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Carmoney

Revolversmith Mythbusters!

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Episode 1

Question: Will reducing the tension on the rebound spring of a S&W revolver, by cutting down the factory spring or replacing it with an aftermarket spring, cause the old problem of hammer push-off?

Answer: Nope. Push-off has nothing to do with the springs.

Analysis: Hammer push-off is the well-known condition in which the hammer on a cocked revolver can be released by pushing it forward with moderate thumb pressure without touching the trigger. You see it occasionally on older revolvers that have seen a lot of single-action use, and much more commonly on guns that have been modified by "kitchen table hackers" who blundered their stones into the single-action cocking engagement surfaces on the trigger and hammer. It is a dangerous condition that warrants immediate repair if the single-action cocking capability is to be retained.

We have been told several times recently, from an undoubtedly well-intentioned source, that reducing the tension on the rebound spring can cause push-off. This is not true.

In order to bust this myth, I took the sideplate off one of my 625s and removed the rebound slide and spring completely. (Note this is a nearly-new 625-6 that I recently customized for USPSA competition, but the single-action cocking capability on this gun remains exactly as it left the factory.) Then I carefully pulled back the hammer until the trigger bevel engaged the hammer's cocking notch. At this point, even with the rebound spring/slide assembly completely gone, the hammer was solidly engaged and would not release even with heavy thumb pressure applied to the back of the hammer. In order to depict this, I had my wife photograph me holding the gun while pulling forward on the hammer with my RCBS trigger pull gauge. You can see in the pictures that the gauge is completely pegged. What you can't see is that I am actually pulling very hard on the gauge, so hard it was causing my hands to shake enough we had to take several photos until we got a couple clear ones. You can get an idea how hard I'm pulling if you notice the blood has drained from my fingertips on the left hand holding the gun! The engagement remained solid, and the hammer never came close to pushing off. This experiment can be easily replicated on your own gun, if you would like to see it for yourself.

Bottom Line: On a revolver with proper engagement between the trigger bevel and cocking notch, the hammer will not push off--even with the rebound spring tension reduced clear down to zero. Myth busted!!

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Episode 1

Push-off has nothing to do with the springs.

Myth busted!!

Right on Mike. With a spring combination that gives my 625-8 a 5lb DA pull, I get a reliable 1 3/4lb SA pull with no Push-off. I don't remove or alter the SA notch or sear, the SA pull is just a by product. My others S&W revos are similar. Good notch and sear, no push-off.

I shoot club level bullseye occaisionally with my 625 and the SA gets used for the slow fire stage. Technically too light a pull to be legal, just for fun.

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Episode 1

....... Myth busted!!

Well done, Sir :cheers:

dj

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You can "COCK" the hammer with your thumb on a S&W Revolver? Who'd a 'thunk it? :surprise:

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It is kinda like hammer follow on a 1911, you can often cover up the problem for a bit with more spring pressure but it doesn't fix the problem....

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you have a wife? :surprise:

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Don't rub it in, David.

20 years in March.

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Very interesting test Mike, thanks for taking the time to write it up.

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Most revos that will "push off" in SA mode are victims of fools who tried to lighten the SA trigger pull by grinding on the SA sear. Once the hard surface is removed, the sear face wears and leads to insufficient engagement which allows push off to occur.

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It is kinda like hammer follow on a 1911, you can often cover up the problem for a bit with more spring pressure but it doesn't fix the problem....
And, like hammer follow, it usually means somebody buggered a trigger job at some point in the gun's history.

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Mike,

Your wife must think you are insane! :rolleyes:

Congrats, :cheers: my wife will have put up with me for 20 years this coming september!

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WOW :surprise:

All this just to prove to yourself that with that one gun you were right !

Not a very scientific test there mikey, using only one test group, but hey, you got the results you wanted !

Now I'm beginning to understand why we lose contributors to this forum.

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WOW :surprise:

All this just to prove to yourself that with that one gun you were right !

