Guide Rod Assembly for Glock G26 G27 G33 G39 Pistols

That is extreme for sure. I would recommend as high pressure ammo as you can find. 9x19 doesn't have enough pressure to work a brake but it adds mass out past the slide that will cause lock unlock issues. Bulk practice 115 grain bulk tends to be just inside sami specs for the round so it is pretty low pressure. I would try higher pressure ammo or look for ammo that is the same pressure as the defensive version of the ammo. Going lower on the rate will help a little but ammo pressure is going to help as well.

20lb rate will be the highest we offer and will offer the most rate for help with muzzle flip from recoil.

Yes the G1-5 sub compact 26 27 all share the same rod.

I recommend and use the 20lb, not sure why anyone would say stay at the stock 9mm level when the 40 is a much higher pressure round but the internet is full of experts. The 9mm, 40 and 357sig all get the same spring assembly, the 9mm needs a 16lb for general use and so they all get that rate to stock one spring for multiple models which keep costs down at the factory. If your running lower than standard pressure 40 ammo then yes stay with the stock rate. IF your running full pressure or higher 40 go with the 20 or 18lb rates.

They can be disassembled if you would like, they are red loctited at assembly here so heat is needed to break the locking.