I've been reading the reports of FTFire with .22 ammo. Most of the time I can eject a rim fire round that doesn't go "Bang", rotate it, and it will fire. Does anybody make a rim fire weapon that has a firing pin that strikes both sides of the rim? Is there a reason this idea won't work? It seems it would make rom fire ammo more reliable.
Double Strike Firing Pin For .22LR
- Thread starter Ky Larry
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bigfatdave
Member
I think it has been done with Olympic target pistols, but the reason it isn't common (by my understanding) is that the mainspring would have to be twice as stout (or more) to make two good divots in the rim, thus meaning that more force would be required to cock the hammer/striker, and probably not as much force as is available in a rimfire round or a revolver's comfortable DA trigger pull.
MachIVshooter
Member
It's been done before, and it's not a bad idea, but it's also not that practical.
For one, .22's aren't defensive guns, so reliability requirements are not as high.
Moreover, misfires just aren't that common with firearms in good working order. Yeah, it happens. And a lot more often than with centerfire stuff. But even with the cheap bulk pack stuff, they're pretty few and far between.
For one, .22's aren't defensive guns, so reliability requirements are not as high.
Moreover, misfires just aren't that common with firearms in good working order. Yeah, it happens. And a lot more often than with centerfire stuff. But even with the cheap bulk pack stuff, they're pretty few and far between.
scythefwd
Member
MachIVshooter - I have an anschutz that will misfire 5-10 times out of every box of cheap ammo (thunderbolts) but won't misfire ever with aguila ammo. The annie is in top working order, and it might need a new spring but to have it only happen with 1 brand of ammo is highly suspicious. Then again, it also refused to eject those rounds that it doesn't fire (every time) so I suspect it is out of spec ammo, and not the guns fault at all.
I was doing some testing with a .22 semi-auto rifle last year, I'd fire 500-600 rounds per day some days. Some brands and lot numbers of .22LR were pretty bad. I think the quality control has been slipping since everybody is producing ammo as fast as they can ship it.
bigfatdave
Member
It is all about the primer compound in the rims.
Pull the bullets and dump the powder on some of those duds, generally when I do so I find flakes of primer mixed into the powder and very little primer actually in the rims where it belongs.
A double firing pin face would multiply your chances of hitting priming compound by two, but better ammo and better ammo handling (not just after purchase, either) will do better than 2x.
Pull the bullets and dump the powder on some of those duds, generally when I do so I find flakes of primer mixed into the powder and very little primer actually in the rims where it belongs.
A double firing pin face would multiply your chances of hitting priming compound by two, but better ammo and better ammo handling (not just after purchase, either) will do better than 2x.
SMMAssociates
Member
KY Larry:
One thing you can do, if you're technically able to, is to clean the firing pin tube/channel, maybe increase the strength of the mainspring, and sharpen the pin itself a little....
In my case, a new Kimber .22LR conversion kit (on top of an old Colt frame) wasn't too reliable. It depends on the original mainspring, and it was a little light.
.22 firing pins tend to have a rectangular or square footprint, like a chisel, but this thing uses a round one similar to the basic 1911. No idea why Kimber did that.... Anyway, I sharpened the pin a little.... This made the cross section a little bit smaller, but increased the force at the point of impact on the case. Worked pretty well....
That said, I've seen a lot of misfires of late in what might be called "budget" ammunition. One of my regular shooting buddies has an S&W M41 that tends to misfire constantly.... We put his failures into my Kimber kit and they won't fire in that either.... Admittedly, the stuff is kinda poor, but while I'd expect all kinds of variations in velocity, etc., failing to ignite seems a little unnecessary....
Just FWIW, if you're considering that Kimber kit, slather Gunslick or all kinds of lubricant (I like Gun Butter for this) all over the mating surfaces. Otherwise, you have to use the high-priced alternative ammunition selections, or keep the thing scrupulously clean. Gun Butter seems to let me run cheap stuff (CMS) and clean it when I feel like it.... (Failures to extract get common when it needs cleaning. Meantime, the magazines can get coated with wax at the ball end, and need cleaning.)
Regards,
One thing you can do, if you're technically able to, is to clean the firing pin tube/channel, maybe increase the strength of the mainspring, and sharpen the pin itself a little....
In my case, a new Kimber .22LR conversion kit (on top of an old Colt frame) wasn't too reliable. It depends on the original mainspring, and it was a little light.
