They were designed to run in a box stock gun in proper working condition, without having to resort to buying extra power springs.
Yes they are fine for stock barrels.
Hard cast bullets are not "lead" bullets. I have personally shot very well in excess of 100K rounds of hardcast projectiles (years of USPSA competition) through various Glocks, primarily .45s, with zero issues.
If you want the last 100, PM me for details.
