Blackhawk trigger not fully resetting

[Yosemite Sam]

I've got a SBHH that won't quite fully reset the trigger. After the shot the trigger returns most of the way, but is still held back slightly from it's "home" position. If I lightly draw or even just touch the hammer the trigger returns fully forward.

I'm pretty sure it's not the trigger return spring, as I get the same results with one leg off the stud or installed correctly. It's almost as if there's tension on the mechanism, or a burr.

Any ideas what area(s) to look at?

-- Sam

 

[flatgate]

The plunger in the tip of the base pin pushes the transfer bar out and away from the firing pin.

The notches or "steps" on the hammer's face will block the transfer bar from moving up but not down as is the case when the trigger retracts.

All of this babble leads me to suspect your Hunter is suffering from "transfer bar pinch". The force of the mainspring is pushing the hammer against the transfer bar and not permitting the trigger return spring from pushing the trigger forward which also retracts the transfer bar.

So, on MY GUNS I've found a simple solution. First, a test. Unload gun. Check again that it's unloaded. Now cock the hammer and then dry fire and keep the trigger held to the rear. Now, carefully watch the hammer as you slowly let the trigger return to it's "at rest" position. As the transfer bar retracts down into the hammer well you'll probably see the hammer move forward slightly as it clears the "notch" on the hammer's face. On MY GUNS I've increased the depth of that notch so that the hammer does NOT move one bit as the transfer bar is retracted. A thousandth or two of clearance won't effect the firing pin's job since it's smacked really hard and has plenty of inertia to fire a cartridge. All parts are smoothed out in the interest of reducing friction. This procedure also stops "transfer bar" breakage due to dry firing the New Model Revolvers.

The above is MY THEORY and is provided here for Entertainment Purposes ONLY and IS NOT RECOMMENDED to be performed on any Ruger New Model revolver.

flatgate

 

[Yosemite Sam]

Thanks, Carl. I'll take a close look at that.

But, as you did the other day, you've given me a big, fat hint to look at: The base pin. It's a Belt Mountain pin, and was installed prior to my ownership. I never realized that function was part of the pin's role in life. Rumor has it this pin was installed by a 'smith, but I'll take a look at all of that fitment.

-- Sam

 

[tek4260]

The plunger in the tip of the base pin pushes the transfer bar out and away from the firing pin.

The notches or "steps" on the hammer's face will block the transfer bar from moving up but not down as is the case when the trigger retracts.

All of this babble leads me to suspect your Hunter is suffering from "transfer bar pinch". The force of the mainspring is pushing the hammer against the transfer bar and not permitting the trigger return spring from pushing the trigger forward which also retracts the transfer bar.

So, on MY GUNS I've found a simple solution. First, a test. Unload gun. Check again that it's unloaded. Now cock the hammer and then dry fire and keep the trigger held to the rear. Now, carefully watch the hammer as you slowly let the trigger return to it's "at rest" position. As the transfer bar retracts down into the hammer well you'll probably see the hammer move forward slightly as it clears the "notch" on the hammer's face. On MY GUNS I've increased the depth of that notch so that the hammer does NOT move one bit as the transfer bar is retracted. A thousandth or two of clearance won't effect the firing pin's job since it's smacked really hard and has plenty of inertia to fire a cartridge. All parts are smoothed out in the interest of reducing friction. This procedure also stops "transfer bar" breakage due to dry firing the New Model Revolvers.

The above is MY THEORY and is provided here for Entertainment Purposes ONLY and IS NOT RECOMMENDED to be performed on any Ruger New Model revolver.

flatgate

Good theory! Has worked quite well on several of mine. Especially the ones with Bullseye trigger springs.

 

[Yosemite Sam]

The plunger in the tip of the base pin pushes the transfer bar out and away from the firing pin.

That was the ticket, thanks!

This gun has a Belt Mountain base pin, with the set screw. Whoever installed it drilled the divot for the set screw about .005" too close to the cylinder, so when you tighten the screw it pushes the pin in so far it causes "the pinch".

I'm going to try running it without the set screw for a while.

Thanks again for the hint/tip!

-- Sam

 

[flatgate]

Sam,
You did a good job of investigating!
Good News!
flatgate

 

[Yosemite Sam]

Indeed, this was the problem. Unfortunately, I found that my gun will "jump the pin" with heavy loads if the set screw on the pin is not used.

What I've done at this point is to only tighten the set screw far enough that it engages the edge of the divot in the barrel. This seems to work for now, but I'll have to keep my eye on it. Worst case I'll have to have that divot elongated so that the pin will sit far enough back. Either that, or start filing on the pin, which I don't think will work.

I might also pick up a new, heavier spring for the base pin latch.

-- Sam

 

[Aggie01]

IMO, the set screw is a halfway solution. It's too easy to bind a base pin trying to get a firm hold with just a set screw.

I order my base pins from Kelye either with no screw or a bowen type screw. My base pins with no set screws get wolff extra power latch springs. The big boomers (44 mag/heavy 45 colt and up get the bowen locking screw and the base pin latch is just for show after that.

 

[Quarterbore]

Interesting! I sold a 44 Hunter on the board and my buyer is having the same issue. I know the gun had worked fine for me BUT I also swapped the Hunter grip frame from a 45 Colt Hunter with this 44 and while I dry fired it a couple times I didn't take it to the range or shoot it a lot!

