"Houston...We may have a problem "Sear Tilt"

[Evopsych]

First of all...Let me say that I dearly hope I'm wrong about this. But after reading Setzer's torture test results the other day and comparing them to a similar problem with single action fire, that I recently had. I've taken a good hard look at the two piece sear on the FN FNP's...And I'm afraid there may be a design problem.

The Browning Pro's use a one piece sear. With a bar that fits into a slot on the sear actuator (Part #40 on the Browning Pro) lifting the sear and allowing the hammer to fall. The Browning sear has two holes on the bottom that the sear pin (Part #41 on the Browning Pro) fits though and tilts up on to release the hammer. This should work great, as the sear is evenly lifted in one piece and rises evenly allowing the hammer to break cleanly. One spring holds tension on the sear (Part #42 on the browning Pro.)

http://www.freespaces.com/laliqueinf...ro940parts.pdf

The FN's on the other hand use a two piece sear arrangement



(Please forgive my camera)

The Sear Actuator has been elongated, with a notch, that a tab on the single action sear fits into. Lifting the single action sear to release the hammer in single action. Here lies the problem. It appears that the tolerance of the hole in the single action sear, that the single action sear rides the sear pin on the upswing of the release, is to wide and allows the single action sear to tilt as the sear actuator notch pushes the tab on the single action sear upward for the release.







I've posted three pics, of three different trigger pulls in single action. All of the picks were taken as the trigger was being pulled in single action and hopefully the pics are clear enough to show the tilt of the single action sear, just before hammer break. The Tilting of the sear can be visualized with the slide on as well.

The tilting single action sear causes the corner of the single action sear to retain the hammer and is the cause of the single action "pull all the way to and though the trigger stop" malfunction. It can cause a malfunction in the FNP9M (And possibly the other FNP's as well.), where one pulls the trigger all the way to the trigger stop and the pistol does not fire, unless about 20 pounds of pressure are exerted on the trigger.

I hate to be the one to bring this bit of bad news and encourage all FNP owners to examine their pistols, disassemble and look to see if this problem is as common as I suspect it is. Again I dearly hope I'm wrong about this. I've been looking at the problem for two weeks now and didn't want to post this, until I was absolutely certain that the problem was not an isolated incident, limited to my personal FNP9M.

This is in no way FN bashing, because I love FNH USA. I see it more as we the owners of FN products, acting as FN's pit crew and finding a small glitch, that is probably easily remedied to make the FNP a better pistol.

This problem could probably be solved with a .02 cent bushing for the single action sear or making the tit on the sear actuator that the trigger bar hits slightly longer.

There is no need to start an internet brushfire of criticism of the whole FNP design here. But this is a potentially serious FTF problem that we would be remiss in not bringing to FNH USA's attention.

Evo

[Setzer77]

How are you getting yours to do that? Simply pulling the trigger won't make mine do it, no matter how slow. Is there a certain series of events, or certain situations that would cause this to happen?

[oldtexan]

You say that this problem can't happen with the Browning Pro pistols. Can it happen with the SAO versions of the FNP or only the DA/SA versions of the FNP?

Thanks.

[Evopsych]

I don't own a browning Pro...So I can't state with any certainty, but looking at the design of the one piece sear. I'd make a guess that it would certialy be harder for this to occur.

As far as I know...Nobody but the guys at FNH USA have seen the inside of an FNP SAO Fire Control Group yet. Though I'd be very surprised if the coming SAO FNP had a two piece sear group.

On a side note the FNP has two (Browning Pro Part #42) springs. one for the sear actuator and one for the sear itself.

[galland1]

I cannot make mine do this. It comes up evenly no tilt no matter how I pull it.

[Evopsych]

I admit we're in dangerous and uncharted waters here.

I've pulled the fire control group again and have pulled the sear pin, sear actuator and sear and am considering the problem further (Yes I know taking apart the fire control group probably voids my warranty, but its dead simple and I didn't just start taking apart guns yesterday.)

Just examining the sear on the sear pin. I observe a little slop in the tolerance of the hole in the Sear and the Sear Pin, that seems to account for the sears ability to tilt.

It almost appears that if I could find a paper thin washer that would go over the sear pin between the sear and the poly wall of the fire control group this problem might be solved.

I need to run down to Lowes and scratch my head a bit.

Evopsych...Taking one for the team.

[Setzer77]

I still don't understand how you're actually getting yours to do this. Does this occur after a string of firing and it gets dirty, or what?

[Evopsych]

Well Setzer...how do you suppose yours did it...Gunk in the action really isn't much of a technical explanation.

Something must have been going on in there to make your hammer not fall. 20 pounds against the trigger stop ain't the normal state of affairs...Something made that happen. Something caused your sear not to rise fully and release the hammer.

I'm endeavoring to figure out what that something is. If there's a single action reliability problem. I'd like to know about it and fix it now, on this board, rather than wait until somebody has to do a single action critical shot placement, in a life or death situation and have the trigger go all the way to the stop and the hammer not fall.

[galland1]

Seems like I read a review someplace where the reviewer received his review piece doing this. Madogre maybe.

[Evopsych]

Do you remember where the review was?