Hello, i just bought my first glock(19) and dont know much about them. My main concern is what type of ammo should i avoid using? Four seasons glock page says to never use reloaded and non jacketed ammo, is this true? I was at walmart the other day to get some ammo but all they had was the remington umc 250 box, it was a good deal but it was not jacketed ammo(clerk said and doesnt say fmj on box). I dont remember what the "u" standed for the the rest was "metal case" was this something that would of been ok to use? Thanks in advance.