Those are my loadings for 180gr and 200gr XTP's, and I have shot them out of my stock G20 barrel at those velocities (1300 and 1200fps respectively). I do use a 22lb Wolff recoil spring. I would add that I have only done this with Long Shot and 800-X, and I use standard CCI#300 primers for the loads. So it may not work or be safe with other powder/primer combinations.
If you don't have a chrono, you should stick with book loads and in any case, work up carefully (0.2gr increments) to your max. I strongly suggest weighing every charge at these velocities, as small errors in thrown charges can cause big problems. Especially 800-X, since it doesn't meter well, needs to be weighed every charge.
The brass does get worked a bit more in the stock barrel, but as long as it isn't glock smiled (and I haven't yet had a glock smile from the loads I mentioned here) you can get several reloads from your brass at these velocities with little worry.
One other thing, the consensus is that 180gr Gold Dots over expand at 1300fps. 180 XTP's are good to go at that speed, though.
A handgun is only good for fighting your way to a rifle.