RUGER Mark, Trigger Pre-travel Mod Delta - DIY Project

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Bullseye
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RUGER Mark, Trigger Pre-travel Mod Delta - DIY Project

Post by Bullseye » Wed Aug 17, 2005 3:40 am

For RUGER, Mark I/II/III pistols
Trigger pre-travel screw installation, Mod Delta – DIY Project
By Bullseye and Deltan 1844

Another Mark II.org forum member came up with a good design making the pre-travel screw accessible to the outside of the pistol by drilling through the trigger face on an angle. From now on I will refer to this as the pre-travel screw mod "Delta," in honor of the forum member who suggested it - Deltan 1844.

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(*) Used with permission of Deltan 1844

Here's another version of the Delta mod in a standard stock Ruger trigger submitted by another of our members - Perazzi.

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I made a three of these triggers today with the external pre-travel adjustment. I really liked the speed at which I can adjust out the excessive trigger take-up using this method. Although the trigger pre-travel adjustment is generally a one-time adjustment, having the screw externally accessible is a huge time saver for getting the amount of pre-travel right in the Ruger pistol.

I used some of the VQ bargain bin triggers and they turned out just fine. I tapped two triggers for pre-travel adjustments using 4-40 set screws and one with a 6-32 set screw. I like the 6-32 size the best for this kind of external adjustment. The 4-40 tap is just a little too flimsy for tapping threads at such a steep angle and there's a real good chance of breaking one with this small of a hole. The 6-32 set screw sticks out of the hole a little more than the 4-40, but the pre-travel adjustment is so high up on the trigger face that the set screw sticking out a little is no problem for the trigger feel.

Image
(*) Used with permission of Deltan 1844

I drilled two of these triggers using the milling machine and the other one using a drill press. Both drilling set ups had ultra solid drill vises and adjustable table positioning. I also used a center point cutter to set up the hole for drilling with each machine. Using the center point cutter was very stable and gave me a nice solid deep starting point hole for the drill bit - no bit walking. I didn't have any of the run-out issues with my drill press that Deltan 1844 had mentioned when he did his trigger modification; the drill press I have is a high-end Rockwell.

If someone takes their time and has a real good starter hole, then this isn't a very difficult modification to undertake. However, if one gets in a hurry, then a broken tap or a missed drilled hole will result in a ruined trigger. I used .180" up and .180" across for the center point of my set screw holes. The drill angle is approximately 45 degrees relative to the trigger mount face.

The Ruger factory trigger can also be modified with this procedure. The factory trigger is made of a softer metal which facilitates drilling and tapping much easier.

Here's a look at the final product.

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Good luck.

R,
Bullseye
Last edited by Bullseye on Sat Sep 17, 2011 5:47 pm, edited 2 times in total.
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Ayms Pourly
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Pre-travel Mod Delta

Post by Ayms Pourly » Sat Aug 27, 2005 10:17 pm

Bullseye,

This workshop section has been very informative. Thank you. Do you have any tricks up your sleeve for pre-travel and or over-travel screws for the 10/22?

Thanks Again,
Ayms

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Post by Bullseye » Sat Aug 27, 2005 10:22 pm

Welcome Ayms! I like your play on words for your board name.

I hadn't given the 10/22 a thought. There seemed like so many aftermarket things were already out there for it. I'll have to give it a look and see what I can come up with.

R,
Bullseye

What's next - Kenardly Chute
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