FTF on first shot in full magazine

Mods and Fixes by P-64 users...
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gman68w
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FTF on first shot in full magazine

Post by gman68w »

My P64 came with two used factory mags, and lately both are failing to feed the second shot if they've both been loaded up to the full six rounds. But they feed and function just fine with five. I figure that since they're used mags, the springs are weakening. But it's weird that they'd both begin to fail at the same time.

Another thing is when I have to re-rack the second shot, I have to give the back of the slide a little love tap to bring it fully into battery. Do you think something else is gummed up inside? I've scrubbed out the chamber and feed ramp, oiled the rails, and done all the other usual things.
Jesus sez 'Pack Heat' Luke 22:36: "Then said he unto them, But now,
he that hath a purse, let him take it, and likewise his scrip: and he that
hath no sword, let him sell his garment, and buy one."
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chestertnted
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Re: FTF on first shot in full magazine

Post by chestertnted »

When you have to nudge the slide to return to battery, something is amiss. I would suspect fouling, but you have cleaned it well.
Could be need a Wolffe spring kit.
Keep us informed.
"For the Founders, the right of the citizen to be armed-they never imagined a world in which they would be disarmed for the supposed benefit of preventing access to weapons by madmen."
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gman68w
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Re: FTF on first shot in full magazine

Post by gman68w »

It's got a Wolff recoil spring in it already. That's the other thing, this issue hasn't come up until I started using Red Army Standard Elite ammo. It was advertised as having been made specifically for the P-64. I'd thought that it meant a P-64 with the original spring, like it had been given a reduced amount of powder to make recoil lighter on the softer spring. But as I said, once I get the second of six rounds in the chamber, it cycles the rest of them just fine. This happens on both the magazines I've got, so either the springs are failing on both at the same time (which would be a fantastic coincidence), or the ammo is off-spec for an XP recoil spring.

I can't find where I put the original spring, so I can't test that theory at the moment.
Jesus sez 'Pack Heat' Luke 22:36: "Then said he unto them, But now,
he that hath a purse, let him take it, and likewise his scrip: and he that
hath no sword, let him sell his garment, and buy one."
robhic
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Re: FTF on first shot in full magazine

Post by robhic »

Original recoil spring is 18#. I had one or two P64s that didn't return to battery every time. I put the 20# spring in and no problems since. I'm no expert on springs but just that extra 2# seems to keep my wayward P64s honest. Don't know if that'll help your FTFeed problems, too, but who knows? Good luck.
- Robert

"Giving Money and Power to Government is Like Giving Whiskey and Car Keys to Teenage Boys" - PJ O'Rourke
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Curly1
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Re: FTF on first shot in full magazine

Post by Curly1 »

If you have other brands of ammo try that and if the problem goes away then it's the new ammo.
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Re: FTF on first shot in full magazine

Post by gman68w »

I'll get ahold of some as soon as the bills are paid. But as I said, everything cycles fine if I only load the mags to five rounds instead of six. It would be bizarre if something about the ammo prevented feeding of the second of six rounds instead of five. Unless maybe it's the combination of a perfectly fine mag spring pressing up the second round too quickly into a slide that's retracted only -just- far enough to eject the first round, but without enough space to chamber the second. But is there really a large enough difference in spring tension between five and six rounds to cause this?
Jesus sez 'Pack Heat' Luke 22:36: "Then said he unto them, But now,
he that hath a purse, let him take it, and likewise his scrip: and he that
hath no sword, let him sell his garment, and buy one."
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Curly1
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Re: FTF on first shot in full magazine

Post by Curly1 »

I would also do a side by side visual inspection of the new ammo you get later if it works out to the Red Army rounds to see of there is any difference size wise.
Laugh Hard and Often.

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Re: FTF on first shot in full magazine

Post by snailman153624 »

Spring force depends on how compressed it is. 22# means when you compress it 1/2", you get 11 lbs of static force. 2" means 44lbs.

