Friday, July 14, 2017

Troubleshooting a Hawes Western Marshal Revolver

This gun was the focus of an earlier post, see it here

I was asked to take a look at this gun by a friend, he finds good deals on broken guns now and then and this one had some issues. After shooting the gun, he discovered that it would lock up after only firing a few rounds.

I did some online research into these guns and I could not find a whole lot of info. I found many detractors and also nearly as many fans, but no one who was experiencing the same problem this gun was displaying.

I took the gun out to my favorite outdoor shooting spot and test fired it with some hand loaded 44 Specials, 44 Magnums (both light and heavy) and some factory Speer 240 grain JHP Hunting ammo. I was unable to produce the problem described by the owner.    

As he described it, the problem was that the revolver tended to lock up after firing a normal power .44 Magnum cartridge. The only way to get the gun "unlocked"n was to remove the cylinder base pin and remove the cylinder.
My first step was to look at the design of the firing pin
The Hawes with the hammer down:

The Hawes has recessed cylinders but also it has no transfer bar safety system.

The firing pin on the Hawes is spring loaded (that's a good thing) and the hammer rests on it when it is down (that is a bad thing). When the hammer is down you cannot fit the cylinder into the frame:

While inspecting the gun I thought about what could be causing the firing pin to stick out so far when the hammer is at rest.
I looked at the place the hammer strikes on the frame, it appears dished out and worn, perhaps the metal has been bashed in enough that the hammer his now sitting closer to the firing pin than originally designed? Or maybe the firing pin needs to protrud so much due to the cylinders being recessed?

My second thought was that the firing pin spring has become too weak to hold the firing pin off of the cartridges. Once the gun is fired the firing pin does not want to come loose from its new home in the soft primer. That doesn't explain why the hammer would refuse to move backwards though.
I checked the bolt stop, it functions like a Colt, after firing, if the hammer is pulled, the bolt stop retracts. So the firing pin and bolt stop would not prevent the hammer from being cocked after firing a cartridge. 
I also checked the action, as the hammer is pulled back the firing pin retracts before the pawl engages the cylinder ratchet.....
It could be the pawl, which is attached to the hammer and retracts when the hammer is pulled reward.
This could be the source of the problem. Because it is directly connected to the hammer, if the pawl is stuck, so would be the hammer. The pawl seemed to be functioning fine and the gear on the cylinder showed no signs of excessive wear.

I walked away from the gun for a while and it occurred to me...It could also be the cylinder base pin. The cylinder base pin not only keeps the cylinder in place, it also aligns the cylinder with the other parts, if it is worn or poorly fitted, the cylinder, under recoil could move, causing the pawl to stick in the gear. These guns use a bushing that fits between the cylinder and the pin (like a Colt SAA), perhaps this bushing is worn out or doesn't fit quite right?

I checked the fit of the cylinder base pin, the pins fit was tight in the bushing and the bushing was tight in the cylinder. 
The cylinder did have some pretty decent end play. When pulled back against the spring pressure of the pawl, I could slip a .019" feeler gauge into the gap.
With the .019" feeler gauge in the gap, the gun would lock up solid, you could not move the hammer rearward. It appears that this may be the problem. The base pin bushing does have a "nose" on it that appears to act as the end play bushing and these must be fit to the gun.

I pushed the cylinder as far forward as I could and the largest feeler gauge I could fit in the gap was a .0025, which is pretty tight. The end play is the difference, .019"-.0025" is .0165".

I think the correct answer to this problem would be to get a new cylinder base pin bushing that is over-sized and fit it to the gun. That may be impossible as new parts for these guns are pretty rare.

Perhaps a Colt bushing could be machined to fit?

I'll update this post if we find the cure to the problem.