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Discussion Starter · #1 ·
I Recently bought a new XCR (New firing pin and gas adjustment type) and I followed the recommended break in procedures, I fired close to 320 rnds on gas setting 4 and then moved it to setting 3 for 60 rnds and then down to 2 for 60 more rnds, I loved it, the gun fired every time that the trigger was pulled and the break in was as easy as possible. I was using PMC Bronze 55 gr FMJBT and the gun was bench rested much of the time. Ill add a full range report soon.

I only have two questions,…. For now

First – The trigger had a bad bite and by the end of the session it was beginning to sting, it felt almost as if it was slapping my finger after every pull, it slacked off a bit as I fired more rounds and slacked even more when the gas setting was turned down, my girl friend who was helping me during the break in also had the same experience with the trigger. I’m used to the rough trigger on my STG58 Austrian FAL and the even rougher one on my CETME, but the trigger on the XCR was much more uncomfortable. Is this normal, and if so how long will it take for it to break in, and is there anything I can do short of sending it in for a trigger job? I’d really love to tame the trigger bite, let me know if anyone has any ideas.

Second - My buffer lost a corner, and looked quite beaten up, the broken piece fell off when I was cleaning. Is it normal to see that much wear and tear after 400 rnds or do I need to just get a new one?

Thanks for the help, I love this rifle, I loved the time breaking it in, and im looking forward to shooting it more.
 

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1 - Most trigger systems come with slight burrs on them, mostly on the hammer sear surfaces. We try to catch them with files before they leave the shop, but some escape us. Most of the time, the first 2-300 rounds will take care of the burrs with wear on the parts. Basically, the hook of the disconnect takes longer to release the hammer because of the burrs, which is causing the issue you are experiencing. Take a small file and very gently touch up the hammer sear surfaces. This will smooth the glide right out, if it's still not to your liking. Just make sure not to file too much.

2 - Turn your gas down. Your buffer shearing into pieces is an indication that your rifle is getting too much gas, thusly overcycling. Turn it down a setting or two. Your rifle is fully worn in now, and doesn't need as much gas now.
 

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While you are sitting around watching TV dry fire a few hundred times, wont hurt anything and should help with the trigger. As for the Buffer, Terra said it all.
 

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Something I did while doing all the dry fire was add some polishing compounds to the contact points. I used the heaviest I could find for automotive paint finishes. I didn't figure anything designed for paint could remove enough metal that quick to change geometry but it seemed to really smooth out the trigger. It is still a little heavier, but has a distinct 2nd stage and crisp. It will make a mess of the lower receiver and I had to completely strip it to get out all of the compund.
 

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Discussion Starter · #6 ·
Does anyone have a couple of pictures of a properly smoothed hammer sear? I’ve got my jewelers files and Emory cloth ready, but I’d like to see a finished one before I try my hand at the task.
 

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Well I'll still take em if you need me to.All I really did was polish the finish off of the sear/hammer contact points with Flitz metal polish and a cloth buffing wheel on a Dremal.After your done they look like a mirror.I think Bill Springfield also changes the geometry.I didn't feel this was necessary after polishing and trying it out,but if your looking for really light trigger then he might be your man.Personally on a 'fightin iron',I think it's dangerous to go to light,but to each his own.



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Here is a pic I hope helps.Fair warning,I can't take a closeup to save my ass but hopefully you get the idea.Do NOT change any angles unless you know exactly what your doing.Files can remove alot of material quickly,and a little goes a long way on trigger parts,I advise against using one.Again I used a Dremal with a cloth buffing wheel and Flitz or similar metal polish.
Polishing in increments is advised,It seems every time I did a little more polishing it broke lighter,maybe it was just smoother and crisper,but It's about how it feels,not the pull weight anyway.
I once again feel I should warn anyone attempting this,going too light,taking too much material,or changing any angles,can cause a dangerous situation if you don't know exactly what your doing.Don't get me wrong polishing any metal surface ain't brain surgery,but you should take your time and be carefull too.When your done a little application of Teflon grease seems to make it feel even better and seems to last for a good while.Again I hope this helps.



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Keep in mind that performing a trigger job involving polishing/filing sear surfaces can compromise the rifle's functionality once a 7.62 is installed. The slick surfaces + heavier hammer spring do not work so well together. If you do experience issues, you will end up having to buy a new hammer. :buckteeth:
 

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Terra,I'm not sure exactly how having a heavier spring could effect how the trigger functions after polishing the hammer/sear surfaces.It will make the first stage of the trigger pull heavier,just as installing a lighter hammer spring will reduce first stage pull weight,but will not reliably ignite hard primer(Wolf,Silver Bear)ammunition .
If you needed the heavier hammer however,you would probably need to polish the surface on it to match the corresponding wedge on the front of the trigger.If you didn't,it just wouldn't feel as smooth as it would if both surfaces had been polished.Filing on the other hand changes angles and can effect the way the geometry of how the parts fit together.That's why I don't recommend anyone doing that unless they experience doing so,or you could be creating a possibly dangerous situation,or at the least could need some new parts if you butchered the parts.
I'm curiouse now,send me a 7.62 hammer spring and I'll be the Guinea pig. ;)



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Okay, I already covered this issue with a customer who had the problem.


When the sear surfaces are polished too much, the greater tension in the new hammer spring causes the hammer to spring forward. The customer had a job done by Bill, in which the sear surfaces were polished smooth. His old hammer spring worked fine with it, but once the much stronger hammer spring was installed, his trigger would not stay set back. When shooting, he was getting double and triple fires because of the new spring with the polished hammer.

I'm not an engineer, but this is something you guys need to be careful with.
 

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Bill changes the geometary of the AR trigegrs and I believe he does the same on the XCR to get a better fit. Let him know the isuse you have and see what he comes back with. He is a good guy and will sort you out.
 

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Discussion Starter · #17 ·
Sry, I havent been on in a while, duty calls.... i took the lower off and sat on the couch and read the forums while I cocked the hammer and fired it a couple hundred times into an old dish rag. I could feel the difference after a while and now i need to get back out to the range to shoot again. I held off on polishing anything yet untill i feel how it does at the range. I am a little hesitant to do any work on it yet because without a round actually being fired i dont have a real good handle on how its gonna perform after the dry firin into the towel. Ill try to get to the range and put a few mags through it this weekend, ill give a better update of my progress then.

Quick question, i havent fired it without the dish towel in front of the hammer, (except those few times that i didnt get it close enough.... ooops) but i saw how it rested on the receiver after it was fired, and i wondered if there is any worry of receiver deformation or cracking from allowing it to strike metal on metal?
 

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I am not sure if it is a problem or not but mine has some slight deformation from where the hammer has hit the reciever from normal firing I have not done any dry firing with it though
 

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the hammer banging into the lower won't hurt a thing. Just catch the hammer with your hand, sillies, and you'll save the lower the beating.
 

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