Homebrew Crosman trigger 2-stage conversion
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Homebrew Crosman trigger 2-stage conversion
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Topic: Homebrew Crosman trigger 2-stage conversion (Read 2573 times))
Sdparks
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Homebrew Crosman trigger 2-stage conversion
«
on:
December 01, 2012, 10:00:40 PM »
During my recent self-tune of my Remington Vantage 1200, I made my own mods to the trigger blade to make it actually a two-stage pull, as opposed to the faux two-stage that Crosman advertises.
The two-stage effect is achieved by having two different sets of lever lengths acting between the trigger blade and bottom sear. So, instead of just the fat pin in the trigger blade pushing on the bottom sear for the entire pull, at first there is another contact point closer to the pivot point on the trigger blade for most of the pull, then the fat pin contacts the bottom sear just before the top sear is released.
I would have like to have tapped a hole for a screw so the the first stage would have been adjustable, but drilling the hole in the blade would have been difficult (at least with my equipment and skills). So, I filled up the inside of the trigger blade with epoxy, then drilled a hole in that and inserted a pin. I adjusted the first stage by packing little bits of aluminum foil in the bottom of the hole until the transition point was right. I thought this would have been very tedious, but I got the right setup in just a few tries.
Steps:
1. Prep: I waxed the fat pin and wrapped the pivot pin in non-stick aluminum foil to prevent the epoxy from bonding to them. I wrapped the trigger with tape to create a reservoir for the epoxy.
2. Fill: I filled the inside of the blade with JB Weld to about half way up the pin holes. Let cure per directions.
3. Trim: Remove the tape and pins and trim up. The epoxy at the front of the blade had to be cut back some to clear the bottom sear.
4. Drill: I drilled a hole the diameter of the new post about half way between the fat pin and pivot pin, maybe a little closer to the pivot pin.
5. Install post: I made a post out of a section of tool steel rod, but you could use the shaft of a broken drill bit. Grind the tip round and smooth off. I could have hardened the post and polished the tip, but I didn't.
6. Adjust. The height of the post has to be adjusted so that the fat pin engages the bottom sear a safe distance before the sear releases. Also, if the post is too tall, the total amount of sear engagement will be reduced, which isn't what you want to achieve.
Please note that I took the trigger assembly apart and studied it carefully until I understood it well before attempting this mod. This isn't a mod that you should take on casually. Obviously, you could end up with a dangerous gun if this isn't done correctly. If you aren't comfortable doing this yourself, just buy a replacement trigger blade and be done with it.
In addition, I left out the trigger return spring and polished the important engagement surfaces. The result is a pretty good trigger. At first I thought I had really screwed things up, because if I partially pulled the trigger and let it go, the trigger would not return; it would just stay where it was or flop forward if the gun was pointed down. I later read the excellent post on balk firing, and realized that I didn't mess up the trigger, but just made it obvious when the trigger was partially released. Without the gun cocked, the two-stage effect is very pronounced, but somewhat less so when cocked and there is a lot more friction that you have to pull through. If I squeeze the trigger quickly, I can just pull right through the second stage, but with a reasonably controlled squeeze, the second stage is pretty easy to detect and use for a well-timed release. The ergonomics of the trigger is still what it is, and it is really too long a reach for my liking, but for a cheap fix on a cheap gun, I'm pretty happy with the result, and I enjoyed the challenge.
I didn't do anything to address the overtravel after release, but that would be another big improvement. I have an idea, but if anyone has a proven solution, please share.
Below are some photos of the process.
«
Last Edit: December 01, 2012, 10:05:00 PM by Sdparks
»
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Erevojoe
Shoot twice, measure once
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Posts: 254
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Real Name: Joseph
Re: Homebrew Crosman trigger 2-stage conversion
«
Reply #1 on:
December 02, 2012, 02:09:57 PM »
Very interesting, thanks. I just made a bushing for the fat pin and polished all the contact points and it made a huge improvement. I don't make home brew recommendations so I won't detail that sawing off the tip of a standard air hose quick connect makes the perfect fat pin bushing. You just have to cut it to fit inside the trigger or file it down afterwards. Inside diameter is just right and outside diameter seams to great. Still better to buy the tuna if you can. If you can't afford that, I surly don't recommend spending a buck on a male quick connect and a few seconds sawing off the tip.
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Columbiana, Al
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uncle paulie
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Real Name: Paul
Re: Homebrew Crosman trigger 2-stage conversion
«
Reply #2 on:
December 03, 2012, 09:19:18 AM »
Quote from OP:
Please note that I took the trigger assembly apart and studied it carefully until I understood it well before attempting this mod. This isn't a mod that you should take on casually. Obviously, you could end up with a dangerous gun if this isn't done correctly. If you aren't comfortable doing this yourself, just buy a replacement trigger blade and be done with it.
Personally, I love to get into things to either see what makes them tick or to improve. But I always determine the validity of a modification against the cost of existing solutions for any problem. CDT has a proven solution for the trigger issues which is really too cheap. $33 and 10 minutes of your time solves this dilemma and is absolutely safe if installed properly according to directions. For me, the time required to produce these types of mods and the potential safety issues presented would put this mod in the category of "Poor Return on Investment" as I would spend far less time earning the money to buy it than to make it. JMHO
pv
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ezman604
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Real Name: Dave - DEz
Re: Homebrew Crosman trigger 2-stage conversion
«
Reply #3 on:
December 03, 2012, 09:53:02 AM »
Agree with Paul on the CDT trigger and the benefit versus investment in time and money. The GRT-III is by far the best, easiest and fastest way to improve ANY trigger that it is compatible with. But, being a tinkerer myself, it's not all about ROI but more about doing something yourself and seeing the improvements. And enjoying the fruit of your labor.
Excellent job and great results. Just also keep in mind OP and all that any modifications in the trigger group area is very critical and can render a gun dangerous to you and others. BE VERY CAREFUL when working on the trigger group!!!! The described modification can not and should not be attempted by MOST folks. It should only be attempted by those with the experience, tools and abilities to make such a modification.
SAFE & Happy Shooting!!!!
Dave
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Onebaddj
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Posts: 4562
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Re: Homebrew Crosman trigger 2-stage conversion
«
Reply #4 on:
December 04, 2012, 08:28:52 PM »
Nice work on the trigger. Im a tinkerer that cant leave things alone either. If i can build it i will sometimes the satisfaction of a job well done is worth the cost of doing the job.
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Homebrew Crosman trigger 2-stage conversion