Strange problem with HK45.
Ok, so I have an HK45 that I have shot probably 150 rounds through only(fmj). I purchased some Hornaday 230 grain FTX hp ammo. Loaded the gun up with it and cocked it, putting one in the chamber. Later, I pulled the slide back,(as I do all the time to check if one is in the chamber) and it was extremely hard to move the slide back to check the chamber. I also noticed, once I checked the chamber, and the round is in, that the slide sticks and does not move forward---I had to push it forward into battery. I tried different rounds out of the box, and tried with 2 rounds in the mag, and full, etc. The gun always does this (very tight and have a hard time checking the chamber). I pulled very hard(with the round in the chamber) and it will cycle all the rounds in the magazine, but it seems very very tight--once the round is chambered. I have not shot the ammo yet--not sure if it will have problems or not, but like i said i can--with great effort, cycle through a mag by hand.
What do you think is happening?? Is the gun just tight because it hasnt had any hp or much of anything run through it???