Macay, Buffalo Bore recommended heavier springs in the Glock 20 in 10mm with their 220-grain cast loads and they also said shot-to-shot velocity variation went way down. Just as you experienced. My accuracy improved with the heavier spring and 220-grain cast loads. Ordered a 22# spring for my Springfied XDM 10 MM

This quote from BB that SU35 posted explains it better than I can

https://www.24hourcampfire.com/ubbt...glock-10mm-with-heavy-loads#Post16891543

Last edited by kk alaska; 09/07/22.
kk alaska

Alaska 7 months of winter then 5 months of tourists