Mil Spec trigger improvements

Just starting to learn about AR's. I know there a bunch of awesome drop in triggers avaiable, but like to learn what can be done Mil Spec trigger. Just looking so far, I see polishing and lighter hammer spring are needed. How much sear engagement is safe in AR ? Thanks

Blancoalex said:

Just starting to learn about AR's. I know there a bunch of awesome drop in triggers avaiable, but like to learn what can be done Mil Spec trigger. Just looking so far, I see polishing and lighter hammer spring are needed. How much sear engagement is safe in AR ? Thanks

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All of it. Ask Giesselle!

I bought a Geisselle 2 stage trigger for mine. It made a world of difference. From what I have read, the hardened surfaces of the sear and trigger contact points are very thin, and if you polish too much, you will polish through the hardened surface. Not anything I wanted to take a chance with, as I use my rifle as an SRT/Duty rifle.

With AR triggers to improve the stock military type it is kind of like what an old mechanic told me of how to fix and old car once. "Remove the gas cap from the old car and then drive a new car under it and replace." There are plenty of good drop in triggers out there for ARs. One of the least expensive I have found that I really like and have them in 4 ARs is the POF (Patriot ordnance factory) 3.5 pound single stage and they come with anti roll pins and if you shop around and catch them on sale they run $90ish. These triggers are as slick as glass and break like it.

To improve an mil spec. You can find videos on that subject. You can get the smaller polishing stones and polish the sear top face for a crisp clean break. I've taken the hammer spring and bent the legs up about 15 - 20 degrees. This lowers the break pressure. milder bend on the disconnector spring. I saw how light weight hammers were made and I just ground off the back of the hammer head to decrease the weight.

You can get them down to about a clean 5 pound trigger pull that is exceptional. I did ruin a sear by over polishing the top and front. Every time you pulled the trigger it fired twice. So fast between shots it's almost like one bang.

I've bought some expensive adjustable triggers that are really junk. After a few hundred rounds they are out of adjustment even locktighting in the allen set screws. or they even start firing double rounds. I do the three gun competition and the best bang for the buck is this

Thanks for suggestions. May be time for AR Christmas present

Blancoalex said:

Just starting to learn about AR's. I know there a bunch of awesome drop in triggers avaiable, but like to learn what can be done Mil Spec trigger. Just looking so far, I see polishing and lighter hammer spring are needed. How much sear engagement is safe in AR ? Thanks

Click to expand...

Not much can be done with mil-spec Fire Control groups. If there was, the AR trigger market would not be what it is. I've messed with the mill spec triggers ALOT, as i have many of them left from customers having me install after market triggers and not wanting the mil spec one back. So they are sacrificial and I can really dig into it with nothing to lose.
Mil Spec triggers are case hardened. So if you file, grind, polish, you CAN get under the hard metal and into the soft metal. Then the polished area's can rust since you just ground off the coated area. Also if you try to mess with the sear engagement area like you would on a bolt gun you run the risk of doubling, or worse a run away gun. Meaning you can modify the trigger so that it's no longer "one pull, one round discharged" per the BATFE definition of "semi-automatic".
I've seen it with my own eyes.
Throw the mil-spec trigger into your parts box and buy a quality single stage drop in trigger for your AR. You will never look back.

A Larue MBT or Rise Armament RA140, if you really want a trigger

"The 15 minute trigger job"

I have used a ton of different triggers including Timney, Velocity, POF, Rise Armament, CMC and Hiperfire and my favorite is the Hiperfire line. However, I just got a Larue MBT and it seems to be a fantastic budget trigger option as well.

I run Geissle, LaRue, CMC, Rise and Timney.
On an AR10, drop-in's like Rise, CMC and Timney are not the best choice, IMO. The Milspec design is better.
Geissle on my AR10. I have 3 LaRue's,, 1 CMC, 1 Rise and 1 Timney.
I like the Geissle the most, but 3 LaRues cost the same as 1 Geissle and it's hard to tell the difference between them.

P7M13 said:

I run Geissle, LaRue, CMC, Rise and Timney.
On an AR10, drop-in's like Rise, CMC and Timney are not the best choice, IMO. The Milspec design is better.
Geissle on my AR10. I have 3 LaRue's,, 1 CMC, 1 Rise and 1 Timney.
I like the Geissle the most, but 3 LaRues cost the same as 1 Geissle and it's hard to tell the difference between them.

LaRue Tactical MBT-2S Trigger - LaRue Tactical

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I've used the Timney AR-10 trigger on a build and it was perfect. Pricey, but good otherwise.

CMC is what I have. I am sure the others are just as good or better. I could not be happier. Much like a competition rifle but mine is for seeing how many deer and hogs I can kill before they get out of the field. That trigger makes a huge difference in accuracy and speed

Thanks

Buck

I am a RSO at a fairly large private club and also a mechanical engineer. Daves762 posting above is right on. Polishing case hardened parts is asking for a runaway. Unfortunately it almost always come well after the polishing was done and is a complete supprise to the shooter.