THe first time I saw the 110-grain +P+ load, and that was the first +P+ load I knew existed, it was the issue round for Dept of Treasury SAs; not IRS or Secret Service but Treasury investigators. Their issue weapon was the Model 36 with 110-grain +P+ loads. Based on one of their firearms instructors in the St. Louis office when I was shooting with him, and I believe I saw this elsewhere later, S&W voided the warranty on their 36s because of the pressures of the loads. He gave me a couple of boxes of it at the time and I seem to remember that it was Winchester. Normally, they practiced with and qualified with standard velocity .38 special loads, but my friend found that when he had them qualify with the +P+ load a lot of them had trouble so he started requiring that they shoot their qualifications with the duty +P+ round. Pressure was 23,500 psi. Firing the +P+ was definitely noticeable in the Model 36, but not as fearsome as some claimed. It certainly wasn't as bad as the first time I fired 125-grain JHP in a Model 66 2.5 inch. One interesting aspect of the +P+ GI ammo I mentioned to start this thread is that it was loaded by IMI.