Modifying Sear & Rod

[EclipseClassic]

These guidelines seem to be widely accepted on these boards:

For Dummies
There are people out there who think they can achieve better performance by modifying parts. They are wrong. If the existing marker could reach a better performance as it is, it would come that way out of the factory.

7. DO NOT shave the sear or adjust the trigger rod.
8. DO NOT modify the on/off pin length, you will end up with a marker that either wont work, or wont be allowed anywhere. This also voids your warranty.

I disagree. Obviously we are tinkerers and we have modified the performace of our mags for years. Just because AGD doesn't or didn't do it, does not mean it can't be safe or functional. I would like to think that most of you guys would agree with me there.

I cut my sears on my LV7 mags. It makes the trigger pull lighter, shorter, and crisper, causing decrease short stroking, higher ROF, & increased performance. If one cuts and polishes the sear tastefully the benefits far out weigh the deteriments.

I have said all of this to say:

Cutting/drilling/polishing your sear can be a very informative and good thing. So experiment, you might find out something you didn't know about your old mag.

LV7 bolts aren't too hard to come by these days, I say hack that sear in the name of science! Figure out what works best for you.

It took me 10 years and at least 20,000 shots before I had to replace my bolt. Best $12 bucks I ever sacrificed for +7-10 bps from my stocker.

[questionful]

What would cutting the sear accomplish?

[michbich]

We want pics of that cut sear. :shooting:

[maniacmechanic]

What would cutting the sear accomplish?

The sear doesn't hold the bolt as long if it is shorter , I asume he is talking about shaving the top down , if you shave too much , it won't catch & hold the bolt , results :shooting: rapid fire

[ThePixelGuru]

So what exactly did you do to your sear?

I can get a BPS increase out of a Tippmann by removing the sear - that doesn't mean it's a good idea.

[EclipseClassic]

If you polish the top of the sear on the end where the bolt is released you will get a slightly smoother pull. Hardly noticable though.

However, if you cut the edge of the sear and then polish it, the trigger becomes shorter & smoother. This does effect the relationship between the bolt and the sear. The harder the edge angle, the more damage the sear will do to the bolt over time. We aren't talking about nylon here though, this is quality AGD stainless we are working with. It takes a long, long time to chew up a bolt if you only slightly angle the sear.

If you are over zealous with the cut your sear can become useless and the gun will double fire or go full auto. The key is finding a good relationship. A sear that is slightly cut and polished will still catch the bolt without chewing it up. There is a very happy median between full auto & short & soft. It is best to do a little grinding at a time until you are happy with the result. It is a give and take process. The harder the angle the softer the pull, the harder the angle the quicker the bolt wears down. I started by doing a little bit at a time until I rendered my sear completely useless. Now I know when I've cut too much and when I still have room to go. It is food for thought, I would experiment with it. I don't see it brought up much on the board any more. Back in the day I would do anything to get my mag shooting faster than cockers.

I know members often move the rod up which creates a much shorter pull, but also stiffens the pull considerably. By combining a raised rod and a cut and polished sear, you can have on really fast shooting classic. Here are some simple diagrams, very very simple...

http://img519.imageshack.us/img519/209/68143451ry3.jpg

http://img209.imageshack.us/img209/8387/33645867rp5.jpg

http://img234.imageshack.us/img234/7550/project1dp0.jpg

[questionful]

You could just unscrew the trigger rod out some. You'd have to compensate with the on/off, but I'd rather have to buy a new on/off pin than a new sear.

I've moved the trigger rod closer to the sear's fulcrum on a classic sear. This combined with a ULT is what I've always wanted to put on a classic. But I just have my RT now. I will be messing with the trigger rod soon. :D :shooting:

EDIT, as of your new pic:

Oooooooooooh!! Cut it like that. I've never thought of that! I'd rather not though. Does it really have a noticeable effect? I never thought friction between the bolt and sear had an effect on trigger pull.

[EclipseClassic]

warning!

Please Don't Do This To A Lvl10!

Lvl7 Who Gives A Damn???

