Author Topic: Increasing double action hammer movement. (Read 1651 times)

corbanzo · « **on:** April 16, 2012, 11:15:36 PM »

In some guns such as the smith 686, taurus raging bull, ruger super redhawk there are problems with light primer sticks in double action mode.

My current is a taurus raging bull, that when I use CCI small magnum rifle primers (454 casull) in double action I get about a 15% FTF rate.

Now I have polished the whole inside so it is slick as snot, purchased a new mainspring, tried shimming the mainspring, and am soon to try some different higher poundage springs in it. Though better, so far I've still got the same problem.

Single action is fine, other primers are fine. I know CCI has hard cups and I should just stray from them... but I would like to know that my gun will fire all the time under any condition.

Next on the list is double action mode. Trying to machine a new DA hammer sear to keep engagement longer and increase hammer travel. Just wondering if any of you have tried this and with what results?

So far I am looking at left with these options:

DA sear for longer engagement
Higher power spring (though I don't want to make my trigger pull skyrocket)
Extended firing pin (If I can find one that fits, I ordereed an extended smith pin to see if i can fit it)

Any other ideas you guys can come up with while I'm brainstorming?

gunnut69 · « **Reply #1 on:** April 18, 2012, 05:46:51 PM »

You could try lightening the hammer to increase its velocity at impact which should give it more energy. The firing pin length has some limits as at higher pressures piercing a primer would be dicey! If the current pins protrusion is within limits I'd leave it be. Be sure to measure protrusion to be sure. Let us know how this comes out,,I'm intrugued!

corbanzo · « **Reply #2 on:** April 18, 2012, 09:55:57 PM »

Yeah, I've thought about that, but my problem being with harder CCI cups, piercing shouldn't be an issue.

And I don't think lightening the hammer is going to help... and increase in velocity and lessening the weight... especially being that inertia is mass x velocity. Lower mass=lower inertia.

Bigeasy · « **Reply #3 on:** April 18, 2012, 10:39:18 PM »

A couple thoughts come to mind. Is it possible there is enough front / rear play between the cylinder and crane that upon hammer strike, the cylinder is being pushed forward, cushioning the firing pin hit?

Is the load you are using fully seating? If the case mouth is just touching the edge of the chamber end, or the bullet is oversize, and rubbing in the chamber throat, it could be causing misfires as both conditions would again cushion the hammer blow.

I think you are going to run into problems trying to re-engineer the double action system. Unless you want to try it for the sake of just doing it, I would just eliminate what is obviously a problematic load in that weapon, and use a softer, reliable primer.

Larry

corbanzo · « **Reply #4 on:** April 18, 2012, 10:58:27 PM »

Yeah, everything else is tight. It only happens with CCI primers, and they seat fine, so I am certain the hammer strike is the cause.

I do load with other primers, I just don't like the thought of there being something in .454 my gun won't fire reliably. - .45 colts with CCI large pistol primers fire fine, its just the smaller, hard cup of CCI small rifle primers that gum it.

Any modifications I try are going to be with parts I machine myself, or aftermarket parts I buy so I can keep all the stock components around if they end up being the best choice.

gunnut69 · « **Reply #5 on:** April 19, 2012, 06:42:16 PM »

Energy is mass x velocity squared... The increased energy will dimple the primer a bit deeper.. Still the only reliable answer may be a stiffer hammer spring. Remember you are trying to use a rifle primer in a pistol. The rifle primers are harder to allow it to handle higher pressure levels. One should think the 454 would handle harder primers. Perhaps a call to Taurus customers service would be smart.. Surely they would have some answers..

corbanzo · « **Reply #6 on:** April 19, 2012, 11:53:59 PM »

I do like my taurus guns... but their customer service are a bunch of idiots...

Energy = mass x velocity^2 yes.

But we aren't interested in energy. We are interested in inertia... because inertia is the bodies resistance to being stopped, so that equation is inertia = MV

Though inertia is a form of energy, they have to be looked at in different ways....

Like if I have a 160 grain 7mm and a 225 grain .338 which I create the same energy in my load... the 7mm will slow faster, release more energy and not penetrate as far as the .338 because even though it has the same energy, the .338 has more inertia.

