Striker Spring

[shootinbil]

I am looking for a stronger Striker spring for a P45. When I use Winchester Primers sometime the striker just don't hit the primer hard enough. I call Wolff Spring and don't make a stronger striker spring for the Kahr.

[500KV]

I am looking for a stronger Striker spring for a P45. When I use Winchester Primers sometime the striker just don't hit the primer hard enough. I call Wolff Spring and don't make a stronger striker spring for the Kahr.

Initially, I had some light primer strikes with my CW-45 and Kahr sent me a new striker and spring.
This cured the problem BTW.
The new spring is stronger, by about 4 coils.
It didn't noticeably affect trigger pull, however I think that if I had just shot the gun more the problem would have cured itself.
Mine get better the more I shoot them.
You might give them a call.

[shootinbil]

Thanks for your help. I will call them on Monday.

[jocko]

Thanks for your help. I will call them on Monday.

only makes a lighter 5# striker spring. If u having issues with the factory spring and it has never been altered, indeed call kahr and get another striker spring. I use the 5# striker spring in my PM9 and have never had one light strike ever and that is about 2.5# lighter than factory kahr spring. I love the way it smooths out my trigger pull even.

I am assuming your kahr is new and not used etc, If used, u never know what anyone has done in the striker channel area either. You stated light strikes but never stated if the light strikes are causing failure to fire or that you just look at the primer indent and are making your decision that they are light strikes. there is a difference.

If u have never had that striker channel apart, indeed you could have a crud build up inside that channel causing light looking strikes. Normally kahr factory springs never wear out either, so I would advise for sure to clean that channel out perfectly and do not oil that striker channel either. Leave dry and clean.

Get a new striker spring from kahr while your at it and if u don't mind spending the extra bucks buy a new striker while you are at it. cheap insurance..If anyone should get light strikes my 5# system should produce them and I have never had a failure to go bang, but I keep that channel spotless to by using that small clean out hole in the bottom of the slide and just inserting a spray nozzle in there and sprayaing away. u will see fluids and crap coming out both end. walla, u have not cleaned the striker channel..

[mr.72]

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, and not the spring.

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. However, if the spring is too short it can cause a problem especially if there is drag in the striker.

My Kahr had light strikes and eventually they replaced the whole slide. I think these Kahr pistols have a design defect or two and one of these days Kahr is going to have to address it in an expensive manner. For the time being they seem to be content to band-aid it on a case-by-case basis.

[jocko]

Initially, I had some light primer strikes with my CW-45 and Kahr sent me a new striker and spring.
This cured the problem BTW.
The new spring is stronger, by about 4 coils.
It didn't noticeably affect trigger pull, however I think that if I had just shot the gun more the problem would have cured itself.
Mine get better the more I shoot them.
You might give them a call.

found out what I had originally thought was true. ALL KARH STRIKER SPRINGS ARE THE SAME, except the little P380. Howurs got 4 coils less and if it was a new gun, is beyond me, course another thing could have happened to is that the striker spring might have broken an when you took it apart to check things out that little part of the 4 coils might have droppd somewhere out of sight,but all kahr striker springs are the same..

If it was by chance a used gun, then the previous owner had just cut 4 coils off the striker spring to lighten trigger pull.

[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.

[ltxi]

Other folk have had light strike issues with WWB also. Personally, after studying this a bit, I've seen inconsistent/random light primer indentations in fired brass in two lots of current production WWB. Happens both in my Kahrs..K9/MK9/PM9..and my S&W 940 revolver. The only failures to fire have been in two of the Kahrs, the K9 and the MK9. Only once or twice in the K9 early in its life. Maybe half a dozen times in my MK9 over 500+ rounds before it went back to Kahr for repair for an unrelated issue and none since. I've never had a problem or seen this with premium Federal, the only other brand I've really checked; intentionally because it's my carry brand....consistent, adequate indentation.

Kahr striker protrusion is unquestionably on the short side. Couldn't figure out why they did that at first but think I understand now. Couple that with hard primers in high volume production ammo and you can have a problem.

I agree, btw, that this is more of a Kahr gun related issue than an indictment of Winchester's ammo as no other firearms manufacturer's product seems to have any problem lighting off WWB.

[mr.72]

I agree, btw, that this is more of a Kahr gun related issue than an indictment of Winchester's ammo as no other firearms manufacturer's product seems to have any problem lighting off WWB.

I think WWB is probably the most prevalent practice ammo in use by consumers.

But I expect Jocko to pop in and remind everyone once again that since he's had such good luck with his Kahrs, that means that there really is no design problem with them. :D

[jocko]

I think WWB is probably the most prevalent practice ammo in use by consumers.

But I expect Jocko to pop in and remind everyone once again that since he's had such good luck with his Kahrs, that means that there really is no design problem with them. :D

Not me Mr72. ur the man, u have all the answers. Not sure why u even own a kahr with all the issues and unrealibility they give. :59:

[mr.72]

I like my Kahr, quite a bit. I'd buy another one without hesitation. But I do wish they would solve their problems... mag drops, light strikes, plague a lot of Kahr P and CW owners.

If Glock comes out with a single-stack compact 9mm in the same size class as a P9 with typical Glock reliability then Kahr is going to really wish they had taken these complaints more seriously.

[ltxi]

If Glock comes out with a single-stack compact 9mm in the same size class as a P9 with typical Glock reliability then Kahr is going to really wish they had taken these complaints more seriously.

For sure.....I think Justin Moon is a genius and I wouldn't give up my PM9 for anything, but a single stack variant of a G26 or G27 at normal Glock pricing would fix Kahr's supply/demand problem in half a heartbeat

[Mudinyeri]

Reviving an old thread ... anyone install the 5# striker spring themselves? Anyone do a writeup or video?

TIA

[Mudinyeri]

Found a video on YouTube of how to disassemble the slide: YouTube - Kahr P9 Full Slide Disassembly & Reassembly (http://www.youtube.com/watch?v=Y5h5iexfLzg)

Pretty simple to replace the spring once you have the slide back removed.

If the trigger on my CW40 was like butter before, it's like melted butter now!

[mr surveyor]

Mr72 has written several "internet esays" on spring physics/dynamics. I think it would be great if he assembled his knowledge, as it pertains to firearms springs, and submit them in the form of a "white paper" that could be "stickied" here at Kahr talk. I seem to remember from somewhere (maybe another forum?) that Mr72 has had some professional hands on knowledge of spring technology.

It's great to have a true knowledge base at hand.

surv:)