External adjustability for the Benji trigger: Quick, simple, and zero cost.

External adjustability for the Benji trigger: Quick, simple, and zero cost.

Joined: May 12th, 2001, 1:29 pm

December 13th, 2015, 12:56 am #1

Here's a quick and dirty mod' that implements an external adjustment for Benji trigger sears that, in all humility, I really don't think could be much simpler, cheaper, or easier.



Just in case it's not obvious how it works, it's kind of a don't raise the bridge, lower the river thing.

The scrap of innertube pushes the trigger housing away from the bodytube (and therefore away from the hammer), taking the sear along with it. This increased spacing reduces engagement between hammer and sear, which is then partially adjusted back out with the housing screws (screws on both sides adjusted symmetrically to maintain balance) until trigger creep suits the tastes of the shooter.

It works with both the stock sear and SuperSear, but since the stock sear is not a true 2-stage design, it's impossible to adjust away all the 2-stage creep without compromising safety. With the Super, by contrast, since it is a true 2-stage, you can.

Although the housing screws typically end up slightly offset from their countersunk holes in the body tube, as shown in the photo this is really neither visible nor (IMHO) cosmetically objectionable.



This may be of particular interest to users of my Benji' SuperSear, which is available both as part of the DIY ACP392 conversion kit (currently for sale in the Yellow Classifieds), and for sale as a separate part from a well known retailer.
Last edited by Afrikane on February 11th, 2018, 8:17 pm, edited 1 time in total.
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Joined: November 17th, 2006, 3:51 am

December 13th, 2015, 2:44 am #2

HAve an old Challenger 2000 co2 that uses the same trigger system...will give the idea a try.
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Joined: May 12th, 2001, 1:29 pm

December 13th, 2015, 3:13 am #3

If you're using the stock sear with its only simulated "2-stage" trigger, you'll need a pretty thick spacer and, as mentioned in the OP and as I'm sure you already know, adjusting for zero creep means adjusting for zero engagement. Yikes!
Last edited by pneuguy on December 13th, 2015, 3:35 am, edited 1 time in total.
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Joined: November 17th, 2006, 3:51 am

December 13th, 2015, 2:58 pm #4

Works as advertised!

Test rifle:



Trigger unit: (that light striker, weak spring, and a tiny gas port on the valve is makes this one a 4.5-5 foot pound rifle, but with 80-90 shots per 12gr.)



Used harder plastic shims in various thicknesses (mostly from 12gr shells/ wads). Not really compressible, but I didn’t have anything “squishy” in the right thickness.

No real trigger gauge, so I “cheated”.

TRIGGER PULL GAUGE CHEAT:
With rifle captured loosely between thumb and fore finger, pointed down, on top of a digital kitchen scale, the weight of the rifle is 6 pounds 10 oz. CAREFULLY and SLOWLY pulling up on the trigger and watching the scale read out, can get the weight where the sear tripped. Difference between the two would be the trigger pull.

Had worked this trigger over for smoothless and a crisp pull, so it’s starting off way-better than a stock 387/392. Never did anything about the take-up as it never really bothered me; it’s not 1st stage as there is nearly no real weight to it, but what weight it adds to the trigger pull is minor (scale claimes it is something like 1 ½ to 2 oz).

As tuned: 1 pound 8oz.

.032” shim = 1 pound 2 oz.

.054” shim = 14oz. BUT, the trigger malfunctioned about 2 out of 5 tries.

Evidently the .054" shim as a little too much. If I used a compressible shim, could just change the shim thickness by how tight the unit was attached, but as I was using firm shims, decided to back track to the .032” shim and a 1 pound 2 oz. pull. Boucned the rifle around on its butt and it didn’t fire. Will see what it turns out to be in pull (and safety) once the sear has mated up to its new angle.

May go to a "split the difference" shim thickness later.

Thanks.
Last edited by gubb33ps on December 13th, 2015, 3:04 pm, edited 1 time in total.
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Joined: May 12th, 2001, 1:29 pm

December 13th, 2015, 4:31 pm #5

...because it allows, not just reducing 2nd stage weight, but controllably dialing away absolutely all perceptible creep right to the razor's edge of no 2nd stage at all - all with complete safety.

Using a Super right out of the box with a raw unpolished hammer, 1st/2nd weights of ~8oz/1lb are available, conveniently adjusted for with the gun fully assembled since the screws sit naked out in the open.
Last edited by pneuguy on December 13th, 2015, 4:33 pm, edited 1 time in total.
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Joined: July 11th, 2001, 6:08 pm

December 13th, 2015, 8:49 pm #6

Works as advertised!

Test rifle:



Trigger unit: (that light striker, weak spring, and a tiny gas port on the valve is makes this one a 4.5-5 foot pound rifle, but with 80-90 shots per 12gr.)