Friction also varies proportionally, but to the load. Put 10 lbs of force on a cartridge, and if mu is 0.2, you get 2 lbs of static friction to overcome.

What that means is as you put more rounds in the magazine, it gets harder to slide the top round out. The mag spring is more compressed, so it exerts more force on the stack. The recoil spring has to overcome this friction to load the next round.

Your recoil spring is either too stiff for the ammo and the slide isn't cycling back far enough to build enough momentum on the return stroke, or you have too much friction in the slide somewhere. Or, the ammo cases aren't slick enough to let the cartridge slide smoothly.
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chestertnted
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Re: FTF on first shot in full magazine

Post by chestertnted »

I use Brass ammo. Try a different load!
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Re: FTF on first shot in full magazine

Post by gman68w »

RAS Elite is brass.
Jesus sez 'Pack Heat' Luke 22:36: "Then said he unto them, But now,
he that hath a purse, let him take it, and likewise his scrip: and he that
hath no sword, let him sell his garment, and buy one."
robhic
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Re: FTF on first shot in full magazine

Post by robhic »

I tend to agree on the ammo suggestion. I haven't tried Red Army (got 1 box). But I had problems with a couple P64s that would shoot the "polyformance" polymer-coated ammo perfectly, yet choked on the "Silver Bear" nickel-plated ammo. You'd think finish wouldn't make a difference and if it did, the nickel-coated would probably be the better one, right? Nope. Still a mystery no one can explain. The P64 is built like a tank, is a really neat little fire-breathing firearm but a couple of mine have sensitive stomachs....
- Robert

"Giving Money and Power to Government is Like Giving Whiskey and Car Keys to Teenage Boys" - PJ O'Rourke
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gman68w
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Re: FTF on first shot in full magazine

Post by gman68w »

The brass cases have a lot of scorching and residue on them when I find them (still burying themselves into the 4x4 posts, remind me to post more photos of that later). Going on what little I know about ammo in general, I'm leaning more and more towards the "loaded with less powder" assumption. If there were a full charge, the brass would have expanded fully before ejection, and not have so much burn left on it, right?
Jesus sez 'Pack Heat' Luke 22:36: "Then said he unto them, But now,
he that hath a purse, let him take it, and likewise his scrip: and he that
hath no sword, let him sell his garment, and buy one."
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gman68w
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Re: FTF on first shot in full magazine

Post by gman68w »

Started loading the magazines with five rounds each, and the issue persists. After the first shot, the second fails to feed. I've got a couple photos here of one of these FTFs. You can see the bullet has a gouge along the center of the nose, makes it look like it was pressed together from two halves, and a dent just to the side of it. There's also a ding on the headstamp (right between the R and E, purty close to the primer, -that- was close!).
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Jesus sez 'Pack Heat' Luke 22:36: "Then said he unto them, But now,
he that hath a purse, let him take it, and likewise his scrip: and he that
hath no sword, let him sell his garment, and buy one."
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gman68w
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Re: FTF on first shot in full magazine

Post by gman68w »

Back again. Tried shooting a couple of mags of WPA and Brown Bear, and the same issue occurs. So it's not an ammo problem. Scrubbed and oiled the whole thing down again, and the very next mag didn't FTF on the first shot, but it happened again on the second. It occurred to me after looking at the photo of the bullet above, there might be a burr or something on the feed ramp. I'll have to borrow a dremel or something from someone and polish it down, see if that doesn't fix it.

I'm also gonna order a new-manufacture mag from Keepshooting.com, though I'm standing by my sentiment that it's just too weird that both magazine springs would start to fail at the same time.
Jesus sez 'Pack Heat' Luke 22:36: "Then said he unto them, But now,
he that hath a purse, let him take it, and likewise his scrip: and he that
hath no sword, let him sell his garment, and buy one."
snailman153624
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Re: FTF on first shot in full magazine

Post by snailman153624 »

Don't waste your money on the ks mags, unless you're just buying them for spare parts. The sheet metal is too soft or too thin, and it gets all bent out of shape from the recoil when fired. No I'm not joking.
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