Question about bobbed hammers

[Cherokeewind]

So bobbed hammers look cool............

 

What are the real benefits of bobbed vs. stock hammers?  I have several S&Ws with bobbed (Apex and my own work) and don't really see any benefit.

 

Educate me please.

 

Thanks,

Jim

[radny97]

A bobbed hammer reduces the mass that the hammer spring has to accelerate in order to strike the firing pin. Hence you can get harder and faster hammer strikes.  Thus with a bobbed hammer you can lighten the hammer spring and lighten the trigger pull while still getting reliable ignition. 
second benefit is for carry, there’s no hammer to snag on anything in your draw. 

[Cherokeewind]

Both those points are what I have seen/heard  mentioned numerous times and I understand and agree.

 

Has anyone actually measured the decrease in trigger pull or lock time with bobbed hammers vs. standard?

 

It's interesting that Apex has what they call a "mass driver" hammer for .22 rimfire revolvers, causing me to think that there is/may be a point where mass is too low to provide enough impact even with a significant increase in hammer velocity.

[MWP]

The mass driver takes the useable weight in the hammer and moves it up to hit harder- almost the opposite of the centerfire hammers. It’s specifically for 22 rimfires. 

There’s been debate for years about chopped factory hammers compared to aftermarket spurless hammers. I have shot and owned plenty of both, and both can be fantastic guns. While I do think that chopped factory hammers look unique these days, the Apex and TK options look better with the guns, close up the debris hole (which isn’t an issue if you maintain the gun.)

 

 Aftermarket hammers provide the option for people to return guns to factory condition of the gun ever needs to return to its home for a tune up, or if the gun goes up for sale. 
 

If you’re asking the difference in overall trigger weight it’s a pretty significant difference with a bobbed hammer. Also, the lightened hammers “land” noticeably softer on the frame and firing pin, causing the sights to move less after hammer impact. 
 

Some people, like myself, cannot shoot a gun with a spur on it. 

[Makicjf]

Physics aside, and for me personally, if I don't bob the hammer, the hammer spur is obstructed by the meat of my right hand between the thumb and forefinger.  I find the spur hitting my hand disrupts my trigger press and bobbles my sight picture.   Most of my DA's are bobbed flush for this reason.  The two  exceptions are my SRH 454 which just misses my hand with the hogue tamer installed (  its the only DA i shoot in single action) and my 1917.  The 1917 is the only revo I own for the sake of ownership.  I may have 500 rounds through it, but was most likely in Europe, and is , imo, the finest fighting revolver ever issued which actually saw combat.  I'm not cutting it up.  If I found a 1937 Brazil model, I'd bob it in a heartbeat and add visible bead to the awful front sight.

Jason

 

Edited March 15, 2021 by Makicjf

[pskys2]

I don't think you can find any data other than anecdotal on the differences.  Maybe someone can set up a gauge to measure the impact at the firing pin with different weight/configurations of hammers?  But even then you'd have to calculate not only force but dwell time?  If anyone could go, or has gone, to that extreme my bet is it would be Randy Lee at Apex.

 

So my anecdotal evidence is:

625PC sent to Apex where they chopped the hammer and gave it a 4 1/2# action.  Worked for most of a season then I started getting light strikes.  For me 1 in a practice session is too many.  So I adjusted the springs to bring it up to a 5 1/2# action with no issues using the same chopped hammer.  

627PC put the above hammer in and worked up a 5 1/2# action with no light strikes. 

Got a 325TR for EDC and transferred the above hammer to it with a 7 1/2# action and it lights off everything.  I don't have an issue with hammer spurs hitting my hand, but for EDC a spur is very problematic.

Put the original hammer back into the 627PC, smoothed and tuned of course, retaining the spur and with no change in the springs it still has a reliable 5 1/2# action with no light strikes.

Have a 627Pro with original hammer and I did an action job on it and it's 5 3/4# with no light strikes.  I'm sure I can get it down further with a bit more work, just don't have time right now.

