Striker Spring

[500KV]

I think the light strikes is more likely either inadequate striker protrusion, or drag on the striker as it moves through the hole in the breech face,

I agree that this could contribute;

But could you enlighten me a little about this statement?

And by the way, a spring with the same wire diameter and material and four more coils (more turns) will be WEAKER and not STRONGER.

ETA: I think I see what you're saying now.
The assumption is that the spring is being totally compressed; right?

[mr.72]

But could you enlighten me a little about this statement? <snip>
ETA: I think I see what you're saying now.
The assumption is that the spring is being totally compressed; right?

No.

The physics of a spring dictates that with all other things being equal, the more turns, the lighter the spring. And this is also why cutting coils off of the spring will not really reduce the trigger pull, in fact it will stiffen the trigger pull, unless you cut it so short that there is no preload on the spring (in other words, the striker is not partially cocked by cycling the slide).

To make a lighter spring would require a spring with either more coils of wire, thinner wire, or wire made of a different material or alloy. In any event, a lighter spring requires a replacement spring. There is no way to modify the factory spring to make it weaker unless you work harden it or deform it mechanically or do something else to it to degrade the material the spring is made from.

Now getting away from the discussion about this striker spring in particular, but talking about springs in general, some people may find that shortening a spring by cutting coils can appear to reduce the effort required to begin to compress the spring, but this is only the case if the spring is under preload and after it is cut it is no longer preloaded.

So for example, let's say that I have a spring that is 10 lbf/in rate that is 1.0" in free length, but it is .75" in the installed length. So it is under 2.5 lb of pre-load. It will require 2.5 lb of force to just begin to compress the spring. So to compress it another .25" will require 5.0 lb of force total (2.5 preload plus 2.5 lb for the additional .25"). Now, if I cut 25% of the coils off of the spring so that now it is only .75" long, it will now be 13.3 lb/in (33% stiffer) but under no preload when installed. So to compress it .25" will require only 3.3 or so lb of force.

Now, with a Kahr striker spring, you would have to cut it down to the point at which it was not under a significant preload while the pistol was in the partially-cocked "ready" state in order to reduce the trigger pull. Maybe there is a sweet spot where you could cut the spring and result in a lighter trigger without compromising the function of the striker. The Kahr striker spring is under heavy pre-load when the pistol is partially-cocked. The more reliable way to reduce the trigger pull is as Jocko suggested, put a lighter striker spring in there and then hope for the best with respect to primer ignition. Jocko has good results. I am not so confident of lighter striker springs being a good idea universally.

Incidentally any of you S&W Sigma owners out there, the striker spring is the real way to lower the trigger weight. You can probably more safely reduce the striker spring in a Sigma than you can in a Kahr because the Sigma seems to have much more striker protrusion than a Kahr (at least .010" more) so it's not on the edge of not working to begin with.

[jocko]

If wolffs had not made this 5# striker spring for the kahrs, I certainly would not be experimenting either. Not sure a 5# striker spring is really to light either. It sure works great in my K9 and PM9 but Mr72, u described this spring thing very well. In as much as wolffs makes all of kahrs springs for their guns, I trust their 5# spring....

[500KV]

No.

The physics of a spring dictates that with all other things being equal, the more turns, the lighter the spring. And this is also why cutting coils off of the spring will not really reduce the trigger pull, in fact it will stiffen the trigger pull, unless you cut it so short that there is no preload on the spring (in other words, the striker is not partially cocked by cycling the slide)....

Very good read.
Thank you sir.

[mr.72]

I am sure Wolff probably delivers the 5 lb spring along with a stern warning that it is for "competition" or "range" use only. That is the case for the lighter striker springs for a S&W Sigma. I would take that warning very seriously with a Kahr, given their tendency towards light strikes even with the factory spring. A lighter spring is not going to make them any more reliable.

[jocko]

or mayle less reliable. More like a legal liability statement + a warning also. I really have not read alot about kahr light strikes with the factory springs, other than a very dirty striker chamber causing most all light strikes. I would think kahr 7.5# + striker spring would be more than sufficient for good primer hits.. I'm still looking for my first light primer strike out of both of my kahr with the 5# wolffs spring in it. No doubt it can happen but it can happen with 7# springs which most striker fired guns have. Other variables might come into play also. Possably a hard primer, or a primer that was not fully seated. Faulty firing pin and yes bad striker spinrg..

[mr.72]

Well you can read in detail the account of my gun going back to Kahr TWICE for light primer strikes and many, many other people with stock Kahr pistols with 7.5 lb striker springs and light strikes. It would be a mistake to assume that it is a dirty striker channel. I assure you mine was perfectly clean.

I think it's far more likely that the Kahr strikers either have inadequate firing pin protrusion, chamber headspace problems, out-of-spec strikers or breech milling resulting in drag or off-center running of the striker, etc. So either the striker does not protrude far enough to ignite the primers reliably (firing pin protrusion or chamber headspace), or drag on the striker causes the striker to slow down or fail to completely deploy and ignite the primer (dirty, out of spec striker channel, breech milling, striker). Or perhaps simply a defective striker spring is to blame for most of the light-strikes (who knows? Kahr, are you listening? This is a problem you need to solve).

But in whatever case, it is an absolute 100% guarantee that a lighter striker spring will not make your gun any more reliable. And if you are fortunate enough to have the planets in alignment and have a Kahr pistol that ignites all primers reliably 100% of the time then there is also a chance that a lighter spring will not reduce the reliability, but it will be subject to test.

Considering the high instance of FTF due to inadequate primer impacts with Kahr pistols in general, I would think that a lighter striker spring will be risky at best and require extensive testing in your own specific pistol before you can assume it is reliable.

[shootinbil]

Yes I bought the P45 used. The gun work fine with factory ammo and my reloads with Federal primers. It when I use Winchester primers is when I have the light strike .

[mr.72]

I have found that Winchester primers seem to be harder to ignite, but this is an indicator of a problem with the gun, and not a problem with the primers. In my case, originally the gun would fire Federal ammo just fine and have occasional problems with Winchester, but eventually it got to where it would not fire any ammo either Federal or Winchester more than about 40% of the time. So light strikes with Winchester primers may be an indicator of a problem that may suddenly become more serious and just because it currently reliably fires Federal primers does not mean it will always continue to function correctly.

[jocko]

only thing CERTAN in life is death.