Recoil Springs - pic info .....

[cordy]

I have shot/racked my Pup about 100 - 150 times and from the get go I have a FTF almost every other time I shoot so I from the start I tried several (4) types of different ammo to see if that was the problem. Two of the ammo changes were very good critical Defense Ammo (Hornady & Winchester) & still 50% FTF.  Could I be having a spring problem that would cause 50% failures? The cartridges that don't fire look like they are not hit hard enough compared to the ones that go off. My spring has lost about 1/8" of it's length in the 2 weeks I have owned it & the 100-150 shots/racks. What do you think?
 
Jim

[kjtrains]

It probably is time for a spring change.  The Critical Defense ammo is also a problem, because may be the batch with hard primers.  As to the Winchester, don't know why that would be a problem.

I would change the spring, use Winchester Silvertips, or Gold Dots, both 115 gr. or 124 gr. and go from there.

[Richard S]

What KJ said. And a good clean and lube, with some special attention to the firing pin area. Some "break-in dreck" may have worked its way in there.

Good luck.

[tracker]

To be more specific, do not use Critical Defense ammo; in addition to to what Richard said the only other variable is the hammer spring but not likely on a newer gun. The recoil spring is probably not the reason for the FTF.

[kjtrains]

Maybe not, but with 100 to 150 rds fired or racked slide and with 1/8"  loss in spring length, I would change the spring.  My thoughts.

[tracker]

Won't hurt; might help. I just changed one out that was 1/4" to 1/2" shorter after 150 rounds or so and everything had functioned flawlessly.

[leeyn]

I guess the Bros Rohrbaugh do not rate this spring with the same importance they do the mainspring. ...

[backupr9]

Interesting thread to a newby to the forum.  I have put perhaps 350 rounds thru my pup and am on my 4th recoil spring.  Each time I have cleaned the weapon I have noticed significant shortening of the spring compared to new ones.

An early gun magazine article recommended changing at "500 rounds!"  The factory recommends 200, but some references prefer 100.  My experience suggests for a carry/backup, having an completely clean/lubed pup with fresh spring is the only way to be safe and sure.  I will continue to change when obviously shortened or at about 100 rnds.

Advice re:  proper orientation of the spring on reassembly greatly appreciated...I was unaware of this, and it may have been the reason for feeding problems I had last spring.

[yankee2500]

The orientation of the spring is only on the OLD style springs, if your springs were purchased in the last few years from the factory it's not a concern.

[backupr9]

Thanks Yankee.  I couldn't see any difference in the springs that I just ordered from one end to the other.  

[Relic]

Springs are a funny thing.  Here is a picture of a new spring and one with 340 rounds of use:



As you can see, there is roughly 3/16" of set. (I didn't bother with the micrometer as the difference is obvious)  However spring rate isn't much different.  The used spring is approx 11% softer (takes ~11% less weight to deflect the same distance) than the new one.

The used spring has had one failure, a failure to feed/nose dive into the feed ramp, a called "limp wrist" by a new shooter.

Unfortunately I only have these two springs to test, so these results are not useable as a benchmark to determine spring wear rates.  That would take a quite a few more springs.

My homemade tester uses a fulcrum on one side so it has an arc and is not a perfect in-line press.  When comparing different lengths it requires me to place washers under the shorter spring to measure at the same place on the arc of my press.  It's fine for comparisons, but it's not accurate for absolute rate measurements.

[abboberg]

I know this is an old thread, but I wanted to add some information here since there seems to be some speculation.  I reverse-engineered the R9S spring guide rod assembly to learn that the larger spring is about 3-4 coils short of having a long life (there is just no space for those extra coils).  As far as the argument about which spring is working harder (we know it is the larger diameter spring based on experience), it is plain to see that the larger diameter spring is working harder since it has fewer working coils.  It is highly possible to use a Kel-Tec PF9 spring assembly (two counter-wound concentric springs) with the properly built rod ends, and never have a slide spring wear out in an R9 pistol.

[Faawrenchbndr]

I'm not an engineer,.......I'll use the recommended springs.

[BlueC2]

I know this is an old thread, but I wanted to add some information here since there seems to be some speculation.  I reverse-engineered the R9S spring guide rod assembly to learn that the larger spring is about 3-4 coils short of having a long life (there is just no space for those extra coils).  As far as the argument about which spring is working harder (we know it is the larger diameter spring based on experience), it is plain to see that the larger diameter spring is working harder since it has fewer working coils.  It is highly possible to use a Kel-Tec PF9 spring assembly (two counter-wound concentric springs) with the properly built rod ends, and never have a slide spring wear out in an R9 pistol.

Arne happens to be a very skilled engineer......but I don't think he will be making any recoil springs for the R9 either

[Faawrenchbndr]

Ok,........