625PC with a spurred hammer sits at 6#'s with no issues.  I think if I worked on it a bit more I could get it down to 5 1/2#.

 

So long story short down to 5 1/2#'s I've been able to have a reliable action with a spur.  If going below that everything gets a lot more finicky.  A slight increase in headspace or end shake due to many round fired will cause a reliable 5# action to start acting up.  Bent moon clips, excessive carbon in the chambers can in varying degrees cause an issue.  So I came to the conclusion that long term reliability was more important than a super light action and settled on 5 1/2 to 6#'s as my goal.

 

As a side note below 5# Actions seem to cause me to short stroke just as much as a 10# action.  That relay between my central computer and the trigger finger servo seemed to compute a 1911 style trigger and return.  I practiced several thousand rounds and many months and under stress the glitch would show up!  Finally decided it was better for me to focus on the fundamentals with what worked for me.  I've been happy with the results.

[mchapman]

7 hours ago, pskys2 said:

I don't think you can find any data other than anecdotal on the differences.  Maybe someone can set up a gauge to measure the impact at the firing pin with different weight/configurations of hammers?  But even then you'd have to calculate not only force but dwell time?  If anyone could go, or has gone, to that extreme my bet is it would be Randy Lee at Apex.

 

So my anecdotal evidence is:

625PC sent to Apex where they chopped the hammer and gave it a 4 1/2# action.  Worked for most of a season then I started getting light strikes.  For me 1 in a practice session is too many.  So I adjusted the springs to bring it up to a 5 1/2# action with no issues using the same chopped hammer.  

627PC put the above hammer in and worked up a 5 1/2# action with no light strikes. 

Got a 325TR for EDC and transferred the above hammer to it with a 7 1/2# action and it lights off everything.  I don't have an issue with hammer spurs hitting my hand, but for EDC a spur is very problematic.

Put the original hammer back into the 627PC, smoothed and tuned of course, retaining the spur and with no change in the springs it still has a reliable 5 1/2# action with no light strikes.

Have a 627Pro with original hammer and I did an action job on it and it's 5 3/4# with no light strikes.  I'm sure I can get it down further with a bit more work, just don't have time right now.

625PC with a spurred hammer sits at 6#'s with no issues.  I think if I worked on it a bit more I could get it down to 5 1/2#.

 

So long story short down to 5 1/2#'s I've been able to have a reliable action with a spur.  If going below that everything gets a lot more finicky.  A slight increase in headspace or end shake due to many round fired will cause a reliable 5# action to start acting up.  Bent moon clips, excessive carbon in the chambers can in varying degrees cause an issue.  So I came to the conclusion that long term reliability was more important than a super light action and settled on 5 1/2 to 6#'s as my goal.

 

As a side note below 5# Actions seem to cause me to short stroke just as much as a 10# action.  That relay between my central computer and the trigger finger servo seemed to compute a 1911 style trigger and return.  I practiced several thousand rounds and many months and under stress the glitch would show up!  Finally decided it was better for me to focus on the fundamentals with what worked for me.  I've been happy with the results.

I would assume that all of of this was with fully seated Federal primers? How much would it change if you were to use harder CCI primers. I think that is where a bigger difference would show up in the pros or cons of bobbed or not.

[MikeBurgess]

1 hour ago, mchapman said:

I would assume that all of of this was with fully seated Federal primers? How much would it change if you were to use harder CCI primers. I think that is where a bigger difference would show up in the pros or cons of bobbed or not.

you likely wont find anyone that's seriously running a revo that's not using Federals, the difference is so big. if your racing with CCI does it really matter if its a 8 or 9lb trigger? I have a couple guns that I have tuned to eat anything and in reality a 9lb trigger is not much different to run than a 6lb one

 

[mchapman]

17 minutes ago, MikeBurgess said:

you likely wont find anyone that's seriously running a revo that's not using Federals, the difference is so big. if your racing with CCI does it really matter if its a 8 or 9lb trigger? I have a couple guns that I have tuned to eat anything and in reality a 9lb trigger is not much different to run than a 6lb one

 

Oh I fully understand that about the Federals, I was just trying to answering the OP's question is there any benefit to bobbing the hammer and I think with a bobbed hammer you can run a lighter trigger to still set off harder primers vs one with a spur still on. With the primer situation these days one may have to look at what ever is available.

