Swapping hammers in two Ruger GP-100s

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Deaf Smith

New member
While back I got a GP-100 3 inch 'C.A.I.' import. A Canadian .357.

This is the one I am looking for wood grips (and I think I'll wait till the Thiland guy has some wood form the remarks of others here!)

Just last week I got ANOTHER one. It is a 4 inch, also C.A.I. It has a DAO hammer.

BUT I want the DAO ont the 3 inch not the 4 inch.

So I tried to just swap 'em.

Works perfect on the 3 inch but not the 4 inch. Three inch GP works great and has a DAO hammer.. BUT the 4 inch, with a regular hammer, cocks single action but does NOT cock double action (aka trigger cocking.)

What gives? I looked real carefully but I find no difference in hammers except the DAO hammer has no sear leadge. The trigger groups look identical.

I notice the hammer and trigger group have a '4' magic marker number on them.

Thanks for any help.

Deaf
 
I would be very careful doing this.

Ruger does not usually sell hammers for the GP100 due to the fact that they are fitted at the factory when the gun is made. I am not surprised you are having issues. If you really want it done you can send the 4" to Ruger and have them install a standard hammer... perhaps even a gunsmith who is familiar with the type could do it as well.

Whatever you do, just be sure that you don't wind up with an unsafe action.
 
Move the hammer and trigger between the guns as a matched pair
Click to expand...

I tried that but no go.

Thing is, if I don't put in the hammer spring the 4 incher works right. Add the tension of the spring and it won't trigger cock. The hammer on the 4 incher cocks and stays cocked, so the sear is there and fits right with the other trigger.

The 3 incher works perfect. DAO all the way.

I suspect what is called the 'hammer dog' must be a bit dimensionally different. This part seems to be used on the hammer to cock the action DA. The 'hammer dog', like the hammer, is reserved to be factory fitted. So I bet it is filed down or dimensionally changed per fitting to the trigger.

It is easy to take the hammer dog out and swap... might work.. might not as it could be off a fraction.

I have a DAO hammer on my Speed Six and it swaps out with no alterations with a regular hammer, BUT the Speed Six hammer actually does cock SA.

More testing and research needed.

Deaf
 
It was the dogs!

Swapped them and they both work fine!

Now new front sight for the 4 incher and wood grips for both of them.

Deaf
 
Magnum Nike!

More on the hammer dog...

Well the DAO 3 inch GP100 kind of hesitates before the DA pull starts to cycle the action.

Once past this hesitation it functions quite well.

The 4 inch GP100 I have the swapped hammer dog in has a dream DA pull. No hesitation, hammer goes just a bit past the cylinder locking and then it drops. Just a great DA pull.

But the 3 incher, well it works, and it is quite serviceable as a DAO revolver but I'm a spoiled S&W fan and I like my DA pulls to be smooth, no stacking, no hesitation.

Ok the hammer dog yes is a bit short. Just. Also it was bent.

So I flattened it just a bit to lengthen it.

Bent you say?

Yes when flatting it on a very flat and hard surface one side would hurt my fingers when the hammer struck, the other side would not. Thus the dog was not perfectly strait.

I straitened it and the tip lengthened just maybe .002 inches.

Now there is no hesitation and the DA pull is super smooth EXCEPT the hammer drops fairly far after the cylinder is locked. That means the second part of the cam surface on the dog is a bit long and needs rounding/shortening so the hammer drops just a bit AFTER the cylinder locks up.

But that will be for another day.

Today I do the 1000 cycles I do to smooth the parts out.

Besides, Casino Royal is on.

Deaf
 
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