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  #1  
Old 06-08-2011, 07:16 PM
robmints
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512 Trigger

I'm just hoping to stir some of you experimenters into taking yours apart and making improvements. It would be hard to make it worse.

Take the rifle apart according to the directions and remove this bolt so you can slide the trigger group back:



Slide the trigger group back and remove the magwell:



Continue the slide the TG back and expose this pin:



Push the pin out. I used a nail that I ground the point off that was about .800. It might need a tiny tap but it may just slide:



Slide the TG back in and remove the trigger from the top. Yours will not have that spring hole in it, that was my first attempt to lighten the return. Yours will be hooked under the body of the trigger.:



A couple of mods I made were to lighten the trigger return buy drilling 1/6 hole 3/32 in to try and lighten the pull. I don't think it is a worthwhile change, most of the weight comes from the hook between the trigger and hammer. The hammer spring is heavy and there is a lot of hook. I also put a dab of weld on the trigger to limit the hook engagement to reduce the creep. This is a worthwhile change, creep is reduced but I left it creepier than a target trigger:





To get it back in I found it easier to remove the anti-full auto spring:



Then assemble the trigger back in the TG from the top and retain with the nail to get yourself lined up, chase the nail out with the pin and slide the TG back forward to expose the anti-full auto hook and replace the spring:



Tomorrow will be a try with some polishing of the trigger / hammer engagement area without changing the geometry. It has a pretty good hook and I hope a polish will make the friction easier to overcome but retain the hook.

Just a pic of the target at 50 yards, I was adjusting the scope a little bit to try and get it zeroed in a little better and still got a 88-0x. Pretty good for an rv-7 at 7x and failing light. Well, it seemed pretty good to me. Trigger is better, not good but not terrible anymore either.

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Old 06-10-2011, 04:08 PM
wagon
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Tagged away!

Great post, Rodmints. I always wonder how to remove the TG .... this is a great, the 512 trigger can definitely use some help... and I'll try polishing it if it might help.

Thank you!
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Old 06-10-2011, 05:09 PM
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Laid back a .22wmr today, trigger was checked prior to purchase, actually at least as good as my 511 and Brno 611 so I can cope but I'll be watching for updates.
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Old 06-10-2011, 11:47 PM
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I better tag this one as well.
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Old 06-11-2011, 08:42 AM
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Great pics and this is a thread worth watching - thanks robmints!
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Old 06-11-2011, 07:47 PM
robmints
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Only having time for about 30 rounds before the storm I don't want to jinx the results but, I'm happy as can be. I stayed with what I had, the return spring lightening and the weld up to limit engagement. Then this evening I just polished the contact areas. I'm calling this one done.

We can start back here and slide the TG back, remove the trigger pin, slide the TG back in and pull trigger out the top:



Then slide the whole TG all the way out of the housing and push this pin out, there is no spring tension on it, nothing goes boing:



Here are the parts you have that make up the hammer:



Polish these two areas:





I used the housing as a little cradle to hold the TG as I put it back together and used the chase the nail method with the pin:



It is well worth the time when you end up with a trigger that is nice. IMO this trigger now is better than good. Rico, come give it a try. Sheriff160, you are more than welcome to come shoot it. If you can drill a hole accurately (optional), use a shim and epoxy (or weld it like I did), and can polish metal smooth (I used a felt wheel and a jewelers rouge on a dremel type grinder running slowly) you can have a super nice trigger on your 512. The felt wheel was in a kit I got for $18 at ACE But I did not use the compound in the kit, I had some Walther super fine in my tool box but I'm sure the compound in the kit would do a fine job, just test it on a test piece and make sure you end up with a mirror:

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Old 06-11-2011, 10:01 PM
Sheriff160
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robmints,
As soon as I can get a spare evening, I am going to follow your lead. I'm not looking for real light trigger, just one that isn't as jumpy. I really like the rifle, my 10/22 hasn't come out of the safe since I bought the 512. Outstanding semi auto field rifle.
Thanks for the step by step with pictures.
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Old 06-12-2011, 02:48 AM
rico903
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It is well worth the time when you end up with a trigger that is nice. IMO this trigger now is better than good. Rico, come give it a try. Sheriff160, you are more than welcome to come shoot it. If you can drill a hole accurately (optional), use a shim and epoxy (or weld it like I did), and can polish metal smooth (I used a felt wheel and a jewelers rouge on a dremel type grinder running slowly) you can have a super nice trigger on your 512.