[MikeBurgess]

2 minutes ago, mchapman said:

Oh I fully understand that about the Federals, I was just trying to answering the OP's question is there any benefit to bobbing the hammer and I think with a bobbed hammer you can run a lighter trigger to still set off harder primers vs one with a spur still on. With the primer situation these days one may have to look at what ever is available.

totally get that, that's why my 625 was tuned for anything, I set it up during the last primer crunch. 

 

[pskys2]

16 hours ago, mchapman said:

I would assume that all of of this was with fully seated Federal primers? How much would it change if you were to use harder CCI primers. I think that is where a bigger difference would show up in the pros or cons of bobbed or not.

Yes you are right the hammer fall weight needs to be around 40 oz for SPP, on my 45 it needs 44 oz for LPP, all Federal.

I have set up and shot with varying weight hammer falls with both spurred and non-spurred hammers.  The little I've done led me to believe there was not a difference due to the type of hammer but with the weight of the fall.  It takes a minimum of 48 oz for WLP & maybe a bit more for CCI's.  And my experience at the action weights I used was that the hammer weight was secondary to the hammer fall weight.  

If I let my OCD back into getting the "ultimate action" I'd probably hack all of my hammers, or drill them out or re-shape them all after removing the spur.  But I am able to control my instincts with the feeling (for now it can always resurface) that I perform best with an action between 5 1/2 to 6 lbs.  At those rates I have a robust reset that I'm comfortable with and a heavy enough hammer fall to light off Fed Primers without fail.

Now if I start having trouble with ignition at those rates and can't get it back without upping the hammer fall significantly enough that it affected the trigger rebound, then I'd give it another thought.  FWIW my experience has been that under 5 lbs everything needs to be perfect and the chopped hammer can be that little bit extra to help.  Above 5 1/2 lbs you will have enough power that the spur is of little consequence.

I measure hammer fall by clearing the gun (of course but I still say it), cocking the hammer, placing a trigger bar from a trigger scale between the hammer and the frame, pull the trigger to drop the hammer and with the trigger still pulled back and the bar perpendicular to the frame, I pull back on the gauge until I find the balance point midway in its throw.  Then I measure the weight it takes to hold there.  That's what I consider in hammer fall weight.

Edited March 16, 2021 by pskys2

[Fishbreath]

I recently bobbed a hammer for my Super GP100. I have a cut one and an uncut one now. With the 9lb hammer spring, the bobbed hammer sets off Winchester primers reliably, whereas the stock hammer didn't.

[Cherokeewind]

It seems that hammer "weight" (light vs. heavy/bobbed vs. unbobbed) is similar to the to the light vs. heavy bullet discussion:

 

there is a middle ground between extremely light bullets and heavy bullets (extremely light hammers vs heavy hammers) where the best result are to be had.

 

Comical example:  try moving an anvil (or heavy object of your choice) by hitting it with a BB vs. hitting it with a nine pound hammer........

 

Some of my revos have bobbed hammers but most have standard hammers.  I have sorta settled on 3.5 pounds of rebound force and 7 pounds on the trigger pull gage, that means about 50 ounces on hammer fall measured with the hammer held at full cock position the trigger all the way back.

 

I want to be able reliably pop not quite fully seated Fed primers.

[pskys2]

38 minutes ago, Cherokeewind said:

It seems that hammer "weight" (light vs. heavy/bobbed vs. unbobbed) is similar to the to the light vs. heavy bullet discussion:

 

there is a middle ground between extremely light bullets and heavy bullets (extremely light hammers vs heavy hammers) where the best result are to be had.

