STI 2011 - Fenix 147gr 9mm - Wolff springs

[Mattlws6]

Looking for thoughts and suggestions on playing with spring rates on my 2011.

 

STI informed me that it comes factory with a 10lb recoil spring, and I weighed my slide at 12.1 oz.  (pretty standard)  With the addition of a Wilson Shock Buff and 9lb Wolff recoil spring, it runs slightly better with standard 115gr factory 9mm. (Bulk practice ammo)

 

For competing though,  I run 147gr -P 9mm (129 P.F) and this is where the lighter spring really shines.    https://fenixammo.com/

 

Again, the 9lb recoil spring seems to work fine for both, but my darn curiosity got the best of me and after experimenting with the conventional 8lb spring, the recoil and reset feel PERFECT.   Only issue is that occasionally the gun will fail to strip the last round from the magazine regardless of ammo.    

 

I am looking for my best option on making the 8lb spring run reliably.   My gut tells me that it could be magazine related, but I am almost wondering if dropping 2 lbs from the recoil spring is too drastic without adjusting the mainspring and/or FP spring.   

 

Any input from someone with more experience is much appreciated.   Going to the range and dumping ammo waiting for malfunctions is getting expensive.

 

Thank you!

 

My thoughts are:

- Magazine issue?

- Too much mainspring or incorrect FP spring?

- Shock Buff stopping slide from coming back all the way?

- Maybe a progressive recoil spring will help return the slide that extra bit it needs?

- Weight needs to be removed from the slide?

 

 

[Clint U66]

When you say it fails to strip the last round, does the gun go to slide lock or does the slide move forward and contact the cartridge but not move it forward into the chamber?

[Stymie12000]

Like Clint said. Check to make sure the mag followers are not moving the slide stop at all. I've seen the followers move the slide stop enough to slow the slide down but not enough to lock the slide. 

 

If it's not that, then could be mag tuning and/or extractor tension. 

 

8# spring should work just fine whether its variable or standard. I've gone down to 6# without feeding problems with my 2011. 

[Mattlws6]

I am going to check if the follower is contacting right now.   When I get the hang up, the round is half way out of the mag and up the feed ramp.   I can tap the back of the slide and it will go right into battery with the round.   That's what made me think originally it needed a bit more spring.