GPR Trigger

[longcruise]

This has been on my bench for many months. Otiginally planned to go into my stand by big game rifle, a GPR that I built back in 1982. I have always disliked the GPR set trigger and so the plan was to build a single trigger and fit it to the rifle in such a way as to allow interchangeability between the factory set trigger and the single trigger. The factory set trigger is fine for firing in the set position but is terrible to the point of useless to fire unset. All the GPR triggers I'm familiar with had unset trigger pulls ranging from "simply won't fire" to a 15 or 20 pound pull.

Since I'm in the process of building another GPR kit, I decided to fit it to the new rifle rather than the old. Since it is a drop in, it will probably work in both but I've not tried it in the older gun yet. I'll probably build another for the older gun.

So, here it is in all it's rather ugly and unpolished glory. Trigger pull is about two pounds and should be good for hunting and targets. The top set is the factory set trigger

 

[BrownBear]

Boy, I wish you'd start turning those out in volume, or inspire Davis to follow your lead! :hatsoff:

 

[longcruise]

I thought about that, then decided that making a few of these is very satisfying but making them in quantity could be pure drudgery! There is also a potential problem in getting a universal fit. I'll know more after trying this one on a few other rifles.

The sear arm on the lock this one fits jumps around a lot from 1/2 cock to full cock. There could be considerable variation from lock to lock which would require quite a bit of adjustment for each fitting. Course in this case, "adjustment" means hand filing.

 

[kurts]

could a set screw be used through the post for trigger adjustment?

 

[longcruise]

Do you mean overtravel as in a trigger stop? I'm not sure of your actual question

 

[kurts]

if you came in from the front it could be a trigger stop and could raise or lower the trigger against the sear. just thinking out load.

 

[longcruise]

I see now. And, yes that could be done. However, there is very little play there, maybe an 1/8". In this case, such a stop could be used to reduce that play to near zero because the movement of the sear arm is continuously downward as the hammer is drawn from the down position through half cock and into full cock. IOW, the stop.you describe would not interfere with cocking the hammer.

Another thing that could be done is a spring wire could be placed behind the trigger (on the butt end of the triggerplate) to raise it into continuous contact with the sear arm.

 

[ohio ramrod]

I have often used guitar "string" wires to remove slop from single triggers. It is a simple thing, Just find the right location, drill a hole the proper size and fit the spring in, red locktite will work, But if you are careful you can solder the spring in place with out out drawing out the temper. :idunno:

 

[vulture]

I too dislike the set triggers on my GPR and have tried finding a single trigger that would work as I am putting together a GPR flint kit at this time, never could find one that would fit and work satisfactorily, and I don't have the skill to build such as you have, so I simply ordered a replacement set trigger from Davis, fits great and much better than Lyman original, but it is still a set trigger and I am one of those folks that simply prefers a single non set trigger, odd man out in many cases, I also like triggers that have the same type of creep built into military rifles, don't ask me why, just do a lot better with them.

 

[longcruise]

If you simply want the single trigger with no concern for changing it out, you can just pin it through the wood. locate the trigger, make a trigger plate and pin it.

The trigger in mine is a Leman trigger as sold by Track and other suppliers. It requires reshaping with files and hack saw but is not very difficult.

I'm finding that making triggers and sights is addicting.

 

[Crewdawg445]

That looks very swell, I actually did the same thing, only I utilized the stock trigger plate by tacking all the holes minus the front trigger, filed the whole assembly down smooth concealing all traces of the previous holes. Then made my own single trigger from 1/4" mild steel plate. Turned out exceptionally well and certainly makes a dramatic difference! Thanks for sharing! :hatsoff:

 

[longcruise]

I was tempted to do that, but I don't plan on keeping the rifle. I'll give it to one of the kids or sell it. Today I contemplated the purchase of an investarms Cabela's Hawken. Tried the front trigger unset and it functioned at about 3# still might go back for it. A good project gun and would make a dandy elk rifle.

 

[Crewdawg445]

Love those little project guns! I currently have more disassembled on my bench for browing, metal work and wood work than I can handle!

 

[longcruise]

I know what you mean. Too many of my projects have been laying on the bench for years!

 

[LRB]

Much of the problem of a heavy unset trigger pull is in the lock. Most often a lock can be re-worked to give a decent unset pull weight. This usually involves a lighter sear spring, polishing, and installing a screw, plate, or pin below the tumbler notch to lesson the amount of sear engagement. This also allows the set trigger to be adjusted to lighter spring pressures making the set pull even lighter, If wished, and making both the lock and triggers more quiet in operation while hunting, if one hunts using a set trigger as I often do.

 

[BrownBear]

Much of the problem of a heavy unset trigger pull is in the lock.

With the GPR and Investarms in general, a simple trigger change takes care of it, making me think it's more the fault of the trigger than the lock. The RE Davis Deerslayer trigger is supposedly for TC's but is a drop-in with the Lymans I've used it on.

My first attempt sold me forever. That GPR had an unset trigger pull of right at 12 pounds. Dropped in the Deerslayer and the pull was instantly 2.5# and crisp as a set trigger. Wow.... Much the same for all others I've switched.

Not being a metal worker, I'd be tempted simply to try gutting the Deerslayer, removing the rear trigger and good riddance. Dunno if that's feasible. Unset, the front trigger is so good I never use the set trigger anyway, so I wouldn't miss it.

 

[LRB]

There would be nothing wrong with removing the rear trigger, if you want. Just remove the spring and drive out the pin holding the trigger in place. I still stand by what I posted. The only difference I see between the stock triggers and the Davis, other than the Davis parts being very likely smoother, is that the action bar on the front trigger is much higher on the Davis, and the trigger itself is straight and longer. I would assume that probably gives a geometric/mechanical advantage over the stock triggers, but extra metal could be added to the stock trigger also. I believe that a work over of both the lock and triggers would produce a very sweet set up.

 

[BrownBear]

I believe that a work over of both the lock and triggers would produce a very sweet set up.

I bet you're right! I just don't have the skills/welding equipment, etc to do it. I'm just delighted that the Davis trigger works so well.

Thanks for the word on removing the set trigger, too! The way it sits so far back against the guard, it isn't any trouble. Just seems superfluous most of the time.

Thanks for the comeback Wick! Informative and rational as always. :hatsoff: