Trigger Boosting... Cheap Trigger Job?


Badger Arms
December 24, 2004, 04:22 PM
I've tried this a few times, and it works. I'm wondering if it's a secret or just not important enough to get that much attention. The guns I've tried this in are my 1911 pistol, a few AR-15's and a few AK-47 clones. Here's what I do:

First, unload and clear all weapons.

For the 1911: I put a drop of break-free at the front of the hammer when it's cocked so it goes down into the sear engagement surfaces. Pressing firmly on the rear of the hammer, I pull the trigger. The pressure is not hard enough to keep me from pulling, only makes the trigger much firmer. I do this about ten times and it results in a lighter, smoother pull.

AR-15: I shotgun the rifle and place a piece of cardboard over the rear of the lower receiver. With the hammer resting forward, place a drop of break-free on the sear engagement surface which is a ledge at the bottom of the hammer. I take a pen and wrap a rubber band around both ends. The pen acts as a stop to keep the hammer from striking the bolt hold-open and damaging the receiver. I then use a medium-sized flat-head screwdriver wedged behind the hammer and using the cardboard-backed receiver as a fulcrum, leverage pressure on the rear of the hammer. WARNING!!! Do not use too much force. You can apply a great deal of pressure, but you don't need to. If you can't pull the trigger, it's way too much force. You're looking at stiffening the trigger pull significantly, not breaking anything. Again, pull the trigger 10 times with the extra force, resetting the hammer each time of course.

AK-47: Remove the receiver cover, spring, and any scope you might have that can get in the way. With the hammer resting against the bolt, place a drop of oil on each side of the hammer where the sear engagement surfaces contact the hammer (or one side if it's a single-hook). WARNING!!! When you pull trigger, the hammer will fly forward with significant force to fling the excess oil all over the place. Use eye protection and place a rag or paper-towel over the hammer when you pull the trigger. Apply force between the hammer and disconnector with your flat-head screwdriver again. Remember not to apply too-much force, you can do damage if you do. The goal is to increase the pressure on the sear surface(s) of the hammer and trigger. Pull the trigger 10 times with the additionally pressure, resetting the hammer each time again.

Why does it work? The extra pressure applied to the hammer smashes the mating surfaces together and greatly increases the pressure on any burrs, roughness, or irregularities. When the trigger is pulled, it burnishes or polishes the surface. The oil acts just like honing oil would on a sharpening stone in that it carries freed particles away from the area and allows the surfaces to move with less friction. Imagine rubbing two rough stones together. Eventually, they will mate and create a rather smooth surface on each. You are doing this faster.

What you are doing is essentially accelerating wear on those surfaces and letting them mate together. On most guns, especially new ones, you should see smoother and lighter pulls. They are lighter because there is less friction involved in the total pull weight.

What it doesn’t do: Well, for one it doesn’t hurt anything if you do it right. It doesn't change the geometry or spring pressure; it just breaks the parts in. Garage-gunsmiths often use dremmel tools, sharpening stones, sandpaper, files, hammers, chisels, hatchets, butcher knives, and vice grips to accomplish ‘trigger jobs’ at home. You don’t need to do this… leave it to a professional. If you want it smoother, try my method and save yourself a trip to the gunsmith when you break something.

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December 24, 2004, 04:41 PM
Or "High-pressure lapping"?

You're not really grinding or stoning, so I guess there's no danger of going through any surface heat treatment on the sear mating parts.

I may have to try it on my SAR-1. I may use Flitz or Pol on mine, though.

Badger Arms
December 24, 2004, 05:26 PM
I prefer not to use any polishing, lapping, or grinding compound for this because it works wonderfully without it. I don't want to harm the breaking surface any nor do I want to take off any metal. What I'm looking for here is surface finish, not any metal removal. If 10 times without anything does the job, why mess with it?

Fireblade Systems
December 25, 2004, 01:26 AM
Applying to much pressure or doing this over and over can damage the parts.

Andrew Wyatt
December 25, 2004, 03:10 AM
I've heard it called "the GI trigger job",usually with scorn.

December 25, 2004, 03:21 AM
I think judiciously applied this can help - almost any gun. It is more of a ''seating/bedding in effect ... as badger says - a carefully accelerated useage process.

The warning comes however in knowing what is ''judicious'' ... excessive force WILL be deleterious potentially. I doubt there is any harm in a ''low-key'' attempt at this ... but the warning still applies.

December 25, 2004, 03:38 AM
Sounds interesting. For your AR15, what improvement have you noticed? Was it readily noticeable, and in what percentage (estimated)?

Badger Arms
December 25, 2004, 04:00 AM
As for the level of improvement, it amounts to a quality increase for the most part. There is no roughness... you can't feel the metal rubing against metal. Although it FEELS smoother and lighter, you'd have to be the judge. Best improvement I've seen was with my MAK-90 triggers and my Olympic Arms parts. The OlyArms parts were phosphate so it was quite noticeable when the roughness wore off. As for the MAK-90 parts, I used the Tapco G2 fire control group. The pull felt like glass after I was done.

December 25, 2004, 04:28 AM
As for myslef, Ill stick to a real trigger job when necessary...:)

The 1911 technique is probably good for Rock Rivers and Kimbers, a Colt doesnt need it :what:

As to AKs, theres somehting called Ron Power


December 25, 2004, 05:37 PM
A year or so ago, or maybe it was last summer, the Tuner was working with my Springer to remove some grittiness in the trigger. A little polishing and boosting did away with the gritty feel entirely. My trigger pull remains at 5.4# but it feels lighter and breaks pretty close to perfect.

I'm happy with the outcome.


December 25, 2004, 08:47 PM
Hey Wild

We don't think Alaskans are crazy, just a bit squirrely. You know, kind of "beyond west coast".

Badger Arms
December 25, 2004, 11:23 PM
Hehehe, you say that from the U.P.? Go figure. You'd HAVE to be crazy to live there!

December 26, 2004, 01:06 AM
My Kimber 10MM came with a horrible trigger - figures for a gun with "Target" in the name of it. :)

I read about boosting and tried it - 10 times with firm pressure and it really helped take the creep out. Between that and just shooting it it's much better now.

Brian D.
December 26, 2004, 10:20 AM
Another user of this technique chimes in! You just have to do the boosting judiciously and not get carried away. Did this with one of my 'Rincos, the one that's still going strong about 20K rounds later. Trigger pull hasn't decreased enough to measure since the boosting/slight polishing got it to 5lbs.

Jim Watson
December 26, 2004, 10:54 AM
My FLG boosts the hammer some as the final step of a conventional trigger job. He doesn't apply as much pressure now as he used to, after rolling the hooks right off an early Kimber MIM hammer.

December 26, 2004, 02:38 PM
Just like Jim said.... I wouldn't want to do it to MIM parts....only real steel.

December 26, 2004, 04:47 PM
I rolled the hooks off a Wilson A2 hammer "boosting". I guess I didn't know my own strength?
Its not just the MIM :)

December 26, 2004, 06:12 PM
Have to concur with Jim and Anthony. Boosting does knock the rough edges off and smooth things up...but it has to be done gently...or be prepared to fork over the cost of a new hammer.

January 7, 2005, 10:50 AM
I like the idea.Everyone knows that just plain shooting a gun will smooth it's action. But why wait a couple thousand rounds? There are way too many examples of guns and other machinery where some type of lapping process is used to get a real good fit between parts to ignore the process.And, just like everything else, it can be dangerous if used improperly.

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