I think you should practice with it alot and replace the spring when it begins to fail to feed reliably. Loading the mag tube to its full capacity won't wear out the spring. Springs are worn by many compression and decompression cycles over a long period of time, NOT by constant compression. If this is a LEO weapon, I'll assume it's being loaded and unloaded on a daily basis. That being the case, the spring will malfunction sooner rather than later and I would replace it with a quality Wolff spring. At any rate, don't load it halfway, load it up to the max. HTH