causes detonation problems.

Since your hammer has now been altered by polishing, it may be a good idea to replace it with a VQ one when you change out the sear.

I hope this description plus the animation helps you understand the trigger's operation better.

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Postby markIIIronp » Sat Jan 05, 2008 5:50 pm

Thanks Bullseye you are very good at explaining the inner workings. I understand completly now how the seer and trigger work. :D

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Postby madcratebuilder » Sun Jan 06, 2008 10:13 am

markIIIronp wrote:Thanks Bullseye you are very good at explaining the inner workings. I understand completely now how the seer and trigger work. :D


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Postby greener » Sun Jan 06, 2008 11:26 am

I've done the VQ trigger/hammer/sear upgrade on my MKIII Hunter and the VQ trigger/sear upgrade on my 22/45. Any differences in feel are barely noticeable. The result has been two pistols with light, crisp triggers from an easy, drop in fix. For $20-$100, this fix was much better than me trying to develop the skills needed to reproduce VQ's work.

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Postby markIIIronp » Sat Jan 12, 2008 11:26 pm

Well, I orderd a VQ accurizing kit for my Mark III 22/45. Decided to get the whole kit after I found it on the internet for less tha $90. If you remember I had polished my hammer and seer and got the pull down to 4 pounds. While I was waiting for the kit to arrive, I decided to use Bullseye's excellent instructions and perform the DIY mag safety removal. That worked out beautiflly and guess what? After replacing the mag disconnector and spring and replacing with the two #10 washers, I now have a real smooth trigger with a 3 pound pull. Can't wait to take it to the range and try it out. I will still install the new VQ kit when it arrives, but I will also have a very good backup trigger if I need it. :D

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Postby Bullseye » Sat Jan 12, 2008 11:32 pm

Great news! Having a smooth trigger makes a huge difference in accuracy and confidence in your pistol.

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Mag safety removal

Postby markIIIronp » Tue Jan 15, 2008 11:28 am

Bullseye,
I took my pistol to the range last night. It would only fire the first shot. The trigger would not reset. I had to eject the bullet in the chamber and the next one would fire. I did this with a couple of clips. It would not fire two in a row. One I was able to feel the trigger reset after pulling open the bolt about a ¼ inch. I think the outer washer I used to replace the mag safety lever was hanging up the seer. When I filed this washer down to 7/16 diameter, it appeared that it would interfere with the seer, so I filed it down to about .400 inch diameter. This did not seem to small to interfere with the seer disconnector lever. Could .400 inch diameter still be too large or do I have another problem?

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Postby markIIIronp » Tue Jan 15, 2008 1:07 pm

Cocked and dry-fired the pistol several times in different positions. Trigger seems to be resetting without firing ammo. Field stripped and I noticed that the hammer has lateral motion of about 0.050 of an inch. The inner washer seems to be staying in the timing flat that was the first cut on the washer. The 0.050 inch movement seems excessive. The only part out of the loop and not compensated for by the two #10 washers is the mag safety lever spring. I wish I would have had more time to test it at the range last night. I had to borrow a pistol to shoot a bullseye match and didn't have time to do more testing after the match. Do you have an idea of what my problem might be?

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Postby Bullseye » Tue Jan 15, 2008 9:52 pm

One possibility is the pretravel screw setting is just a little too close. This would be especially true if you adjusted it for the VQ kit installation and then installed the washer mod. You might have to back out the pretravel screw just a little. If your inner washer is indexing correctly then it shouldn't be interfering with the hammer and sear resetting.

Another possibility is the outer washer diameter is too small and the disconnector is hanging up on it. The squared hole may be contacting the edge of the outer washer and not moving upward smoothly. Also, check for any burrs that may impart friction here and prevent the disconnector lever from rising smoothly.

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Postby markIIIronp » Fri Feb 08, 2008 1:49 am

Remade the two #10 washers a few different times. Filed the outside washer to .440" diameter, test fired, filed to .438" diameter, test fired, filed to .437" diameter and test fired. Was not able to fire 2-10 round clips without the trigger hanging up and not resetting. The side slop in the hammer always bothered me. A couple of days ago I went to the hardware store and purchased a 1/4" copper washer. I filed the diameter to .438". Instead of installing the inner washer with the filed flats, I left it out and instead took a piece of spring material and coiled it around the shank of a 5/16" drill bit. I cut of the access and was left with about one and one half coils. This took out most of the side play in the hammer. I now have a real smooth trigger with a little less than a 3# pull. I went to the range and shot 200 rounds without any jams or problems with the trigger not resetting. I think my whole problem was the hole in the #10 washers was too tight on the hammer sleeve and the excessive side travel in the hammer.


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