Lyman GPR Set Trigger Adjustment

[juano2001]

Can anyone tell me the size and tpi of the screw used to adjust the GPR set triggers. It seems all of the newer GPR's have a screw that is too short to take all of the creep out. I would like to replace mine with a longer screw. I'm guessing this may be for liability reasons??? I have about 1/8 inch of creep in mine with the screw all the way in and I find it hard to shoot like that.

Thanks

 

[john12865]

I moved up to the next size screw and tapped it out for that. I used a brass screw and trimmed it down to where I had a nice clean brake. I've done it on many with no problems.

 

[john12865]

I moved up to the next size screw and tapped it out for that. I used a brass screw and trimmed it down to where I had a nice clean brake. I've done it on many with no problems.

The original screw was a #3 if I remember correct, which I could never find. Anyway I went out to the shop and found the package of screws I use for this modification. Tap out for a #4-40x1/2 Pan Head Brass Machine Screw. Trim off to suit your needs. There should be no problem finding those screws. Hope this helps.

 

[cptleo1]

The screw is no doubt "METRIC"

 

[BrownBear]

Yup, it's metric, and sorry to tell you I can't remember the size. I took mine out and carried it into the hardware store. Found the nut that matched the threads, then went looking for a longer one. Unfortunately all are too long or short, so you'll have to buy the longer one and shorten to taste. Another sad to say- no such thing as unplated versions anywhere I've looked. I'd drill and tap if it bothered me more, but so far haven't gone there.

 

[john12865]

Yup, it's metric, and sorry to tell you I can't remember the size. I took mine out and carried it into the hardware store. Found the nut that matched the threads, then went looking for a longer one. Unfortunately all are too long or short, so you'll have to buy the longer one and shorten to taste. Another sad to say- no such thing as unplated versions anywhere I've looked. I'd drill and tap if it bothered me more, but so far haven't gone there.

Yeah, there is no doubt that InvestArms lawyered them up. It's that way on all of thier guns with double set triggers. It's seems that no matter what you do, they are going to make you at least modify a screw to remove Liability and place it on someone else.
The screw the gun comes with is a joke when it comes to having a set of double set triggers work right. :shake:

 

[john12865]

Can anyone tell me the size and tpi of the screw used to adjust the GPR set triggers. It seems all of the newer GPR's have a screw that is too short to take all of the creep out. I would like to replace mine with a longer screw. I'm guessing this may be for liability reasons??? I have about 1/8 inch of creep in mine with the screw all the way in and I find it hard to shoot like that.

Thanks

Hey Juan, Isn't just a little bit to cool to be growing coffee up there? :hmm:

 

[lanedh]

Hola--

From other posts on the same subject I recall that the original screw size for the GPR trigger let-off setscrew is a metric 2.5 fine thread, where the pitch of thread is 0.039 mm peak-to-peak (this is from the Machinery Handbook). Unless you find a store that is heavy into metric fasteners it'll be tough to find the right thread and length, so do what the other guys have done: drill out and tap for the next higher UNF machine screw--you'll find your choice of metal, finish, screw-head shape, length, etc. far wider than what's usually available in metric. Plus if it ever comes undone and falls away unnoticed it will be easier to replace.

Bluejacket

 

[nvbirdman]

Since my GPR was in kit form it was easy enough to just take the whole trigger assembly to the hardware store and find a longer screw.