Not a very scientific test there mikey, using only one test group, but hey, you got the results you wanted !

Now I'm beginning to understand why we lose contributors to this forum.

Well, I think I only own about a dozen SW wheelguns (unless they have procreating again) but the innards on mine all work the same.

And his conclusion is pretty accurate IMHO. As long as the rebound spring applies enough pressure on the trigger strut to hold the trigger in place, the hammer should hold and not drop off the SA shelf on the sear.

But, that's just my opinion.

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As I indicated very clearly above, anyone who doubts the conclusion can replicate this test for himself.

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Your wife must think you are insane! :rolleyes:

Think?? ;)

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As I indicated very clearly above, anyone who doubts the conclusion can replicate this test for himself.

Wow Mike,

I can't believe the hostility coming out of New England. I would think after the free revolver clinic you put on for them at the Area 7, they would have nothing but reverence for your skill, knowledge, and good looks.

ps. What load are you using in the test gun ... Major???

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Wow Mike,

I can't believe the hostility coming out of New England. I would think after the free revolver clinic you put on for them at the Area 7, they would have nothing but reverence for your skill, knowledge, and good looks.

Talkin' smack early this year I see Mr. Walsh

And it's not hostility, more disappointment, that an individual can't accept what another has

observed thru his life time (so far) of working on older, probably not as well cared for revolvers,

and has to create this belittling little test complete with a condescending post.

oh well, back to real life.

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CAN'T WE ALL JUST GET ALONG :rolleyes:

Edited by ffl

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:lol: Edited by Carmoney

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And it's not hostility, more disappointment, that an individual can't accept what another has

observed thru his life time (so far) of working on older, probably not as well cared for revolvers,

and has to create this belittling little test complete with a condescending post.

Do you prefer perpetuating the misconception that the rebound spring controls push-off when it's the mechanical condition of the surfaces involved that create the problem? Unfortunately there are plenty of "keyboard parrots" that keep repeating things like this as gospel. I leave you with the still repeated "wisdom" that removing the hammer spur or lightening the hammer causes failure to fire. Do we need more BS repeated?

Edited by Tom E

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It is kinda like hammer follow on a 1911, you can often cover up the problem for a bit with more spring pressure but it doesn't fix the problem....

+100

Having hammer hooks with incorrect geometry causes the potential for "push off". Adding spring pressure to the engagement can increase the amount of pressure necessary to "push-off", but does not change the fact that the incorrect geometry still exists.

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It is kinda like hammer follow on a 1911, you can often cover up the problem for a bit with more spring pressure but it doesn't fix the problem....

+100

Having hammer hooks with incorrect geometry causes the potential for "push off". Adding spring pressure to the engagement can increase the amount of pressure necessary to "push-off", but does not change the fact that the incorrect geometry still exists.

Exactly ! ! all of our guns are machined differently, I'm not doubting for a minute that mikey's

results are not accurate, nor am I doubting RGS' claims about older guns he's worked on push

off with a lite rebound spring. (so how is the quality on some of your older Bangor/Punta (sp) Smiths ?)

and for TomE,

not trying to perpetuate any misconception, here we have 2 guys saying the same thing,

proper engagement surfaces lead to proper operating guns, change any of those factors

and you could have an issue.

Can you fix push off with a heavier rebound spring......depending on how bad the surfaces are, yes.

if you have a gun with proper engagement surfaces, will a lite rebound spring matter, looks like no.

will we all ever "just get along" unfortunately I doubt it (sorry ffl)

later folks,

10mm "just another keyboard parrot" Dave

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Your almost there.

Can you fix push off with a heavier rebound spring......depending on how bad the surfaces are, yes.

No you can't. All you can do is cover it up. The problem will still exist.

Here is another real world example.

If we take away your keyboard, you will still be an a$$, we just will not know it......

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All righty then. There's enough of that.

CLOSED.

-ld

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