openclassterror Posted March 1, 2014 Share Posted March 1, 2014 (edited) Hi all- I have been playing around with this for a while trying to come up with an easy plan. Here are some pictures, and I will explain as best I can. You will need- 1- #6-40 x 3/16 socket set screw 1- #4-40 x 3/8 socket set screw 1- #6-32 x 3/8 socket set screw 5/64 Allen wrench .050 Allen wrench #43 drill, and #4-40 tap #33 drill, and #6-40 tap #36 drill, and #6-32 tap Cobalt drills recommended, as trigger is somewhat hard. Spiral point, NOT spiral flute, TiN, or TiALN coated taps recommended. Quality tapping fluid, also used while drilling. 1.- I drilled and tapped a #6-40 hole through the tab at the rear of the trigger. This set screw bears against a cross pin in the trigger group. As you turn the screw the trigger will advance, reducing engagement. Keep in mind that advancing the trigger will prevent the safety from operating unless you grind a small amount off the rounded tab behing the trigger that bears against the safety. DO NOT GRIND TOO MUCH here or the safety will cease to operate and you will need a new trigger! Baby steps here, take a little at a time as you advance the trigger. 2.- I also drilled and tapped a #4-40 screw at an angle underneath the disconnector, allowing the distance between the hooks to be adjusted. This is important because if you advance the trigger, the disconnector also moves forward, and cannot reset far enough to release the hammer back onto the primary sear. Unfortunately, the trigger must be out of the housing to turn this screw, so you have to make a minor adjustment, then reinstall to check. I am working on a replacement disconnector which has a small tab added to it under the nose. This will allow a VERTICAL adjustment screw to be used, which is accessed through the trigger guard with the unit assembled. It will also be USA made, so in conjunction with a replacement follower will comply with the 922R provisions. Scroll down for more pictures and details. Edited March 1, 2014 by openclassterror Link to comment Share on other sites More sharing options...
openclassterror Posted March 1, 2014 Author Share Posted March 1, 2014 (edited) Here is a picture of the trigger along side the housing so you can see the pin that the engagement screw bears against. You can also see the tab that bears against the safety. Edited March 1, 2014 by openclassterror Link to comment Share on other sites More sharing options...
openclassterror Posted March 1, 2014 Author Share Posted March 1, 2014 (edited) Here the trigger is installed to show relationship of overtravel screw. I used a #6-32 screw, and stopped tapping just before the tapered end of the tap went completely through. This keeps the threads tight and prevents the screw from backing out. Adjustment- Make sure all screws are clean and degreased, and use Blue Loctite on both trigger screws. The overtravel screw in the plastic trigger guard does not need Loctite. 1- Overtravel- Run screw in from back of trigger guard until trigger will not release the hammer. Keep tension on the trigger and restrain the hammer, then slowly back off the screw until hammer is released. Go an additional 1/4 turn for clearance. 2- Engagement- Re-cock the hammer. Turn vertical screw at rear of trigger in until hammer is released, while restraining the hammer to prevent damage. Back off 1/2 turn. Your safety will no longer function. You will have to carefully grind the tab behind the trigger a little at a time until safety will just engage and not allow ANY trigger movement with the hammer cocked. 3- Disconnector- This is tough with the factory disconnector. At this point, the disconnector may not let go of the hammer when the trigger is released. You will have to remove the trigger/ disconnector assembly from the housing, and advance the #4-40 screw until the disconnector starts to move away from its stop notch on the top of the trigger. The ideal setting is achieved when the hammer rubs on the disconnector as it is cocked, but does not quite catch. Once we have the new disconnector, this screw will be visible on the underside of the trigger inside the trigger guard, and adjustment will be MUCH easier, as it can be done with the unit assembled. Please ask questions if the instructions are not clear enough! Tom Edited March 1, 2014 by openclassterror Link to comment Share on other sites More sharing options...
mikeAZ Posted March 1, 2014 Share Posted March 1, 2014 (edited) Sign me up!!! Any idea when you will have your disconnector available? May as well be "compliant"... Edited March 1, 2014 by mike NM Link to comment Share on other sites More sharing options...
Steve RA Posted March 1, 2014 Share Posted March 1, 2014 You might consider working up a price for people to send their trigger group in and have the work done ??? Link to comment Share on other sites More sharing options...
mertbl Posted March 2, 2014 Share Posted March 2, 2014 You might consider working up a price for people to send their trigger group in and have the work done ??? This. All day. Seems simple but still more than what I'm comfortable doing. If you offered the disconnecter and trigger pre drilled I'd buy one. Link to comment Share on other sites More sharing options...
spankymac Posted March 2, 2014 Share Posted March 2, 2014 You might consider working up a price for people to send their trigger group in and have the work done ??? This. All day. Seems simple but still more than what I'm comfortable doing. If you offered the disconnecter and trigger pre drilled I'd buy one. +1 Link to comment Share on other sites More sharing options...
openclassterror Posted March 2, 2014 Author Share Posted March 2, 2014 Might do that. I am even thinking about getting a few trigger groups from Stoeger if they will sell them to me, doing all the mods and then selling them on a core exchange basis so people aren't without their guns functioning for any length of time. But that is not the point of this thread. This thread is for people who feel up to the task themselves, so they can see what is involved at a detailed level. If I was only trying to sell the service, I don't think I would have shown the world how to do it! Using the process as shown, I got mine down to a crisp 4.7 lbs, and total trigger movement down to .050 inch. A MAJOR improvement over the 8+ lbs it scaled when I got it. Link to comment Share on other sites More sharing options...
mertbl Posted March 2, 2014 Share Posted March 2, 2014 .050 inch? Is that a typo? Link to comment Share on other sites More sharing options...