 

Comical example:  try moving an anvil (or heavy object of your choice) by hitting it with a BB vs. hitting it with a nine pound hammer........

 

Some of my revos have bobbed hammers but most have standard hammers.  I have sorta settled on 3.5 pounds of rebound force and 7 pounds on the trigger pull gage, that means about 50 ounces on hammer fall measured with the hammer held at full cock position the trigger all the way back.

 

I want to be able reliably pop not quite fully seated Fed primers.

The hammer fall sounds right with my measures, for some reason I get a lot lower rebound force, probably not measuring it correctly though as I just started quantifying it  but then the Total Action Weight is higher than mine also.

I think the issue though is there are 4 factors to consider:

1) resistance of cartridge in chamber and any spring of a moon clip, not a consistent variable

2) hardness/compound of primer, seating depth and a crush factor combining all of those

3) impact force a derivative of mass and captured spring weight

4) Impact type a fast/quick slap vs a heavy/prolonged push, which fits exactly with your bullet analogy

So the theory is that the faster impact of a lighter hammer would overcome the crush factor of the primer quicker, basically overcoming the crush factor with less cartridge movement, than a slower/heavier hit that has enough dwell time to push the cartridge forward thereby extending the crush factor and giving more opportunities for ignition failure.  

Fishbreath's previous post on a GP100 is a good fact to consider.

This is why I consider the bobbed/lightened hammers as less of an advantage the heavier you go on the Action Weight.  And more advantageous/critical the lower the Action Weight.

Might have to take the time and play with it a bit more?  Have an excess of LPP's I could play with on the 625, and it would push me to practice more???

Yep, and when I do it this time I'm going to measure and quantify every thing!  Maybe I can find that sweet spot and move up a bit more?

 

[Cherokeewind]

I would be happy to help you solve your excess LPP problem:) 

 

I measure rebound force with only the trigger/rebound slide/rebound spring installed, attach trigger pull gage to trigger and slowly pull until the trigger reaches max travel.

 

I could reduce the rebound force at least a half pound if I were willing to give up the harder hammer hit and/or the slightly more robust trigger reset that I like. 

Edited March 16, 2021 by Cherokeewind
added info.

[pskys2]

3 hours ago, Cherokeewind said:

I would be happy to help you solve your excess LPP problem:) 

 

I measure rebound force with only the trigger/rebound slide/rebound spring installed, attach trigger pull gage to trigger and slowly pull until the trigger reaches max travel.

 

I could reduce the rebound force at least a half pound if I were willing to give up the harder hammer hit and/or the slightly more robust trigger reset that I like. 

The LPP isn't a problem it's a fallback!

I just ran a bunch of tests on the 625 my light rebound number is actually the amount of weight left when the rebound slide overcomes the hammer.  The actual rebound weight, measured like you said, was 28 oz but with the hammer installed. 

The hammer fall was 42 oz and the overall Action weight is 5 3/4 lbs.   I measured everything from the FP length to the strain screw length.  Putting it all in a spreadsheet and will play with spring weights and then repeat with the lightened hammer.

Have 2 hammers fitted for this Revolver, and both to the 325, the factory 325 hammer which is in the 625 now weighs 1.15 ounces the hammer cut down by Apex weighs .85 ounces.  As a side also had an original, 1.50 oz, and a hammer lightened by me, 1.30 oz, for a m29.  The extra weight is due to the FP in the hammer nose.

 

I'm getting excited to work on this!   Or getting bored with winter?  

[Cherokeewind]

28 ounces on the rebound spring isn't something that I think I could make work, measuring rebound spring pressure only, with the hammer removed.  I could get 

2 1/2 pounds to work, maybe.

 

My lightened N frame hammer, with Power Custom extended hammer nose, weighs exactly 1 oz.