Robmints-looking forward to coming to your range. Afternoons and evenings seem to work best for me.
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  #9  
Old 06-12-2011, 08:13 PM
Sheriff160
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Well, most of you have read my posts that describe my 512 trigger as "jumpy" and with a false release in the pull. I had a feeling there was a machine mark on the surfaces but now that I pulled the trigger group I am sure. Not one tool mark but 3 on the hammer!
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  #10  
Old 06-12-2011, 10:51 PM
Sheriff160
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After about 3 hours of polishing I now have a trigger I am very happy with. I didn't add any material to the trigger to limit travel on mine, yet. My pull now is kinda two stage. I can pull smoooooothly and actually feel when the back of the hammer contacts the disconnector and then stop. From that point, just a tad more pressure and it breaks clean.
I used a dremel tool with a felt wheel and some fine polishing compound to smooth out the tool marks and polish the surfaces until I was pretty satisfied. Then I took a wooden shafted swab and cut all but one inch off the shaft and then chucked it into the dremel. Then I used ScratchX on the swab with the tool set on its lowest RPM and polished up the surfaces like glass. This was definitely worth the effort and really wasn't that hard.

Last edited by Sheriff160; 06-14-2011 at 09:06 PM.
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Old 06-14-2011, 09:05 PM
Sheriff160
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I decided to go back into my trigger group tonight. Like all shade tree tinkerers I have an assortment of boxes of junk and parts that you never throw away cuz you might need it someday. I came across a slightly lighter spring that was almost identical to the trigger spring. All I needed to do was put the 90deg. bend on one end and it was a perfect fit.
What a big difference that made the pull is even smoother and is just a hair under 3 pounds. I am really happy with it now. Because my rifle will see mostly field use, I haven't removed the extra trigger slack (creep), I like the extra safety. However the creep is slicker than an eel and I can feel as soon as the disconnector touches the hammer. From that point, a little pressure and a nice crisp release. No grittyness or resistance in the pull anymore.
Robmints, thanks again for the breakdown pics and the inspiration to get off my butt and get er done!
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Old 02-25-2012, 03:24 PM
paochow
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Thanks to all who put together this guide. I bought a 512 last week and after shooting it today had to do something about the gritty first stage of the trigger. I used this guide to open it up and polish the internals. The first stage is now much much smoother and the trigger is borderline good, would like it a bit lighter though.

I tried doing a spring bend on the return spring a la a TC Encore, but it didn't seem to have much effect. Is the drilling method going to reduce the trigger pull weight much?

Sheriff160 do you recall what type of spring you used to lighten yours?
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Old 01-09-2013, 06:48 PM
aspade
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I went through this over the past two evenings. These pictures were very helpful.

My trigger didn't look too bad but the engagement surface on the hammer had rough machine marks like Sheriff160's all the way up the hook. I cleaned both pieces up with 1600 grit paper wrapped around a 1/8" punch.

I also built up the back of the trigger to 0.250 with JB Weld. Not sure if this will hold up long term but it was what I have.

The verdict: it's still too heavy but the grittyness is gone and the takeup isn't as bad anymore either.

Reassembly was a major PITA for me. I had a lot of trouble keeping the trigger spring (two legged coil) in position on the trigger while dropping it back into the trigger group and then keeping it there while sliding the group back to get the pin back in. I cut a 3/8" section out of a nail as a temporary pin to keep the trigger spring in position on the trigger but it still took me a good 20 minutes to get it right.