Steve RA Posted March 2, 2014 Share Posted March 2, 2014 Personally, I'd just as soon pay to have it done as I don't have all the tools required, and probably would not use them for anything else. Link to comment Share on other sites More sharing options...
mpom Posted March 2, 2014 Share Posted March 2, 2014 .050 inch? Is that a typo? I can believe it. Reduced engagement and adjusted overtravel in my JM930 and would estimate its down to this as well, excluding short takeup, which measures ounces. Link to comment Share on other sites More sharing options...
openclassterror Posted March 2, 2014 Author Share Posted March 2, 2014 (edited) After further adjustment and range testing, I was able to adjust trigger down to .024 inch travel, measured at the middle of the trigger shoe in front of the stop. Picture shows trigger in cocked position. Measured between stop and trigger with feeler gage. It gave positive reset and no doubles. It is nearly as crisp as some aftermarket AR triggers. Tom Edited March 2, 2014 by openclassterror Link to comment Share on other sites More sharing options...
TitoR Posted March 2, 2014 Share Posted March 2, 2014 .050 inch? Is that a typo?I can believe it. Reduced engagement and adjusted overtravel in my JM930 and would estimate its down to this as well, excluding short takeup, which measures ounces. Mpom, can you describe how you made the modifications to the JM930 trigger? My trigger is not terrible, but if it can be improved, why not. Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
mpom Posted March 3, 2014 Share Posted March 3, 2014 .050 inch? Is that a typo?I can believe it. Reduced engagement and adjusted overtravel in my JM930 and would estimate its down to this as well, excluding short takeup, which measures ounces. Mpom, can you describe how you made the modifications to the JM930 trigger? My trigger is not terrible, but if it can be improved, why not. Sent from my iPad using Tapatalk First I polished the contact surfaces of hammer and sear. Then watched interaction between the two as I pulled the trigger with hammer cocked. Clearly too much engagement. Took out hammer and stoned perpendicular to contact surface to reduce engagement. Did this in steps until I could see some movement as sear pulled away from hammer, but could not feel the process in the trigger. Did not stone the hammer contact surface to avoid losing surface hardness. Reset the over travel screw, and checked for hammer stability on sear by banging butt into carpeted floor with safety off. Ended up with a 3.75 lb fairly crisp pull. Still have a light takeup before trigger hits wall for the release, but its like a 1911; super light and no reason to try and eliminate it. Can slip a .021" feeler gauge between over travel screw tip and back of trigger with trigger up to the "wall", total of .054" with trigger fully forward. Reset is obtained by letting trigger forward .021". With the chrome or nickel plating on the sear and hammer, don't expect significant change anytime soon. No change over past year, although have only fired maybe 300 shells and done at least as many dry fires since the work. Would guess pull weight would have been even lower had I kept the original hammer spring rather than the heavier 10/22, but its pretty good for a shotgun. As OpenClass says, better than a lot of AR15s. Now, just need to learn how to shoot the son of a bitch to its potential! Link to comment Share on other sites More sharing options...
Amr Posted March 3, 2014 Share Posted March 3, 2014 Openclass thanks for the shopping list, instructions, and your time and expertise! I am looking forward to this DIY project and greatly appreciate your willingness to share your knowledge and taking the time to write up a step by step procedure. Link to comment Share on other sites More sharing options...
troupe Posted March 3, 2014 Share Posted March 3, 2014 PM sent to Openclassterror. Link to comment Share on other sites More sharing options...
TitoR Posted March 3, 2014 Share Posted March 3, 2014 Mpom, thanks for the adjustment description. Seems straightforward enough. I have a match this weekend, so it is not the right time to mess with what works, but my next DIY project. Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
Jesse Tischauser Posted March 7, 2014 Share Posted March 7, 2014 How do I get the trigger group out? Hmmm maybe this DIY isn't for me. Link to comment Share on other sites More sharing options...
openclassterror Posted March 7, 2014 Author Share Posted March 7, 2014 Well, Jesse- First you have to take the stock off. Then remove the magazine and barrel. All 4 of the tiny screws have to come out of the top of the receiver. Remove the Bolt handle, then the bolt assembly will come out the front of the receiver. At that point you can drive out the vertical pin that retains the carrier latch, and remove that. Next comes the cross-pin in the receiver, which has a big head on one side with a dimple in it. That is NOT the end you hit with the punch. Drive it out, from left to right, and the trigger group will lift forward and out the bottom. It might just fall out if you push in on the carrier release button. Now, if you ignore ALL THAT except the cross pin and pulling it out, you will be good! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now