[EclipseClassic]

You could just unscrew the trigger rod out some. You'd have to compensate with the on/off, but I'd rather have to buy a new on/off pin than a new sear.

I've moved the trigger rod closer to the sear's fulcrum on a classic sear. This combined with a ULT is what I've always wanted to put on a classic. But I just have my RT now. I will be messing with the trigger rod soon. :D :shooting:

Unscrewing the tigger rod can help with preference, but it doesn't soften or shorten the trigger pull. There is no need to adjust an on/off to compensate for a trigger rod adjustment.

A ULT and a sear job are two different things. Im not comparing the two. Just so ya know.

[questionful]

Unscrewing the tigger rod can help with preference, but it doesn't soften or shorten the trigger pull. There is no need to adjust an on/off to compensate for a trigger rod adjustment.

A ULT and a sear job are two different things. Im not comparing the two. Just so ya know.
Unscrewing the trigger rod CAN shorten the trigger pull. You just have to be very careful about the timing. You have to make sure your on/off closes before the sear lets go of the bolt.

And a ULT isn't a sear job of course, but moving the trigger rod up the sear arm makes the trigger pull too hard. But combine it with a ULT and it should be great. I've never tried it before though.

[athomas]

The only thing that can shorten the trigger pull, is by altering the timing. That means you need to shorten the on-off pin which allows the sear to catch less of the bolt before it opens the on-off.

The relationship between the on-off closing and the sear releasing the bolt always remains the same until you alter either the sear or the on-off pin. Adjusting the trigger rod by itself only changes where the trigger sits in relation to the sear. Too long and the sear can't rotate forward enough to open the on-off. Too short and the trigger can't push the sear back far enough to release the bolt.

Filing the top of the sear does not affect the trigger pull. The trigger pull is affected by the pressure of the on-off pin and the bolt force on the sear tip. The top of the bolt is only in contact with the bolt if there is bolt stick or something else that interferes with the bolt resetting. The top edge then hits the bolt lip and prevents the sear from resetting. This keeps the sear back to prevent the on-off pin from opening.

You can make a slight adjustment to the sear for better pull, but even that doesn't do much, especially on the level 10 bolts where there is almost no force exerted anyway. The holding edge of the sear is tapered. That tapered lip should be parallel to the tangent line at the point of contact. On most sears, if you pull the trigger, the bolt gets pushed back a bit as the sear rotates. If you adjust the sear tip so that there is no movement, then you are not pushing against the internal pressure in the chamber and the pull force should be reduced.

Altering the length of the on-off pin shortens the trigger pull by shortening the distance required to close the on-off before the sear is released. The side effect of this is when the on-off pushes the sear forward it does not hold as much of the bolt lip. In some cases as the bolt gets pushed forward by recharging air, if the sear isn't catching the bolt with enough contact area, the sear tip becomes damaged.

[EclipseClassic]

Once again, I am not talking about LVL10 bolts. Please do not do this to a LVL10.

Adding a RT on/off, aftermarket on/off, or ULT can drastically change your outcome. I have seen A.I.R. valves shooting 12+ bps mechanically with a modified sear, on/off upg, and some tuning.

If you have not tried cutting the sear for your self, don't knock it till you've tried it. I have, many times, and each time with better and better results. It does soften and shorten the trigger pull. The sear in most cases does not wear, the bolt will wear over time. We all know how hard that sear steel is and in most cases the bolt alone will need replaced.

The point of this thread is not to start an arguement. It was only created to inform.

Worst comes to worse your out a sear and a bolt, and have learned something new.

But in most cases, with a little experimenting you can easily pick up 5+ bps, less short stoking, and a new appreciation for an A.I.R. mag. :)

[questionful]

While we're on the subject, how will timing my sear affect the wear? My sear has a carbide thing welded to the top, I guess all classic RT sears are like this, I'm not sure if others are, but I assume the sear won't be the problem no matter what I do to it. Am I wrong? And what about the bolt? Will having less contact on the sear affect the bolt? How much?