Used harder plastic shims in various thicknesses (mostly from 12gr shells/ wads). Not really compressible, but I didn’t have anything “squishy” in the right thickness.

No real trigger gauge, so I “cheated”.

TRIGGER PULL GAUGE CHEAT:
With rifle captured loosely between thumb and fore finger, pointed down, on top of a digital kitchen scale, the weight of the rifle is 6 pounds 10 oz. CAREFULLY and SLOWLY pulling up on the trigger and watching the scale read out, can get the weight where the sear tripped. Difference between the two would be the trigger pull.

Had worked this trigger over for smoothless and a crisp pull, so it’s starting off way-better than a stock 387/392. Never did anything about the take-up as it never really bothered me; it’s not 1st stage as there is nearly no real weight to it, but what weight it adds to the trigger pull is minor (scale claimes it is something like 1 ½ to 2 oz).

As tuned: 1 pound 8oz.

.032” shim = 1 pound 2 oz.

.054” shim = 14oz. BUT, the trigger malfunctioned about 2 out of 5 tries.

Evidently the .054" shim as a little too much. If I used a compressible shim, could just change the shim thickness by how tight the unit was attached, but as I was using firm shims, decided to back track to the .032” shim and a 1 pound 2 oz. pull. Boucned the rifle around on its butt and it didn’t fire. Will see what it turns out to be in pull (and safety) once the sear has mated up to its new angle.

May go to a "split the difference" shim thickness later.

Thanks.
nt
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Joined: May 12th, 2001, 1:29 pm

December 14th, 2015, 4:12 pm #7

...I'm sure you could find something that would work.
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Joined: December 8th, 2013, 9:24 pm

December 14th, 2015, 7:49 pm #8

Here's a quick and dirty mod' that implements an external adjustment for Benji trigger sears that, in all humility, I really don't think could be much simpler, cheaper, or easier.



Just in case it's not obvious how it works, it's kind of a don't raise the bridge, lower the river thing.

The scrap of innertube pushes the trigger housing away from the bodytube (and therefore away from the hammer), taking the sear along with it. This increased spacing reduces engagement between hammer and sear, which is then partially adjusted back out with the housing screws (screws on both sides adjusted symmetrically to maintain balance) until trigger creep suits the tastes of the shooter.

It works with both the stock sear and SuperSear, but since the stock sear is not a true 2-stage design, it's impossible to adjust away all the 2-stage creep without compromising safety. With the Super, by contrast, since it is a true 2-stage, you can.

Although the housing screws typically end up slightly offset from their countersunk holes in the body tube, as shown in the photo this is really neither visible nor (IMHO) cosmetically objectionable.



This may be of particular interest to users of my Benji' SuperSear, which is available both as part of the DIY ACP392 conversion kit (currently for sale in the Yellow Classifieds), and for sale as a separate part from a well known retailer.
Thanks Steve.. nt
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Joined: November 17th, 2006, 3:51 am

December 14th, 2015, 10:31 pm #9

Here's a quick and dirty mod' that implements an external adjustment for Benji trigger sears that, in all humility, I really don't think could be much simpler, cheaper, or easier.



Just in case it's not obvious how it works, it's kind of a don't raise the bridge, lower the river thing.

The scrap of innertube pushes the trigger housing away from the bodytube (and therefore away from the hammer), taking the sear along with it. This increased spacing reduces engagement between hammer and sear, which is then partially adjusted back out with the housing screws (screws on both sides adjusted symmetrically to maintain balance) until trigger creep suits the tastes of the shooter.

It works with both the stock sear and SuperSear, but since the stock sear is not a true 2-stage design, it's impossible to adjust away all the 2-stage creep without compromising safety. With the Super, by contrast, since it is a true 2-stage, you can.

Although the housing screws typically end up slightly offset from their countersunk holes in the body tube, as shown in the photo this is really neither visible nor (IMHO) cosmetically objectionable.



This may be of particular interest to users of my Benji' SuperSear, which is available both as part of the DIY ACP392 conversion kit (currently for sale in the Yellow Classifieds), and for sale as a separate part from a well known retailer.
Went ahead and kept playing with firmer plastic shims, but shimmed both the front and rear of the trigger assembly...not that it's better, just more "level".

Stock parts (with a little fitting) won't pass the bump test at less than 1 pound (I likely bump pretty hard) but will stand 1 pound 2 ounces.


Something I've been wondering. If Crosman has any Challenger 2000 parts...and has that lighter weight striker...might be worth a try in an air concerving MSP.
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Joined: May 12th, 2001, 1:29 pm

December 14th, 2015, 11:06 pm #10

...it's really not surprising that safety considerations limited how far you could take things.

The same limitation doesn't apply to the SuperSear for reasons already discussed.
Last edited by pneuguy on December 14th, 2015, 11:38 pm, edited 1 time in total.
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