Luckyducker · « **Reply #7 on:** April 20, 2012, 01:13:37 AM »

I have a Ruger Bisley Vaquero chambered in 45LC that I had worked up a load using Starline 454Casull brass trimmed to 45 length, 335 grain gas check cast lead bullets and Mag Tech small rifle primers and it went bang every time until I swapped the bisley hammer for a standard Vaquero / Blackhawk hammer, then the misfires started and I have since quit shooting this load. I tried the same load with 45LC brass and the bullets would jump crimp under recoil so I abandoned it as well. A lighter hammer will not help your ignition problem. You may have to switch to a different brand of primer, one with a softer cup.

gunnut69 · « **Reply #8 on:** April 20, 2012, 07:54:43 PM »

Your aurgument is falacious.. In your comparasine the penetrating bodies change, in the case of your revolver the penetrating body stays essentially the same, the firing pin.. Speak to the customer service folks before proceeding but more hammer speed will increase energy and penetration of the firing pin..

corbanzo · « **Reply #9 on:** April 20, 2012, 10:53:40 PM »

Well if you would like it to be the same then it would be a 7mm 180 grain and a 7mm 160 grain, the 160 faster to achieve the same energy and the example still remains the same. - the diameter was just for detail.

Making something faster does not always increase inertia.

And in all reality, with a 14# spring on a comparatively small hammer in the first place, the gain from cutting even 5-10% off the hammer is going to be not much especially considering the small amount of room for acceleration. - Which brings me back to my goal which is increasing the distance with which the hammer can accelerate.

trotterlg · « **Reply #10 on:** April 22, 2012, 07:00:53 PM »

Quote

It only happens with CCI primers

Hard to resist stating the obvious, but just don't use them, they don't work and misfire all the time, but I still use them anyway?

. Do I miss something here? Larry

corbanzo · « **Reply #11 on:** April 22, 2012, 09:14:54 PM »

Yes you are missing something. You didn't read the whole statement.

"[size=78%]Single action is fine, other primers are fine. I know CCI has hard cups and I should just stray from them... but I would like to know that my gun will fire all the time under any condition. [/size][size=78%] [/size]"

From my original post.

Any condition including any components.

keith44 · « **Reply #12 on:** April 23, 2012, 06:58:10 AM »

just a thought, but how old is this gun?? If it's got some age on it, or is brand new, there could be something limiting the travel of the firing pin. Since the single action hammer swing is greater than the double action it would show up first in DA on the hard cupped primers. try soaking with a penetrating oil and flushing out the firing pin recess. (easier than removing the firing pin and re-installing it)

corbanzo · « **Reply #13 on:** April 23, 2012, 11:42:43 AM »

Yeah I've been nuts deep in the firing pin pocket. Made sanded it smooth so the pin movement was flawless, checked the spring so it wasn't inhibiting anything, and pushed the pin full back into position without giving too much resistance... It bottoms out nice and easy, and the projection is actually pretty decent. I'm still gonna give the extended pin a try when I get ahold of it.

Gun is only about 6-7 years. And I fully disassemble it and clean it on a regular basis so gunk inside isn't a problem.

I was actually thinking of putting a little bit of solder on the back side of the firing pin, to see if the pin bottoming out, instead of the transfer bar bottoming out made a difference. Not enough to make the transfer bar ineffective. But that's something I'd like to try and get ahold of an extra firing pin to try...

Kind of like the safety style on a model 83 when the hammer and bar hit the pin...less energy loss in that system.

Too bad that jackass shot himself and marred the image cause he didn't know what he was doing. I hate it when idiots mar the image of good guns and makers...

trotterlg · « **Reply #14 on:** April 23, 2012, 11:53:07 AM »

Those CCI (probably 450's) are made for a 65,000psi cartridge, I have no doubt they are hard to set off in a hand gun, I use them in a 17 Remington. Yes, the are very hard, probably not made for a revolver and why they don't work in one. If you must try to make the go off, I think your best bet would be to reduce the size of the fireing pin to about .065 or so like the high pressure rifles that use that primer generally have or change the shape of the end of the one you have. Larry

corbanzo · « **Reply #15 on:** April 25, 2012, 11:28:46 AM »

That's one I hadn't thought of, thanks!

trotterlg · « **Reply #16 on:** April 25, 2012, 07:31:16 PM »

However, if you look around you will find some other small rifle primers that are even harder than the CCI 450's, they are mostly for Military automatic weapons, but then they probably will not work in your revolver either, so you may have to up the anty if you want it to shoot anything you could load for it. I think there is simply no way you will ever make that gun reliable with any primer you could find out there, stick with what the primer is made for and life will be good. Larry

gunnut69 · « **Reply #17 on:** April 26, 2012, 04:45:40 AM »

I understand the use of rifle primers in the pistol because of the high pressures.. Still lengthening the hammer fall is to increase the impact velocity... One other caution, don't reduce the firing pin tip too much as a loose fit will allow the primer to flow between the pin and it's hole.

trotterlg · « **Reply #18 on:** April 26, 2012, 05:56:24 AM »

I think the best thing to do is to change the shape of the end of the pin to allow a little more dent in the hard primers. Keep the length the same but reduce the area of the tip so it will have a lot more pressure per fireing pin tip area. Larry

keith44 · « **Reply #19 on:** April 26, 2012, 06:25:24 AM »

Quote from: trotterlg on April 26, 2012, 05:56:24 AM

I think the best thing to do is to change the shape of the end of the pin to allow a little more dent in the hard primers. Keep the length the same but reduce the area of the tip so it will have a lot more pressure per fireing pin tip area. Larry

just don't make it a point, you don't want to be piercing the softer primers.

