Stovepiping -- could new hammer spring be to blame?

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garybok
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Stovepiping -- could new hammer spring be to blame?

Post by garybok »

I have a question for the more savvy P64 users on this board. I've had my P64 some months now, but only recently started having problems with stovepiping -- a spent shell that hangs up in the ejector port. It doesn't happen often, maybe once or twice per 50 round box. But, of course, once is too often if you're considering using the P64 for home defense or concealed carry.

I replaced a broken decocker lever a couple months ago (thanks to everyone for the pointers, by the way!). When I did that, I also replaced the factory hammer spring with a Wolff 19-pound spring. I didn't change the recoil spring, though, since the sharp recoil never really bothered me. But now I'm wondering if I should have gone to a stronger recoil spring to "offset" my weaker hammer spring. So my question to the more learned members here is this: Does that make sense? Is it possible that a weaker hammer spring, without being offset by a stronger recoil spring, could make the slide cycle "too fast"? My theory is that, without a stronger recoil spring to resist it, the blowback is causing the slide to slam back and forward too quickly, catching the empty shell before it fully clears the port. Is that plausible? Or am I just spouting nonsense, making up theories without fully understanding the blowback mechanism?

I'm shooting the same ammo I always did (Fiocchi), plus I bought a couple of boxes of RWS at the range and it still happened. I thought maybe I was starting to limpwrist for some reason, but no matter how I careful I am about maintaining a firm, straight grip, it still does it occasionally. Plus, when my son-in-law fired it, it stovepiped on him once as well. It's happened on each of three different magazines, as well. So I think I've eliminated all of the other possibilities. Or am I overlooking something?

My next step is to go back to the original hammer spring, but before I do that I thought I'd run it by you guys. Any other thoughts? Thanks again!

Gary
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Re: Stovepiping -- could new hammer spring be to blame?

Post by dfunk »

Plausible? Sure. Want to find out? Test it.
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Hurryin' Hoosier
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Re: Stovepiping -- could new hammer spring be to blame?

Post by Hurryin' Hoosier »

I must be missing something, here. How would the hammer spring cause stovepiping?
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garybok
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Re: Stovepiping -- could new hammer spring be to blame?

Post by garybok »

Hi Hoosier,

It sounds sort of "out there," I know, but here's my theory: If I understand the operation of a blowback pistol correctly, the slide is "blown back" by the force of the powder igniting. When it does, the slide pushes back against resistance from the recoil spring, but also against resistance from the hammer spring too. (Which is why it's always easier to rack the slide if the hammer's already cocked.)

According to the Wolff website, the factory recoil spring is rated at 18 pounds, and the factory hammer spring is rated at 24 pounds -- a combined total of 42 pounds of resistance. When I switched to a 19 pound hammer spring without changing the recoil spring, I reduced that total by 5 pounds. With less resistance, the slide cycles faster, occasionally catching the spent round before it clears the ejection port.

At least, that's my theory. From some of your other posts you seem to have a fair amount of experience with handguns, so if you tell me I'm all wet I'd probably be inclined to believe you. But it's stovepiped for two different shooters, using two different brands of decent ammo, and three different magazines, so I'm not sure what else it could be. I'd love to hear other suggestions. Meanwhile, as dfunk suggests, I plan on testing it this weekend, either by going back to the original factory hammer spring or by adding a stronger recoil spring to get the combined resistance back up to about 42 pounds.
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Re: Stovepiping -- could new hammer spring be to blame?

Post by Weasel640 »

There are some other things you would want to consider.

First if the resistance on the slide traveling rearward was to little then the power to push it back forward would be lesser as well. Thus it would stay open longer. Unless it's traveling fully rearward and bouncing off of the trigger guard. Have you checked the trigger guard for signs of unnecessary wear?

Usual causes for stove pipes are normally in the chamber, extractor, and ejector. Have you checked those areas for wear or excess carbon? On blow back pistols it is important to keep your chamber clean as carbon build up in the chamber can cause extraction problems. A good cleaning can sometimes fix these problems.

Another thing to check is your brass. Are there any miss shaped peaces that were shot? What about the primer is it a nice primer strike, or a drag mark?

I'm a little skeptical about your theory. There are lots of people on this forum and elsewhere whom have lowered the hammer spring less than 19 pounds and not touched the recoil spring with no problems.
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Re: Stovepiping -- could new hammer spring be to blame?

Post by LantanaTX »

I am using an 18# Wolf hammer spring and have shot it with both the stock and Heavier 22# Wolf recoil spring and have never experienced any type of feeding or ejection problem. As stated above, I would do a good cleaning focusing on the chamber, ejector and extractor. I would pay special attention to the extractor, maybe with the slide off push a round or empty brass in and see if the extractor has a good grip on it. Make sure the extractor isn't gummed up and moving freely against its spring.
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Re: Stovepiping -- could new hammer spring be to blame?

Post by Hurryin' Hoosier »

LantanaTX wrote:I am using an 18# Wolf hammer spring and have shot it with both the stock and Heavier 22# Wolf recoil spring and have never experienced any type of feeding or ejection problem. As stated above, I would do a good cleaning focusing on the chamber, ejector and extractor. I would pay special attention to the extractor, maybe with the slide off push a round or empty brass in and see if the extractor has a good grip on it. Make sure the extractor isn't gummed up and moving freely against its spring.
Same here. I guess the hammer spring could have something to do with it, but I don't think that it's likely.
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garybok
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Re: Stovepiping -- could new hammer spring be to blame?

