Why the Apex Hammer?

[TheBrick]

• I was never one to believe that bobbed/lightened hammers made much of any difference in a S&W revolver's trigger pull.

I was recently gifted an Apex Evolution IV n-frame hammer and fitted it to my 627 USPSA gun.

First, it weighs 355 grains against a friends S&W hammer (self bobbed and lightened) at 317 grains. If less weight is better, why all the praise on the Apex hammer?

Second, after fitting and testing for reliability; the Apex hammer required the same mainspring weight which did nothing to lighten the trigger pull or feel on my 627.

I'm not knocking the Apex product, I am just trying to understand why there is so much claim of improved performance.

I am a revolversmith of some note in the 1980's with PPC guns so I am confident that my fitting the hammer and tuning the gun is not at fault.

Anybody else have a similar experience with bobbed/lightened hammers vs Apex Evolution vs Factory in performance. 

Any suggestions in fitting/tuning that may have evolved since my smith days?    

[Toolguy]

In my experience, the Apex or the bobbed hammer at the same weight, or less, will give a lighter action than a stock hammer. I think this is due to the lighter hammer needing less spring tension to get it up to speed in the time available. Most of my guns are reliable with firmly seated Federal primers at 6 to 6-1/2 lb. DA with just the spur cut off. I have a PPC gun with an Apex hammer that is reliable at 5 lb. DA. You don't mention the pull weight of your action so it is hard to compare. When I was shooting PPC in the 1980s we thought an 8 lb. DA was the best ever. I have been building my own custom S&W revos for over 30 years. I don't do them for anyone else though, so I am an unknown in the gunsmith world. I can get a 100% reliable (with Federal primers) 6 lb. action on most any K,L, or N frame without too much effort.

[Ty Hamby]

Understand also it is not about actual weight as it is about the mass at the tip of the hammer. Many bobbed jobs leave too much mass at the top. It is all about acceleration of the hammer. While your buddies hammer may be lighter, the real question is how fast does it rotate from a dead stop. How fast does it accelerate. Like with a golf swing, its all about the club speed not as much about the muscles behind it. Apex and Carmonized hammers are the fastest accelerating hammers, which translate to the lowest possible trigger pull weight possible. 

 

Edited August 23, 2016 by Ty Hamby

[GMM50]

It's actually all about rotational inertia.  That considers where the mass is located with respect to the pin the hammer rotates about.  Mas at the tip of the hammer is different that same mass near the center of rotation.  50 years ago I could almost do the math but now I bet there;'s an app for that.

https://en.wikipedia.org/wiki/Moment_of_inertia

It's OK to Buzzer me.

Edited August 23, 2016 by GMM50

[8shooter]

I put one in my 627 38 Super and was able to wind the trigger down about 1lb and still have 100% reliability. Someone might be able to correct me if I'm wrong but I think the Apex actually changes the trigonometry of the hammer fall from the factory one.

[MWP]

TheBrick, what firing pin are you using when comparing the different hammers? Of course I'm assuming fulling seated (smashed) federal primers. And also, what weight are you finishing with? 

[TheBrick]

Thanks for all the feedback. Some interesting points are taken with "rotational speed" and acceleration vs weight.

   I never liked the "soft mushy" feel of 6 lbs. and under on revolver triggers so I set mine to right around 7 lbs. Strangely, it remains right at that same pull when I use the Apex, factory unbobbed/lightened and with my friends bobbed and lightened hammer. Just doesn't make any difference it seems in order to get reliability. I also adjust the rebound spring up and down as needed to get reliable return as the mainspring is tightened/loosened to get ignition.

     I use nothing but the Apex extended competition firing pin with their lighter return spring and firmly seated Federal primers for all my revolvers..

I will try and bend different mainsprings but I wonder if it is worth the effort for a 1/2 to 1 lb lighter trigger.

Stuck at 7.

[Toolguy]

You can bend the mainspring in the middle with a gradual curve, then use a longer strain screw or a #8-32 x 1/2" setscrew with blue loctite. Caromoney's mileage may vary, but I have never had a problem in many years. On mine, I do an S bend with gradual curves. The object of the game is to get the hammer stirrup as nearly horizontal as possible. It is normally going up at about a 45 degree angle. By putting bends in the spring, we are effectively shortening it's vertical height, which in turn brings the stirrup down with it. All this puts a lot less downward pressure on the rebound slide which allows us to have a lighter rebound spring that is still snappy in the return direction. It also allows us to have an even heavier hammer fall while at the same time, a lighter trigger pull.

Doing this, with my proprietary rebound spring and a couple of other tweaks makes it pretty easy to get a reliable 6 - 6.5 Lb. DA on any K,L or N frame. Every gun is different, so no 2 actions are exactly alike, but they can be very close to the same,

[TheBrick]

Toolguy,

That is really good information and with an explanation as to why.

Thank you for being so specific and sharing this with me. 

[Toolguy]

You're welcome Brick! I have spent 30+ years getting this figured out. All the Best - Warren

[Carmoney]

Loctiting an untightened strain screw in place will work fine.....right up until it doesn't!

[TheBrick]

Update on the Apex hammer!!!!!

     My reliability testing was faulty! Not being at the range, I was using sized and primed brass and chambering one at a time without being in a clip. Problem is that the chambers are heavily chamfered which results in headspacing problems. DUH! Stupid is as stupid does.

     Anyway, at the range today I tested all 3 hammers in the same revolver, factory standard, bobbed lightened factory and Apex Evolution using clipped live ammo.

RESULTS: The factory hammer was reliable with the strain screw set as a starting point for the other 2 hammers. 7lbs trigger pull.

