I love the SLR-107’s from Arsenal because of the spring loaded firing pins just like Polytech’s. I have never worried about wearing out the spring. I think Heavy Metal said it best. Any spring or part for that matter can and will wear. I don’t think you will hurt the firing pin. The spring might wear out after thousands of dry fires. Get a spare or 2 and keep a count. Report back on the wear or lack there of.
There is no place to buy a spare firing pin spring for an SLR107. Until this part becomes available I wouldn’t dry fire your rifle thousands of times. Right now the only way to get a spare firing pin spring would be to buy another SLR107. Seriously, Arsenal/K-VAR doesn’t have any and never did have any when they first released the SLR107 years ago.