removing metal from hammer for performance

[fisherman66]

Does it make sense to remove metal from the "shaft" part of the hammer in order to reduce light primer strikes when using reduced power springs and/or increase lock time?

The removal of the metal would need to be below the center of mass and since the hammer head is quite large that would mean most of the shaft could be "skeletonized" as long as it didn't weaken the structure to a point of failure. This has been done with automatics with success. I wonder why I haven't seen it done with revolvers.

 

[RsqVet]

I would worry about breakage obviously and frankly most skeletonized automatic hammers are of dubious value.... supposed to speed lock time yada yada maybe it makes a small improvement ... maybe not but it does not relate to trigger pull on SA guns obviously.

If you really want to make reduced power springs work in a revolver look at cylinder and slide... I believe he makes a few slightly longer than spec firing pins that are claimed to help with this and that he uses on the guns he does trigger jobs on.

 

[joshua]

A reduction in the weight the trigger springs will lighten the trigger pull, the reduction in the weight of the hammer will surely speed it up some when using the reduce weight springs. You will have to consult a gunsmith first. Is the hammer cast/case hardened, or is it machined from a block of tool steel quality material. This will dictate where and how much metal you can machine off. I like the idea of a lightened hammer due to the fact that a heavy hammer affects the accuracy when I shoot off hand. josh

 

[newerguy]

I'm sure someone will chime in who knows better, but I believe you have it backwards. A heavier (more massive) hammer carries more momentum, and is less likely to fail to ignite the primer. (It's like how light bullets carry more energy [all other things being equal] but don't penetrate as much as heavy bullets).

 

[James K]

Primer ignition requires a certain momentum, which is mass times velocity. If you lessen the hammer mass, you have to increase velocity, which means a stronger spring, not a weaker one. Further, reducing striker momentum can lead to problems other than misfires, like not enough remaining momentum to keep the primer metal from extruding back into the firing pin hole and hanging up the gun.

Fisherman, since you don't say what gun, it is hard to judge whether metal can be removed without problems or not. With a heavy hammer (e.g., Colt SAA), you could remove a lot of metal; with a J-frame Smith, the hammer is about as light as it can be to begin with, and removal of any more metal can put it into the unreliable category, as some folks who "bobbed" hammer spurs have found out.

There ain't no such thing as a free lunch!

Jim

 

[fisherman66]

Jim, I am thinking about the GP100, but more in theory right now. If I thought I could do the work myself I might be tempted to give it a shot (If an extra hammer could be found easily if I messed something up).

That brings me to the material - tool steel (no case hardening). I have thought about shimming the trigger to reduce friction. It's already highly polished. Honestly, it's a fantastic trigger pull, but I thought I'd play around with physics and see if I can improve the trigger pull even more. It does not have any reduced power springs (all factory). I've polished every mating surface.

I think hollowing out the shaft portion would allow me to reduce the spring power to the lowest supplied by wolfe or wilson combat and reduce lock time as well. (Cake and eat it to).

 

[Bill DeShivs]

Interesting ideas about physics. People rewrite the laws of physics all the time, but that doesn't mean it changes them.
Bill

 

[bcrash15]

Physics so far seems relatively correct. The only issue I would see from a theoretical standpoint is that assuming the spring remains the same, by reducing the mass the velocity will increase, BUT it will not be a linear relationship, i.e. if you cut the hammer mass in half you won't get double the speed (and so the momentum at the primer would be less). So like Jim said, you might have to go with stronger springs rather than lighter. On a small scale this probably won't matter too much, but start removing more than say 25% of the hammer mass (I'm making an educated guess on that figure), and you'll significantly change the dynamics of the hammer/spring relationship.

 

[joshua]

Fisherman66, I've been tihinking about the same thing also since I started shooting steel plates with my GP back in the day. It will be hard to find a hammer for your GP since Ruger makes it a factory intalled item only. I do have one, but I am reserving it for the same thing you are planning. Do a search on Ebay sometimes they pop up at the most unexpected time.

This looks like a GP100, but beware it does say 38 Spl so it could be a SP101.

http://cgi.ebay.com/GUN-PARTS-RUGER...ryZ73948QQrdZ1QQcmdZViewItem#ebayphotohosting

josh

 

[fisherman66]

Interesting ideas about physics. People rewrite the laws of physics all the time, but that doesn't mean it changes them.
Bill

Thanks Bill, I can't imagine a more constructive or helpful comment.

