I bought a new 45 JHP several months back and have run into a strange problem with the trigger pull. Since new the trigger gets stiffer the more you fire it, until it is almost to hard to pull. I do not fire mag after mag to overheat the gun, maybe 15 to 20 rounds in 15 minutes or so, then a 15 to 20 minute break. I shoot on a public range with breaks scheduled ever 15 minutes. I have smoothed out the ends of the metal pieces under the right grip and lubed the mechanisms. The trigger pull is acceptable when the pistol is first fired. The trigger pull does return to this acceptable pull once it is cooled back down. I'm not a gunsmith but have worked on many firearms including rebarreling bolt action rifles, drill & tap receivers, forge bolt handles, etc. I do plan on sending it in but thought maybe others here have had this same issue.