Recoil Spring and Failure to Return to Battery

[delphidoc]

I've got a 97B with about 2000 rounds through it. I've been having more and more instances of the slide failing to return to battery. The rounds would be partially in the barrel chamber. I would have to smack the slide home and sometimes cock the hammer when this happened. This problem appeared before converting it to SAO with CGW goodies- 5SAO trigger, extended firing pin and springs, 13# hammer spring, race hammer, etc. I have polished the feed ramp, made sure the slide stop is not hitting the rounds, cleaned the extractor hook, made sure the extractor housing wasn't gunked up, and made sure I wasn't limp-wristing. This happened with all of my magazines, strangely almost always after firing the top round. The problem has gradually gotten worse over time.

I think I've fixed it. Woff lists the stock recoil spring as 13#. I tried a 16# spring without much if any improvement. This week I ordered an 18# recoil spring and a set of +5% magazine springs. I put in the 18# recoil spring today. I was going to change out the magazine springs but the spring ends require some tweaking to fit the followers and magazine base locks. I ran out of time and went to the range today with just the 18# recoil spring installed but with the stock magazine springs.

I put 100 rounds through the 97B today without a single failure to return to battery. I wasn't allowed to stand outside of the shooting cubicle but I stepped back as far as they would let me. The cases seemed to be ejecting slightly backward and outward at least 5-8 feet. Hopefully this means I've fixed my problem without the 18# spring being too stout. Wolff sells a 20# spring that I won't have to try and then worry about battering the slide or damaging the slide stop.

[Tok36]

Maybe the orignal recoil spring was going bad. Low round count for that but it could have been a bad one from the start. Glad you got it running again.

[Joe L]

I remember something similar with mine, even with lightly loaded ammo--I remember putting a heavier spring in mine.  It was too light from the factory to cycle reliably and I think I wound up with either a 16 or an 18.  Been fine ever since.  I think maybe the 97 chambers are not as sloppy a fit as some pistols so the recoil spring has to be a little stronger than expected. Mine would throw the casings 20 feet with the factory recoil spring and a light hammer spring.   This is just the opposite of the P series pistols which seem to have heavy springs for stout defensive/service loads and they won't let the slide come back far enough for the brass  to hit the ejector, with puny match ammo.  I lighten the springs only enough to get them to cycle full stroke now, with the lightly loaded ammo I intend to shoot most.  Or in the case of the 97 (only one so far), go heavier.

In other words, I don't think there is anything unusual or unique to your particular CZ-97.  One approach is to save your 97 springs for a 75 and save your factory 75 springs for a 97.  Or something like that. 

Joe 

[SPO1SHADOW]

I have a 97B that is about 5 months old. I will assure you that the OEM recoil spring was not 13 pounds. Not saying yours was not but on my new gun it was very hard to cycle the slide and the gun exhibited A LOT of muzzle dip when the slide returned to battery and ejection was weak with 170 PF loads. I purchased a 15 pound spring and started having the problem you describe after several hundred rounds or after the 15# spring was well broken in. The 15 was WAY easier to cycle than the original and empties were flying at least 8 feet away. I believe the newer factory spring to be at least 18# or better so I cut off 2 rounds of the spring and found it to be perfect. My OEM is a flat wound spring blue in color. I would think something in the 18 to 20# range after break in would be about right. When I wear this one out I may go for an 18# variable spring and see what happens. The 97B is definitely a different beast when it comes to recoil springs.

[ffr1910]

factory ammo or reloads? to much COL will cause the bullet to engage the rifling early and hold the slide out of battery. I had this problem with my 97 with LRN reloads. SWC bullets never have this problem since they are truncated-Bill

[delphidoc]

I only use factory ammo. I've used Aguila FMJ and Blazer Brass FMJ. I checked for clearance of the round tips at the slide stop with the slide off, and plunk tests have all been OK.

[Sooltauq]

Good info -- my 97 is starting to approach those numbers and I'm going to keep this solution in mind.

Of course, it also means that I need a second 97 . . . . .

[1SOW]

Gunsprings.com (Wolff)  shows 14# as "standard" for the 97B.  You have to open the 97B spring chart and it shows all the springs available for 97B.

Glad you got it running.

[SPO1SHADOW]

A friend of mine just bought a new 97B and the recoil spring in his was a regular round wire spring and not nearly as stiff as the one that came in mine. I am at the point now I think my gun came with the wrong spring in it or an attempt to fix this problem but it is absolutely not a 14 lb. spring. I am going to call CZ and find out if my gun was supposed to come with a blue flat wound spring. This spring looks just like the one that comes in the P-09.

[olfarhors]

my 97 BD has the flat wire spring and so far has ran like a sewing machine an my goodness on how many different self defense rounds and target rounds, SWC, FP, RN, JHP, its north of 2000 round by a bunch, should be around 4000-5000 actually.
the weapon is very smooth as well.