Edited March 17, 2021 by Cherokeewind

[pskys2]

13 hours ago, Cherokeewind said:

28 ounces on the rebound spring isn't something that I think I could make work, measuring rebound spring pressure only, with the hammer removed.  I could get 

2 1/2 pounds to work, maybe.

 

My lightened N frame hammer, with Power Custom extended hammer nose, weighs exactly 1 oz.

No doubt with a 50 oz hammer fall as both weights need to be balanced to ones preferred feel.  At 42 oz hammer fall and a 28 oz rebound there ends up being a 6 oz weight as the hammer resets past the rebound slide and the bolt lock.  It is still a very positive return, I can actually dial up the same set ups hammer fall to 52 oz before the trigger won't reset.

 

By the extended hammer nose do you mean the old style hammer with the FP attached?  Or does/did Powers make a new style with an extended nose to impact the frame mounted FP?

My Factory frame mounted FP Hammers are .35 oz lighter than the Hammers w/FP attached.

Edited March 17, 2021 by pskys2

[Cherokeewind]

The hammer I referred to is the old style with attached FPin.....S&W calls it the "hammer nose".

[pskys2]

1 hour ago, Cherokeewind said:

The hammer I referred to is the old style with attached FPin.....S&W calls it the "hammer nose".

I figured, but didn't recognize the nomenclature.

I took one from a M28 and it weighed 1.50 oz

one I cut down for a M29 and it weighed 1.30 oz

Factory 325PC was 1.15 oz

Apex cut for a 625 was .85 oz

 

I've been told the older style with a "nose" are harder to get below 7 lbs, had an Action Job done by Clark on a M29 and it came back at 7.5 lbs, felt good too.  I've been able to get the M28 down to about 6 1/2 lbs, but never pushed it to see how low I could go.  

[Cherokeewind]

Power Custom makes longer firing pins for those old style hammers but they require a bit of work to remove the old pin and install the new one. 

 

6 1/2 pounds isn't so bad:)

Edited March 17, 2021 by Cherokeewind
added info.

[PatJones]

18 hours ago, pskys2 said:

I've been told the older style with a "nose" are harder to get below 7 lbs, had an Action Job done by Clark on a M29 and it came back at 7.5 lbs, felt good too.  I've been able to get the M28 down to about 6 1/2 lbs, but never pushed it to see how low I could go.  

 

My old 625 "Model of 1989" is running at 6.25-6.5, no special treatment. It still has its hammer spur too.

 

If need be, you can adjust hammer nose protrusion by filling the face of the hammer slightly.

[pskys2]

12 hours ago, PatJones said:

 

My old 625 "Model of 1989" is running at 6.25-6.5, no special treatment. It still has its hammer spur too.

 

If need be, you can adjust hammer nose protrusion by filling the face of the hammer slightly.

All of my current competition & EDC Revolvers are frame mounted FP's.  Have a M28 6" and a M29 4" but I rarely shoot them.

[PatJones]

2 hours ago, pskys2 said:

All of my current competition & EDC Revolvers are frame mounted FP's.  Have a M28 6" and a M29 4" but I rarely shoot them.

My every day J frame is a model 60 ladysmith; No lock with a hammer nose mounted on bobbed hammer. I've not really tuned anything on it, the trigger pull is fine as is.

[pskys2]

11 hours ago, PatJones said:

My every day J frame is a model 60 ladysmith; No lock with a hammer nose mounted on bobbed hammer. I've not really tuned anything on it, the trigger pull is fine as is.

Have a 442 (took out the lock) & a Taurus m85 all I've done to either was a little smoothing.  For the distance and need factory pulls on them are fine.  They actually feel good and smooth, just over 10 lbs.  

Now mostly when I EDC a Revolver it's the M325 Thunder Ranch and that one I smoothed up and lightened the rebound spring, think it's 15 pound, and it feels real good.  So good I like to shoot it in IDPA, when I do shoot there, the Action on it came out at 7 1/2#.  Something comforting about 6 big ol' 45 230 grain slugs.