Thanks for the link Joshua. I will wait until I have a spare hammer before butchering one. I haven't decided exactly how to remove the extra material, but a honeycomb pattern is pretty strong and could be accomplished with as little as a drill press. I guess the other option is a file.

 

[Bill DeShivs]

It actually was helpful. Less mass requires more spring, not less.
Bill

 

[fisherman66]

Thanks again Bill for a helpful comment, but I believe you are incorrect for the same reason batters don't put rebar in their bats, they use (or used) cork.

For clarification, I'm only considering altering the shaft of the hammer. I want all the mass of it's head left intact.

 

[Tom2]

WEll I know you can buy aftermarket hammers and triggers with ball bearings in them to smooth up and perhaps speed up pull, for Smiths, but I don't think they do that for Rugers. Like someone else said, I don't think it really helps much in auto pistols, probably do it because they ran out of other stuff to do to make them look hitech and racy. Maybe next step will be racing stripes for guns! Lightening up the hammer itself would be the last thing I would think of on a revolver, even if I was having a full custom job done on it. Never seen it. So I guess you are gonna be the first one to try it and report back! Just remember what they said about availability of new hammers from Ruger....

 

[fisherman66]

part of an e-mail I received in response to this thread

Iowegan (from the Ruger forum) wrote this and I am told he is an authority on the GP100:

Energy is derived from velocity squared times mass. As you can see, velocity has more influence than mass. With spring-powered devices such as a hammer, you can reduce mass in non-critical areas and increase hammer velocity considerably. This has two major advantages. The lock time will be greatly reduced and the amount of energy on the firing pin will be increased. You can then install very light hammer springs and still get lock times just as fast as a factory spring with a factory hammer while having plenty of energy on the firing pin for reliable primer detonation. There are a number of patterns and techniques you can use. The critical mass portion of the hammer is the spur and above. This mass functions much like a hammer used to drive nails. The "handle" of the hammer is the area below the spur and above the fulcrum (pivot pin). You don't want to remove any metal within 1/4" of the center of the pivot pin hole, or the hammer will develop too much side play. So, any metal between that point and the spur is fair game. Ruger made the hammer very massive so you can easily reduce the weight by 25% without compromising strength. You can drill holes through the sides of the hammer or machine the hammer sides to give an "hour glass" figure when viewed from the rear. When a factory hammer is installed, you can trace the contour of the frame and remove all metal from just below the spur to the back edge. Installing hammer shims also improves this technique.
-----------------

An hourglass figured hammer would be much more pleasing to the eye, and when looking at a profile view it may not even be noticed (no racing stripes either). I don't have the machinery to do this quickly, but I think I can make a "miter box" type jig and use stones or files to remove material.

 

[Tom2]

Thanks for letting us in on what I would think is a pretty exotic hammer mod on a rev. I would think that unless you can do it yourself, instead of a professional smith, the cost to benefits ratio would be unattractive unless you have done everything else to the action. I know they used to do custom trigger spurs for target revs or bob the spurs(I have done that on a Ruger) but if he does it, lets have some pictures and maybe persuade us doubters.

 

[Jim Watson]

Randy Lee does a drastic skeletonizing of the hammer for a light DA S&W. I don't know why that would not help on a Ruger, but to tell a difference, everything else would already have to be just perfect.

 

[bcrash15]

while it is true that energy is mass times velocity squared, we have to consider which equation we are looking at.

E=1/2*m*v^2
where E is the energy delivered from the spring and is constant.
m is the mass of the hammer, v is the speed of the hammer.

If we rearrange this equation to solve for v you get that
v=sqrt(2*E/m)

running test cases, I find that by cutting the mass in half translates into increasing the velocity by about 1.4 times.

As stated above (I am assuming this to be correct) that the primer going off is measured by momentum, which is mass times velocity. So if you cut the mass by half and get the corresponding velocity increase, the new momentum of the hammer at the primer will be 70% of what it was before. Basically, since velocity effects the energy balance more than mass, it only goes a little faster to compensate for the reduction in weight.

Of course this is all simplified and hypothetical and I would bet good money the practical application varies quite significantly. For example, the location of mass removal would make a big difference, as the closer to the pivot point it is removed the less effect it would have. Overall, I would take the word of someone with experience on what you can get away with, but this is the general math behind it.