     Factory lightened hammer was reliable with the strain screw backed out 1 full turn!     6 1/4 lbs trigger pull.

     Apex hammer was reliable with the strain screw backed out a full turn and 3/4.!!!  5 1/2 lbs.

No mainspring bending was used in this test so I truly believe that a reliable 5 lb trigger pull is within easy reach.

     APEX HAMMERS RULE

After believing for  26 years that bobbed hammers do not make a difference, I have now seen the light. I have also learned something about revolver smithing that was staring me in the face for all those years.

Carmoney, I never locktite a backed out strain screw. They are cheap enough to buy and cut to length when seated firmly in addition to blue locktite.

Thanks for all the help and input.

 

[Toolguy]

Way to go Brick! Thanks for sharing that info. I think it will be of value to many.

 

While we're on the subject, here's an easy way to make a strain screw longer. Chuck the screw upside down in the drill press and file the bottom of the head while it's spinning. Do a little at a time and check your progress until you get what you want.

Edited August 24, 2016 by Toolguy

[seanc]

On 8/22/2016 at 8:57 PM, Ty Hamby said:

Understand also it is not about actual weight as it is about the mass at the tip of the hammer. Many bobbed jobs leave too much mass at the top. It is all about acceleration of the hammer. While your buddies hammer may be lighter, the real question is how fast does it rotate from a dead stop. How fast does it accelerate. Like with a golf swing, its all about the club speed not as much about the muscles behind it. Apex and Carmonized hammers are the fastest accelerating hammers, which translate to the lowest possible trigger pull weight possible. 

 

Yeah, I think this is the part that is not well understood.    It is power/wattage, force applied very quickly, that sets the primer off with an otherwise very light action.   Its the abiility to get the hammer to high speed that matters.

 

I believe in days of yore, Randy used to post on this forum and if you dig around in the search I think he posted here explaining...

[Tom E]

34 minutes ago, seanc said:

Yeah, I think this is the part that is not well understood.    It is power/wattage, force applied very quickly, that sets the primer off with an otherwise very light action.

No, it's velocity. A llghter hammer can achieve the required velocity with less hammer spring. The available energy is what's stored in the hammer spring. Replace the light hammer in a gun with a 5 lb DA pull with a stock hammer. Change nothing else. It won't go bang. Energy is the same, the spring hasn't changed, just the velocity of the hit on the primer has changed. 

[Carmoney]

4 hours ago, TheBrick said:

Carmoney, I never locktite a backed out strain screw. They are cheap enough to buy and cut to length when seated firmly in addition to blue locktite.

 

Bingo!  

[Spaceball]

On 24/08/2016 at 1:44 AM, Toolguy said:

You can bend the mainspring in the middle with a gradual curve, then use a longer strain screw or a #8-32 x 1/2" setscrew with blue loctite. Caromoney's mileage may vary, but I have never had a problem in many years. On mine, I do an S bend with gradual curves. The object of the game is to get the hammer stirrup as nearly horizontal as possible. It is normally going up at about a 45 degree angle. By putting bends in the spring, we are effectively shortening it's vertical height, which in turn brings the stirrup down with it. All this puts a lot less downward pressure on the rebound slide which allows us to have a lighter rebound spring that is still snappy in the return direction. It also allows us to have an even heavier hammer fall while at the same time, a lighter trigger pull.

Doing this, with my proprietary rebound spring and a couple of other tweaks makes it pretty easy to get a reliable 6 - 6.5 Lb. DA on any K,L or N frame. Every gun is different, so no 2 actions are exactly alike, but they can be very close to the same,

Hi Toolguy.

Could you share some photos of this? I noticed that my K frame stirrup is at 45 and the main spring would need LOTS of bending to get it sitting flat.

Thanks

[Toolguy]

I don't want to post any pictures right now, as I'm trying to come up with a spring kit. Putting anything in the public domain might affect the ability to patent it.

[Alaskan454]

45 minutes ago, Toolguy said:

I don't want to post any pictures right now, as I'm trying to come up with a spring kit. Putting anything in the public domain might affect the ability to patent it.

Under the new system disclosure still protects the inventor unless you wait longer than the grace period, either way it's good to be careful about what you put out there. 

Edited August 30, 2016 by Alaskan454

[Distant Thunder]

2 hours ago, Toolguy said:

I don't want to post any pictures right now, as I'm trying to come up with a spring kit. Putting anything in the public domain might affect the ability to patent it.

But, but Warren. You know we'd never tell ANYONE about this. It'd just be between you and us. We promise.

[Toolguy]

Well Bob - I know you and my other 2 friends wouldn't, but what if someone else were to find this forum.....?  

Edited August 30, 2016 by Toolguy

[kevinj308]

You gotta watch out for lurkers too! 

All in fun, definitely protect your intellectual property. There's a ton of amazing info in this thread alone, not too mention this whole website. So many years of experience and helpful people. Thanks too all!

 

[Alaskan454]

After reading this I realized I never weighed my hammer after chopping off the spur.  It ended up at 374 grains just by trimming it flush with frame.  I've been running it at 5.5 lbs with 2lb 12oz of that from the rebound spring and it's been 100% with federal primers.  I might see if I can get it closer to 350 grains and find out if that makes much of a difference.

[matteekay]

Oh yes, we lurkers abound! I actually just ordered an Apex for my 627 based on this thread.

 

What mainspring should I use? The stock S&W PC spring or the Wolff Type II that's in there right now.

 

Also, hi Toolguy! I want dem springs! Lol.

[Alaskan454]

Play with both and see what you like best.  I have grown accustomed to the feel of the Wolff reduced power but I know some gunsmiths modify parts to their liking.