SHOOTALL · « **Reply #20 on:** April 26, 2012, 06:36:17 AM »

You may want to look at the transfer bar. I don't know Taurus revolvers well but with S&W and Ruger sometimes a transfer bar can be the cause of your problem . It might be worth a look if you can get a spec on the part and alingment . If it drags or is not perfect alingment it could cause less power to transfer to the fireing pin.

keith44 · « **Reply #21 on:** April 26, 2012, 07:37:20 PM »

Quote from: SHOOTALL on April 26, 2012, 06:36:17 AM

You may want to look at the transfer bar. I don't know Taurus revolvers well but with S&W and Ruger sometimes a transfer bar can be the cause of your problem . It might be worth a look if you can get a spec on the part and alingment . If it drags or is not perfect alingment it could cause less power to transfer to the fireing pin.

I would expect that to show in single action mode as well as DA mode since the bar moves with the trigger. Not impossible though...

corbanzo · « **Reply #22 on:** April 27, 2012, 06:07:17 AM »

Yeah it's flawless in single action. I've looked at the transfer bar, it's tight and sits straight flush on the frame.

SHOOTALL · « **Reply #23 on:** April 30, 2012, 02:18:17 AM »

can you mark the parts with something like a marking pin the work the action in SA re mark and work it in DA and see if they match. With SA the timming may not be the same as when the shooter pulls the hammer all the way back to the full cock notch.
If all guns stayed in time there would not be rings around the cyl. of most revolvers

corbanzo · « **Reply #24 on:** May 01, 2012, 08:20:33 AM »

Well a big thanks to larry for putting the firing pin idea in my head! Definitely one of the more simple fixes... and so far it works.
Took the firing pin out, threw it in my drill and went to town shaping it. Original shape chucked up.

First I tried a polishing stone, but of course, firing pin hard as hell, and it cut into the stone, ha.

So then I decided to go with a fine steel file, which worked wonderfully.

And the end result, slight taper on the end.

So to do my testing, took a bunch of primed empties. Pre modification - one cylinder, 1/5 misfired. Post modification - three cylinders, no misfires. I'm a big fan of 100% results. Threw in some 45 colt primed empties, and no problems there either. (Primers backed out a bit, but they didnt have load for pressure to hold them in, threw a couple loaded rounds down the barrel to double check and all was good)

Very simple and it worked. I'm happy. Time to quit screwin off and go shootin! I recommend you all do the same.
Thanks again Larry.

trotterlg · « **Reply #25 on:** May 01, 2012, 01:58:56 PM »

As long as you don't get primer flow back into the gap around the fireing pin life will be good. With those hard primers, I doubt then will even start flowing with those low pressures. Good luck. Larry

SHOOTALL · « **Reply #26 on:** May 02, 2012, 02:18:57 AM »

corbanzo , if you fire cases with out a load only primers why would they back out ? the flash hole is clear and no resistance is there to build pressure . If that happened to me I would question the primer - primer pocket fit . Over the years I have picked up primed brass at gun shows and not trusting the primer fired them rather than deprime live primers ( I have done this also with out a problem though) and have never had one back out . I have experinced some brands of primers that were a lose fit in some cases mostly after several reloadings.

keith44 · « **Reply #27 on:** May 02, 2012, 05:37:58 AM »

I've had primers push back from empty cases on several occasions. Since the flash hole is small there is a pressure build up in the primer pocket (all that black stuff all around the inside of the primer pocket that has to be scraped out has had pressure on it) The primer should move some small amount in the direction of being deprimed. Too much movement, or primers falling completely out is a sign of gun problems

corbanzo · « **Reply #28 on:** May 02, 2012, 06:35:26 AM »

Yeah I double checked to make sure with loaded rounds. It was when I used 45 colt brass, large pistol primers, so they have more primer pocket to push back against. Without a loaded round the only force in the gun is the primer pushing back. With a loaded round there is recoil pushing back, pressure from the round pushing back, and that offsets the force of the primer pushing back.

corbanzo · « **Reply #29 on:** May 05, 2012, 06:54:14 PM »

So I noticed one more thing to grind down. On the hammer there is a forward spur that controls pin protrusion. I ground it down a bit so it didn't hit the frame so much. You can see in the picture it hit on the bottom right part of the red.