Post by garybok »

Thanks for all the great advice, everyone. The more I read it, the more I'm beginning to doubt my theory. On the other hand, I still haven't found a likely alternative. I checked the extractor very carefully, and everything in the chamber and extractor area appears to be clean and operating smoothly. (I clean it religiously after every range session.) I removed the recoil spring and loaded a magazine with snap caps so I could operate the slide manually observe the operation in slow motion. Everything appears to operate exactly as designed, so I'm not sure what happens to make things go wrong "under pressure."

Weasel, I checked the trigger guard as you suggested and you can definitely see where the finish is worn off there, and on the corresponding place on the underside of the bottom "lip" at the front of the slide where it's hit the trigger guard. But I can't say how long it's been that way. While the finish is somewhat worn, there are no dings or dents or signs of obvious damage. The wear could be just the product of 38 years of operation.

I have a pack of recoil springs on the way from Wolff, so I can experiment with some different combinations of hammer and recoil springs. Of course, the tricky part is it doesn't stovepipe every time, just a couple of times out of every 50 to 100 rounds. So even if I do cure the problem, I won't be able to tell for sure right away.

So I guess I need to plan on making many trips to the range to be sure. Oh, well. I guess I just have no choice. Tough duty, but somebody has to do it, right?
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Re: Stovepiping -- could new hammer spring be to blame?

Post by snailman153624 »

It's gonna be your extractor, or you may have some galling in the headspace of the chamber that's not allowing the round to slide out as smoothly as it should. I would suggest cleaning out the chamber of the barrel very carefully, and also inspecting the breech face for damage (others on here have had problems with the breech lugs breaking off in the past..it's rare, but I've seen pictures).
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Re: Stovepiping -- could new hammer spring be to blame?

Post by garybok »

Thanks, snailman. Good advice. I've checked the extractor and breech face very carefully, and cleaned and cleaned some more, including the chamber. All looks okay. The only possible exception is a very, very small nick on the outside perimeter of the barrel, which I understand must have happened when someone let the slide slam forward on an empty chamber. It's extremely small -- I tried to take a picture but don't have good enough equipment. And it's on the very outside edge of the barrel -- you can see it if you look carefully through the ejector port when the slide is pulled back a little. Just a tiny little ding, that doesn't come close to the cartridge itself. I noticed that the first time I cleaned it, and it has never caused a problem before, but that might be a clue.

So I went back to all of the original factory springs and went back to the range today. I finished up a half-box of RWS and had one stovepipe out of about 20 rounds. Then I switched back to Fiocchi and shot another box and a half -- with no problems at all. I saved the round that stovepiped but couldn't see any unusual marks on it. There were two very, very small nicks around the rim, but you almost needed a magnifying glass to see them. Certainly nothing that I would call "damage," by any means -- just normal wear you'd expect from a round that had been ejected.

I paid particular attention when the stovepipe happened, and saw that the next round was almost fully chambered. It only stopped because the stovepiping round stopped the slide from going into battery. That makes me suspect the extractor is doing its job and removing the spent round from the chamber just fine.

So I'm not sure I'm any closer to a solution. It could be a combination of very small things, such as slight wear on the extractor, very slight damage around the outside edge of the barrel, a recoil spring that's just getting weak after 38 years, a brand of ammo that is just slightly less powerful (or maybe more powerful). No one of them is enough to cause a problem, but put them all together and I have an occasional stovepipe. At any rate, with Fiocchi ammo and factory springs, the problem seems to have gone away, so unless curiosity gets the better of me, I'll probably just leave it alone for a while and see what happens.

Thanks for all the good advice!
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Re: Stovepiping -- could new hammer spring be to blame?

Post by Hurryin' Hoosier »

Maybe a little intermittent limp-wristing, too? I know that I've caught myself doing that 2 or 3 times in 100 rounds with my 1911.
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Re: Stovepiping -- could new hammer spring be to blame?

Post by garybok »

Yep, that's always a possibility. Can't rule it out completely.
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Re: Stovepiping -- could new hammer spring be to blame?

Post by Weasel640 »

If there is wear on your trigger guard, I'd suggest replacing the recoil spring with a new one at factory specs or better. One of my P-64s came to me very worn and you could tell it had been used allot. However even with all that use the it's trigger guard is still clean, un-marked. If your slide is slamming into it, it's only a matter of time before you'll have to replace it or worse.
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garybok
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Re: Stovepiping -- could new hammer spring be to blame?

Post by garybok »

Thanks, weasel, good advice. I didn't realize the loss of finish on the front of the trigger guard was unusual. I thought everybody had it. New recoil springs have been shipped. When they get here I think I'll start experimenting again till I get the right combination of hammer spring and recoil spring that works best for mine.
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Re: Stovepiping -- could new hammer spring be to blame?

Post by Ketchman »

Garybok,

The "nicks" on the cartridge rim are most likely from the magazine lips. I found all mine had corners so sharp they would occasionally cut my fingers as well as dig groves into the casing rims. I took as little emery cloth to the lips and took the sharpe edge of my mags and have had no sliced fingers since. Not too much off though, just break the edge. Of course this won't help your stovepipe problem though.
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