Modified long first stage trigger
Greetings all! Been lurking around here for a few days. Came to this forum after a “referral” from AGN where “miscreants” like you seem to be a popular topic. :butkick: But I came with an idea that I want to run through here before I attempt myself, as I am not that smart. That’s why I think I am in good company here :8:
Snowed in here in DC and did some messing around with my brand new Vulcan .25 Gen2. Switched the bolt to the right, that was easy. Tried to add as long travel as I could to the first stage trigger, but it turned out to be very difficult and spent hours on it…the gun would either not cock or went off even with the safety still on. I read the posts here and Ernest Rowe’s video and Sniperqty too. Ended up compromising for safety and with very little first stage travel. However, I got to think… If there is just about a 1/8 inch slack I could add to the trigger pull rod, it should be enough.
So looking at the rear threaded turn-buckle right where the rod’s threaded end comes out to the rear, I am thinking about removing about 1/8in from the threads and making the rod smooth there. There still would be threads left towards the rod’s end but the entire rod would have a 1/8 inch smooth slack that can move within the turnbuckle without resistance. When I pull the first stage, the smooth 1/8 inch section of the rod slides forward inside the threaded turn-buckle until the threaded section of the rod engages the threaded section of the turn-buckle and pulls on the rear trigger assembly. See photo (I need to move out the threads first a bit more by unscrewing the front buckle more near the main trigger). What do you think? The rear trigger assembly is self-contained with its own spring tension so it will not move around with the slack in the long trigger rod. And the long rod is still under some spring tension from the collar/spring combo.
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The second video shows the long first stage pull in action…
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Modified the first stage pull that I think was too short and unpredictable. I followed Rowe’s video as well as the guides posted on this forum, but I must be too stupid because was never able to get a decent and pronounced first stage while having a good hair-trigger also. One or the other was compromised, at times to the point of safety. So I figured I need to add a little slack in the linkage. Per advice I didn’t want to mess up the factory setup.
The factory pull rod I measured at 3mm diameter. At my local RC model hobby shop I bought a servo-push/pull rod that had a threaded metal buckle with a 3/32in or little over 2mm diameter and the rest of it was smooth. Also bought some 3/32in collars with setscrews.
Removed the entire 3mm factory trigger-rod from the trigger itself and the rear trigger assembly by undoing the front and rear buckles. Unscrewed the factory rod from the rear trigger assembly buckle. Now took the new 3/32OD rod and pushed back on it the original tension spring and three 3/32ID collars with the set screws (two needed but I added one more for extra measure) Then made sure I have enough thread on the new rod buckle to go either way and snapped the buckle in place on the trigger. Next, cut the rod down to size and slipped it inside the 3mm rear buckle where it can move back and forth without any resistance. Then bent the end of the rod 90 degrees (I recommend a sharp 90 so there is no slack later in the pull). Need to make sure you have some play, mine is about 1/8 in just by guessing. You can adjust this later by turning the rod left or right inside the threaded end at the trigger.
Set the spring tension on the new rod with one of the collars, just like the factory one was set. This will give the first stage trigger tension, but also keeps the trigger always forward now that the rear is not threaded anymore. Next I cocked the rifle, put the trigger on safe and made sure the trigger is sitting flush with the safety plate without any slack in the trigger when pulled. While holding it flush I pushed one of the collars towards the rear until it was flush against the rear turnbuckle stem. Secured it with the setscrew. if you take it off safety, based on how much slack you had setup earlier, the rod should be able to slide forward as you pull the trigger during the first stage, and when the 90 degree bend catches on the turn-buckle it engages the second stage of the trigger. May need to adjust that first stage slack to what you like. Because of the extra pull-slack added and because the pull rod is not threaded, the rear trigger-assembly is now isolated from the rod linkage until ready to pull the second stage. Also, now I can adjust the second stage as a hair-trigger without worrying about rendering the safety null, or not being able to slide the safety-plate under the trigger anymore because of the rigid short factory first stage travel.
Do it at your own risk. Let me know if I screwed up any of the steps.
Couple of videos:
[video src="http://vid1124.photobucket.com/albums/l575/tomsz2007/File_000_zps6egzmftm.mp4" /]
[video src="http://vid1124.photobucket.com/albums/l575/tomsz2007/File_001_zpss8vcgwza.mp4" /]
Yes, will try to make it where it can go back stock, will try with another linkage.
need to play with it a bit more. don’t mod it the way it is irreversible that is my advice.
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With the first stage trigger now not directly connected to the rear trigger assembly during the entire first stage travel, now I was able to set the second stage trigger for less trigger blades overlap…as required for a hair trigger. I will try to measure the trigger-pull for both stages when I get a chance. Lacking a pull-gauge, I read somewhere that they used a balloon and filled it with water slowly and measured the final weight at the point the trigger went off.
One thing I know that if not for the original tension spring, the first stage trigger pull would be zero. But, of course it needs to be a tension spring over there because the rod is now not threaded in the rear buckle anymore and instead it slides in it now. So for the trigger to stay forward cocked there must be tension. This spring can be any strength, but I am ok with the factory tension spring, I have it set at the minimum point needed to keep the trigger pushed forward.