fas 6004 trigger adjustment

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bassplayer
Posts: 11
Joined: Wed Mar 25, 2015 4:58 am

fas 6004 trigger adjustment

Post by bassplayer »

Does anybody know how to adjust the fas 6004 trigger? - because it is a mystery to me! The diagram provided with the pistol and the instructions use words like "drop point" which are unknown to me.
David Levene
Posts: 5618
Joined: Mon Mar 01, 2004 12:49 pm
Location: Ruislip, UK

Re: fas 6004 trigger adjustment

Post by David Levene »

I would suggest backing off screw number 4 (anti-clockwise).

Adjust screw number 3 until the trigger breaks in the best position for you

Turn screw 4 clockwise, a tiny bit at a time, until you can feel the trigger stop just before it breaks. This is the screw that sets the difference between 1st and 2nd stage.

Screw 1 adjusts the weight of the trigger.

Screw 2 adjusts the amount of travel before the trigger breaks.

It's pretty much the same as the 604.
slofyr
Posts: 273
Joined: Sun Oct 10, 2004 1:12 pm
Location: Pacific NW

Re: fas 6004 trigger adjustment

Post by slofyr »

[Combined thread redundancy deleted.]

http://www.targettalk.org/viewtopic.php ... 71#p257920
Last edited by slofyr on Mon Nov 07, 2016 12:30 pm, edited 1 time in total.
bassplayer
Posts: 11
Joined: Wed Mar 25, 2015 4:58 am

Re: fas 6004 trigger adjustment

Post by bassplayer »

The response is much appreciated! Thanks for taking the time to reply with good, clear instruction and description of the working of the trigger. I shall now be able to set my trigger armed with a working knowledge of what I am doing.
bestel74
Posts: 1
Joined: Sat Nov 05, 2016 4:25 am

Re: fas 6004 trigger adjustment

Post by bestel74 »

I just received my FAS 6004, and I just want to be sure of what I need to do :

1) I want to lower the release pressure weight (520gr)
+ anticlockwise screw n°1?
But does this screw affect the "entire" weight ? I mean 1st stage too ? Or just the 2nd stage release pressure?

When i anti-clockwise, i can't get it under 520gr, even backing out completely.


Thanks :)
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Kicker
Posts: 7
Joined: Sun Oct 30, 2016 10:46 am

Re: fas 6004 trigger adjustment

Post by Kicker »

As I told you on the French forum, the screw 1 controls the trigger weight for the whole pull. That includes 1st and 2nd stage.
If unscrewing it to the maximum is not enough to get the weight you want, then tighten the screws 3 and 4 so that there's less tension on the trigger when the shot goes off.
But doing so will shorten the trigger pull, so then you should also also loosen the screw 2 to lengthen it accordingly.
slofyr
Posts: 273
Joined: Sun Oct 10, 2004 1:12 pm
Location: Pacific NW

Re: fas 6004 trigger adjustment

Post by slofyr »

bestel74 wrote: 1) I want to lower the release pressure weight (520gr)
+ anticlockwise screw n°1?
But does this screw affect the "entire" weight ? I mean 1st stage too ? Or just the 2nd stage release pressure?

When i anti-clockwise, i can't get it under 520gr, even backing out completely.
Studying this drawing should help you understand what the adjustment screws do. The drawing illustrates how the FAS is set up from the factory with a two-stage pull. As the trigger moves rearward, the 1st-stage upper screw in the trigger blade is the first to contact the sear lever followed by the lower 2nd-stage screw. Because of their distances from the fulcrum/pivot of the trigger, the leverage each screw has against the sear lever is different: the top has more leverage, the lower has less. Adjusting these two screws can make the trigger 1) a 2-stage pull with various lengths of travel and resistance for each stage, 2) a light-rolling single stage if you back the lower screw out of engagement or 3) a crisper and heavier single-stage pull if you back the upper screw out of engagement.

The screw just forward of the trigger pivot, in conjunction with the first screw to contact the sear lever, will reduce or increase sear overlap to reduce or increase trigger travel before the pistol fires. This screw will also reduce or increase trigger reach.

The screw at the forward part of the trigger guard regulates trigger pull. Backing it out will reduce the preload on the spring and lighten the pull.

Image
Last edited by slofyr on Mon Jul 10, 2017 9:26 pm, edited 3 times in total.
TenMetrePeter
Posts: 603
Joined: Sun Sep 04, 2016 10:59 am

Re: fas 6004 trigger adjustment

Post by TenMetrePeter »

Slofyr's description is the one to follow.
The 6004 and later 604 are difficult to get near 500g without modifying the spring and polishing sears, however if you can get 520g then it's as near to the ISSF limit as I would like to go. You might want to Loctite the screw in the last few threads.
The 604 and 6004 have one of the easiest triggers to adjust and the easiest pistol to strip If only they all had the backstop fitted which disappeared around the milennium.
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Kicker
Posts: 7
Joined: Sun Oct 30, 2016 10:46 am

Re: fas 6004 trigger adjustment

Post by Kicker »

He asked the same question on another forum. Apparently, he has managed to reduced the trigger weight by following the advice I provided.

His problem was that even by backing out the screw at the front to the maximum, he couldn't lower the trigger pull to 520g.
That's why I suggested to tighten the screws located on the trigger, controlling the stages.

By doing so, the spring controlled by the front screw has less tension when the 1st and 2nd stages are started, effectively reducing the trigger weight when the pivot behind the trigger has rotated enough to trigger the shot.

To be honest, I'm not a big fan of this system. If you have a specific course that you want in mind, and you want to adjust your trigger accordingly, it can be very tedious.
Plus, you can't adjust the weight of each stage. For that, you'd need to be able to put the screws closer of farther from the pivot, or adjust the resistance of the spring that's attached to it...
d-cuttler
Posts: 29
Joined: Sun Apr 06, 2014 1:47 pm

Re: fas 6004 trigger adjustment

Post by d-cuttler »

I know this is an old thread, but the subject is still relevant.
Having just purchased a new FAS 6004, I too have been trying to understand how the trigger adjustment works.

One of the problems is there are 2 springs that regulate the trigger weight. One is under the weight adjustment screw, and another under the arm that screws 3 & 4 contact. Even if you back out screw 1 completely the other spring will set the minimum trigger weight.

What I did was to replace the 3m x 6 trigger adjustment screw with a 3m x10 socket head machine screw from Ace Hardware for about 60 cents. And have it almost completely screwed out. In effect about all it is doing is keeping the spring from flopping around. Then by fiddling with screws 2,3,and 4, I now have a single stage trigger that is very crisp, and breaks at about 10 oz. I can live with that.

This situation is very much like the trigger in my Crosman challenger which shares its trigger with the Maruder. If you back the trigger weight screw all the way out, it is still limited by a second non adjustable spring. The fix is to remove the 2nd spring, making the trigger weight spring the only one that sets the trigger weight. Something like this could be the answer to making the FAS 6004 trigger make sense.

I may order a few of the springs, an play around with bending them to a lower tension.

As the manufacturer did not see it of importance to have an adjustment hole in the trigger guard, having a ball end metric allen wrench makes inserting and adjusting the new trigger weight screw much easier.

I hope this helps any others who may be fighting with this problem.

David
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