How much before change

[RRMan03]

How much full power 10mm in a Glock 20 and Glock 29 can be firedd before damage with the factory recoil spring? I do not shoot them a lot and I do shoot the low power a lot. If I changed to a strong spring the PPU ammo probably would not even throw the slide. That ammo is probably subsonic.

[The_Shadow]

You will need to collect some spent brass from them inspect to see if any issues exist such as "SMILES"!  If you see "SMILES" you might need a stronger spring and better chamber support for those loadings!

Take note of how far the brass is thrown using the factory RSA, if over 15' you might need a stronger spring setup!

The nice thing about a non-captive spring setup is the ease of making changes!  I like my Wolff non captive setup and use the 21 lb spring set almost exclusively, from mild to wild!  10mm, 40S&W, 357Sig, 9x25Dillon   

[4949shooter]

I have the 20 pound captured RSA from Glockstore in my 20SF. It feeds the PPU like a champ.

My shooting buddy says it doesn't throw the brass as far as when the stock spring is used.

[RRMan03]

Thanks for the opinions and the input. That is what i need. I know i am going to have to go to a stronger spring. Probably somewhere from 20-22 I would think. With most of my shooting lower power would you recommend the 20 instead of the 22.

[4949shooter]

From my experience most definately.

The 20 pound spring also cycled Hornady 180 XTP like a champ. It did not like the Underwood 180. I am unsure at this point if it was a gun/spring issue or an ammo issue.

[sqlbullet]

I have a factory mag in my G29 and run full power stuff.  No issues.  I do see the occasional smile on brass, which may well be remedied by a stiffer spring.

In other words, I don't know that you will ever damage the gun if shooting max loads from new brass that are within spec.  You will see more brass that can't be reloaded.  YMMV