Originally I was planning to take it apart again and redo it with 4000 grit paper when I get a chance to buy some, but this was enough of a pain that I'm going to leave well enough alone.

If anyone is on the fence about this, do it. It's worth the hassle.
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Old 08-17-2014, 11:51 AM
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I modified my trigger by removing a bit of material from the hammer to slightly change the angle so it catches with less engagement. I also weakened the trigger spring by placing the spring onto a drill bit and over compressing it. These changes lowered the pull down to 2-3 lbs. That's good. Unfortunately testing showed that if the trigger was pulled very lightly it had the ability to miss the disconnector and double tap. That's very bad. I fixed this by removed a bit from the bottom front of the disconnector which allows the disconnector to move forward more catching the hammer every time. This also had the unexpected result of making the disconnector move towards the hammer. It is almost touching(0.002) the hammer effectively removing the first stage. Unfortunately I weakened the trigger spring too much and once in while I have to push the trigger forward to reset it but the trigger is a very nice 2 to 2.5 lbs.

I decided to order all new parts and start over because the thought of having modified trigger parts makes me a bit uneasy. The parts arrived and I very lightly polished them. Now the trigger is like others have posted. It breaks at about 4 lbs. It feels like a two stage trigger and you can feel the disconnector touch the hammer and any additional pressure breaks the trigger.

I tried the new trigger spring with the altered hammer and disconnector and it also breaks at 4 lbs but it is single stage with very little creep.

What I learned...

Removing a bit from the bottom front of the disconnector will allow it to move toward the hammer effectively removing the first stage of the trigger pull.

A strong trigger spring is necessary to reset the trigger to overcome the force of the hammer against the disconnector. A lighter hammer spring could be used in combination with a lighter trigger spring but I have not tested this for fear of light strikes.

IMO there is no easy fix to lighten this trigger below 3 lbs until someone designs a new trigger for it.

Last edited by JDouglas; 08-26-2014 at 05:34 PM.
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  #15  
Old 08-26-2014, 04:48 PM
johnnyc14

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Quote:
Originally Posted by JDouglas View Post
I modified my trigger by removing a bit of material from the hammer to slightly change the angle so it catches with less engagement. I also weakened the trigger spring by placing the spring onto a drill bit and over compressing it. These changes lowered the pull down to 2-3 lbs. That's good. Unfortunately testing showed that if the trigger was pulled very lightly it had the ability to miss the disconnector and double tap. That's very bad. I fixed this by removed a bit from the bottom front of the disconnector which allows the disconnector to move forward more catching the hammer every time. This also had the unexpected result of making the disconnector move towards the hammer. It is almost touching(0.002) the hammer effectively removing the first stage. Unfortunately I weakened the trigger spring too much and once in while I have to push the trigger forward to reset it but the trigger is a very nice 2 to 2.5 lbs.

I decided to order all new parts and start over because the thought of having modified trigger parts makes me a bit uneasy. The parts arrived and I very lightly polished them. Now the trigger is like others have posted. It breaks at about 4 lbs. It feels like a two stage trigger and you can feel the disconnector touch the hammer and any additional pressure breaks the trigger.

I tried the new trigger spring with the altered hammer and disconnector and it also breaks at 4 lbs but it is single stage with very little creep.

What I learned...

Removing a bit from the bottom front of the disconnector will allow it to move toward the hammer effectively removing the first stage of the trigger pull.

A strong hammer spring is necessary to reset the trigger to overcome the force of the hammer against the disconnector. A lighter hammer spring could be used in combination with a lighter trigger spring but I have not tested this for fear of light strikes.

IMO there is no easy fix to lighten this trigger below 3 lbs until someone designs a new trigger for it.
Thanks for that info, it is good to caution folks not to remove material from the trigger or hammer hooks or the result will be an unsafe rifle that double taps or goes full auto. When the trigger is pulled the disconnector MUST touch the hammer before the trigger brreaks or it will double fire or go full auto.

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