Airsporter trigger tuning

ChrisHobbs

ChrisHobbs

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I got my old Mk4 airsporter out at the weekend for a spot of card cutting, and having not shot her since I got my huntsman, back in may, I’ve realised just how horrible the trigger is. It’s so heavy I actually checked it was cocked on the first shot!
So my question is
Is there anyone you guys could recommend that works on them?
She’s really served me well over the 35 years I’ve had her and I think she deserves some well earned love.
At some point she could also do with re blueing and a stock refurb.
But without losing all her character (her dents and dings hold a lot of fond memories).
I’m pretty sure who I’ll be talking to about the stock, but not sure about the rest. Or what the best order is to get things done?
 
Quite often I find the trigger adjuster screws wound right in on bsa's this makes the trigger heavy like that, try winding the allen screw out a turn or two. It's NOT a metric one btw.
 
If I recall, yours is a Mk 4 - if so, there should be 2 grub screws in front of the trigger. The one nearest the trigger is listed by Chambers as the "trigger adjusting screw", the one furthest away from the trigger (nearest the muzzle) is the trigger stop screw. I am guessing it is the trigger adjusting screw that would be adusted to increase/decrease weight.
 

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Ascham said:
If I recall, yours is a Mk 4 - if so, there should be 2 grub screws in front of the trigger. The one nearest the trigger is listed by Chambers as the "trigger adjusting screw", the one furthest away from the trigger (nearest the muzzle) is the trigger stop screw. I am guessing it is the trigger adjusting screw that would be adusted to increase/decrease weight.
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Thanks mate!
I’ll have a look when I get a chance.
 
Hope this helps, the big grubscrew (the one that can be seen) appears to adjust only the total length of travel of the trigger after the sear has been tripped. It has no bearing on how much the trigger engages with the sear, or the point at which the sear is tripped, or how much weight is required to trip the sear.
The second grubscrew (which cannot be seen in the photo) appears to bear upon a spring (which also cannot be seen in the photo) which pushes against the trigger - thus winding this screw out should reduce initial trigger weight.
 

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Looking at an exploded parts diagram, it looks like the rear of the sear is pushed against a spring above the sear pivot point. When the trigger is pulled it is this spring which causes the sear to rotate thus freeing the piston latch rod from thd sear.
It looks like there is no means of adjusting the force exerted by the sear spring.
It also looks like force required for the trigger to break free from the notch it is held in place on the sear is determined by the geometry of the trigger and sear and the geometry of how they both pivot - thus there is no means of adjusting the weight of the second stage.
 
Ok mate thanks. I’ve found the right sized Alan key now, so it’s just going to be a case of trial and error.
The plus side is it can’t get any heavier! 🤣
 
crowbar said:
Just to note the allen key size is 1/16" and Bondhus do a good set , it's the one with the yellow handle.
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Luckily got a decent set of both metric and imperial allen keys. One of the benefits of having to work with antiquated woodworking machines for so many years!! 🤣
 
I have an a superstar with a heavy trigger appox 3.5 pounds pull was wondering if you managed to adjust yours
 
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