.22 firing pins tend to have a rectangular or square footprint, like a chisel, but this thing uses a round one similar to the basic 1911. No idea why Kimber did that.... Anyway, I sharpened the pin a little.... This made the cross section a little bit smaller, but increased the force at the point of impact on the case. Worked pretty well....
That said, I've seen a lot of misfires of late in what might be called "budget" ammunition. One of my regular shooting buddies has an S&W M41 that tends to misfire constantly.... We put his failures into my Kimber kit and they won't fire in that either.... Admittedly, the stuff is kinda poor, but while I'd expect all kinds of variations in velocity, etc., failing to ignite seems a little unnecessary....
Just FWIW, if you're considering that Kimber kit, slather Gunslick or all kinds of lubricant (I like Gun Butter for this) all over the mating surfaces. Otherwise, you have to use the high-priced alternative ammunition selections, or keep the thing scrupulously clean. Gun Butter seems to let me run cheap stuff (CMS) and clean it when I feel like it.... (Failures to extract get common when it needs cleaning. Meantime, the magazines can get coated with wax at the ball end, and need cleaning.)
Regards,
AStone
Member
This is a very interesting thread
given the hassles I've experienced
in the last couple of years with FTFire.
given the hassles I've experienced
in the last couple of years with FTFire.
Dionysusigma
Member
Heck, why don't they just deform the entire rim? 
scythefwd
Member
because you still have to extract it.
The Bushmaster
Member
Buy QUALITY ammunition and stop buying bulk .22 and your problem will disappear...
Well, the difference in purely probabilistic terms is really 1 - (1 - x)² rather than 2x.
For example, if your chance of having a successful ignition with a regular firing pin is 0.9 (90%), then rather than it becoming 1.8 (180%) with a double firing pin, it actually becomes a realistic 0.99 (99%). Of course, this still oversimplifies the reality of the matter, but it at least gives one some idea of the difference.Heck, why don't they just deform the entire rim?
It would take a lot more force to adequately deform the entire rim, which would make for a heavier hammer/trigger pull. Instead, ammunition manufacturers should coat the entire rim like they're supposed to anyway.
SMMAssociates
Member
Some years back I was discussing a problem with one of my guns with a counterguy at my favorite gun pusher's.... The owner popped out from behind the wall and suggested that buying good ammunition would fix it.The Bushmaster said:
My response was: "As soon as you start selling it, we'll talk...."
Once in a while I win
....Regards,
bonza
Member
As did the original Henry & Winchester M.1866 lever action rifles to fire the .44 Henry RF rounds.
bigfatdave
Member
You are absolutely correct, Manco ... I oversimplified because I was focused on the likelihood of primer being under the firing pin's impact point(s).
Now here's a concept, why not add a few degrees of mechanical complexity and have the firing pin hit a different spot every time the hammer drops, giving an effective second strike capacity unlike just hitting the same (non-primed) spot on the rim?
Or we could just remove and rotate the rounds ... but I want it to happen automatically!
NavyLCDR
member
Another aspect of having a double impact firing pin - what would that do for accuracy? Does the firing pin hitting the rim on only side affect accuracy? Would it be better to balance the force of impact on two points 180 degrees from each other.
The Lone Haranguer
Member
The Freedom Arms .22 revolver has a dual-sided firing pin.
scythefwd
Member
paul - that anschutz is about as far from semi auto as it gets .... It's a model 54 action with a single shot sled permanently installed.
Equestrian
Member
seems like in a semi auto the additional force could simply be had with a softer recoil spring
fireman 9731
Member
That is in fact the root of the problem...
Interesting idea though...
SMMAssociates
Member
What might be simple, although I'd bet there would be accuracy issues, is to fit the "hammer" with a rotating firing pin, like that used to selectively fire two or more chambers in a derringer or pepperbox. Each shot would be with a different pin location.... Other than "don't let it work near the extractor", it shouldn't have any effect on extraction. A second strike would land someplace else....
The downside is that the location of the initial detonation may affect accuracy somehow. Probably irrelevant for most users, but the guys who like to cloverleaf at 200 yards will probably flame me....
Regards,
The downside is that the location of the initial detonation may affect accuracy somehow. Probably irrelevant for most users, but the guys who like to cloverleaf at 200 yards will probably flame me....
Regards,
AStone
Member
200 yds?! What the ... are you crazy?
We regularly create one ragged hole at 350.
How dare you spread the rumor that we're only good to 200.
___________
<awakes from dream>
Oh, wait ... never mind.
jnyork
Member
I myself have fired several one-hole groups at 200 yards with a .22 rimfire. Second shot usually screws it up.
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