Now, I need to look at the transfer bar from the original gun as I am wondering if that original transfer might have been relieved to address this issue? I had kept all the grip frame components consistent and assumed that would be the best way to ensure everything worked on the swapped guns but now I am regretting that decision some.

Kind of ironic that this issue shows up for the OP at the same time I hear that there was an issue with the one I sold and I assume we are talking about different guns, right?

 

[Yosemite Sam]

Interesting! I sold a 44 Hunter on the board and my buyer is having the same issue. I know the gun had worked fine for me BUT I also swapped the Hunter grip frame from a 45 Colt Hunter with this 44 and while I dry fired it a couple times I didn't take it to the range or shoot it a lot!

Now, I need to look at the transfer bar from the original gun as I am wondering if that original transfer might have been relieved to address this issue? I had kept all the grip frame components consistent and assumed that would be the best way to ensure everything worked on the swapped guns but now I am regretting that decision some.

Kind of ironic that this issue shows up for the OP at the same time I hear that there was an issue with the one I sold and I assume we are talking about different guns, right?

Funny! I did buy my SBHH from a board member, but it was way back in '07. Also, mine's a Bisley.

Just as an update, I have installed an extra power latch spring, but I haven't shot it yet.

Out of curiosity, why are Belt Mountain pins considered "better" than stock? I think I've heard them referred to as oversize; If that's the case, in what dimension?

-- Sam

 

[Quarterbore]

The over sized pin does tighen up the play around the cylinder. It was noticeably on the 44 Bisley Hunter (that I converted to Std Hunter) as my 45 Hunter has some movement that the over sized pin the the 44 did not demonstrate.

The guy I sold the 44 Hunter to said he found that by not using the set screw the problem went away for him too so my assumption is that very small amounts of torque or extra length is the issue as speculated here. I was planning to send my 45 Hunter out and have the cylinder chambers checked and have one of these over sized pins fitted and installed but now I am just a bit unsure.

The one in the 44 I had sold was on there from a previous owner as I had bought the gun used to start shooting big bores and finally decided I wanted to stick with 45 Colts as I just have so many yet I preferred the Bisley Hunter so I did the grip frame swap never expecting this issue.

In my case, I know I swapped the parts that could have caused the issue and it frustrates me a bit that I didn't catch it but my buyer is still happy and doesn't want to return it so just trying to learn here for you, myself, and the new owner of the 44 Hunter I had sold.

 

[flatgate]

FWIW, the locking base pin design should not create any sort of bind. The base pin lock screw should "float" in the recess hole in the barrel and not be jammed against the barrel.

The oversize Belt Mtn. pins are slightly larger in diameter which will "take up" some of the inherent "slop".

JMHO,

flatgate

 

[Yosemite Sam]

FWIW, the locking base pin design should not create any sort of bind. The base pin lock screw should "float" in the recess hole in the barrel and not be jammed against the barrel.

The oversize Belt Mtn. pins are slightly larger in diameter which will "take up" some of the inherent "slop".

JMHO,

flatgate

Ah, well then, that solves my problem right there. I just assumed it was supposed to be tightened down, which in my case, causes the pin to move rearward enough to pinch the transfer bar.

-- Sam

 

[Quarterbore]

Solves my issue too! I had not messed with the set screw when I was originally shooting the one I had and when I swapped the grip frames I had tightened it down a bit. Mike, who has the gun now, confirmed that he also had tighened the set screw down and when it was loose the issue went away.

The directions for the Belt Mountain Base pin was sent to me by Mike and it is here:

http://beltmountain.com/bowen_install.htm

From the directions:

Please notice, the screw is extra long, and the shank must be filed down until the head of the screw seats firmly into its recess in the Base Pin. The shank of the screw should fit into the drilled recess, but not bottom itself in the recess. This will cause pin bending and the screw will loosen up quickly.

So, is the issue here that both of these guns need to have that set screw shortened just enough that it can be snugged down without the screw bottoming out in the divet in the barrel?

That is the way I read these directions. Now, the base pin on the 44 Hunter I sold was a different looking pin but you can see it here:

In that case, I do not know if that set screw is the same diameter as the hole that is drilled and tapped through the base pin and if so then obviously this model can not be shortened and it would just need to be tightened and then backed off some 1/2 turn or so...

Thanks for the education, when I first got the e-mail indicating that he was seeing something strange I was some perplexed and fealt really bad as I sure had not seen the issue but I was a bit ignorant on how these work too!

 

[Yosemite Sam]

Further, based on really looking at how this is put together, and some experimentation, I believe the base pin needs to float a bit. You don't want it to be a binding force in the action. On my SBHH with BM pin, if I push the pin all the way in and hold it with a finger, then let the hammer drop, quite a bit of force is transferred to the pin. (Ask me how I know...) If the pin can't move, this force will be transferred to something else on the firearm.

I noted that my base pin latch was badly worn from all the pin jumping. I wonder how much force this part regularly encounters from that floating pin, and will now be inspecting it annually or so on all my SAs. You don't want a hardened part, as this would transfer the wear to the frame.

I also wonder about the longevity of the divot that's drilled into the barrel to accommodate the tip of the screw. If it's bashing the screw into the edge of the divot it's going to wear over time.

-- Sam