Swapping hammers in two Ruger GP-100s

[Deaf Smith]

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

 

[Panzerschwein]

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.

 

[Drail]

You cannot "swap" parts from one gun into another. They are fitted to an individual frame.

 

[GP100man]

On GPs it is possible & not unheard of to "drop in" a hammer , on the other end it`s possible to get a hammer where the sears are to short at the sears & won`t work never.

The chances of getting a bubba`ed hammer is also hi.

I`d also advise to let Ruger fit you a hammer .

 

[mavracer]

Did you try swapping the trigger too?

 

[rcmodel]

IMO:
If you haven't already?

Put the parts back where they came from before you screw them all up!!

Hammers & sears are already worn into each other through use.

No good can come of swapping them around now.

rc

 

[Deaf Smith]

Did you try swapping the trigger too?

Yes. Tried that to.

But the schematic shows a 'hammer dog' that enguages the trigger for trigger cocking.

It is easy to get out and swap just that part. Youtube has several 'how to' ruger videos.

I also noted that Ruger won't sell 'hammer dogs' so I bet that part is stoned or filed down to enguage the trigger.

It cockes fine SA and the sear catches the hammer solidly. It's only DA that the trigger won't cock the hammer.. hence the 'trigger dog' part.

I also note that without the hammer spring it cocks fine DA. That also indicates the 'trigger dog' may be at a bad angle for this particular trigger group.

I'll swap dogs tomorrow.

Deaf

 

[Deaf Smith]

NIKE!

It was the dogs.. swapped them an they both work fine!

Now new grips and a new front sight for the 4 incher.

Deaf

 

[mavracer]

love it when a plan comes together

 

[Jaymo]

I bought my GP a few years ago and had to replaced a bubba'd hammer and trigger.
I ordered the parts from Numrich.
It was a drop-in swap with no fitting required.
Just like the SBH hammer I put in my .45 Convertible BH.

 

[Drail]

I have had several well used GP 100s on my bench for repair - the complaint was DA pull had a hiccup in it while the SA pull was good. In most cases the hammer dog was the issue. If it wears just a tiny bit short the DA pull will start hanging up. I have actually temporarily fixed several of them by peening the hammer dog just 5 to 10 thous. longer. I got my wife's GP 100 to last until the summer match season was over by stretching the hammer dog - hers is a first year production GP with a LOT of DA miles on it. I believe that Ruger will sell you a new hammer dog if yours is worn but not hammers or triggers. It will most probably need a tiny bit of fitting for a smooth DA pull. I was not aware that Numrich still sold Ruger factory parts. Good to know.

 

[Deaf Smith]

More on the hammer dog...

Well the DAO 3 inch GP100 kind of hesitates before the DA pull cycles the action.

Once past this hesitation it functions quite well.

So on the hammer dog does one have to take off or re-angle it to make the hesitation go away?

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.

So any ides on that?

Thanks,

Deaf

 

[Old Fuff]

Your problem may be that the "dog" is too short, and taking off more material won't help. Order a new one and fit it, or better yet, send it back to Ruger with the currently installed hammer. They just might fix it on their dime.

Keep in mind that pre-1970 Colt's, Smith & Wesson and Ruger revolvers are not based on drop-in parts.

 

[Deaf Smith]

Thanks but the GP-100 wasn't even manufactured till 1986 on out.

This one was made in 1990.

I wouild think if it was to short then it would not even catch or cycle.

Thanks anyway.

Deaf

 

[Old Fuff]

This one was made in 1990. I would think if it was to short then it would not even catch or cycle.

And from the beginning to (as far as I know) now the dogs (S&W calls this part a "sear) are hand fitted. You can get a tolerance stack in different frames - or in Ruger's case the trigger module - and almost right isn't good enough. It can be slightly short but still function and have the "bump" you describe. If shorter yet the action will jam.

In a Colt or S&W you can pop the side plate and see what is going on, but this isn't the case with Ruger's because they don't have a side plate. Because of the way they are designed Ruger frames are stronger (all other things being equal) but they're disadvantages and you have discovered one.

 

[Deaf Smith]

Magnum Nike!

Ok the hammer dog yes was 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