I recently picked up a used USP Compact 45 LEM and wanted to convert it to LEM Light. I ordered the needed parts from HKparts.net. I had read all the posts related to what a PITA the trigger return spring is to install, but I am my department's certified armorer for Glock, Sig classic series pistols, Remington 870, M16/AR15, and HK MP5 & UMP; so thought how hard can this be? Well, after over an hour of messing with it yesterday with a friend's assistance, and trying everything from tiny needlenose pliers with the channel cut in them, to assorted tweezers, angled hemostats, and other odd assortment of tools with no sucess; I had a brainstorm last night. The entire problem seemed to be the spring legs are not long enough to manipulate into place, so the simple solution should be to lengthen the legs. My intial method of attempting this was going to be putting small diameter roll-pins on the spring leg extensions. I raided the department armory this morning, and the tiniest roll-pins that came to mind were those used to hold in the gas-tube into the front sight post on an M16/AR15. The spring legs were a looser fit in these pins than I wanted, and even crimping them did not help. I gave it a try with them anyway and they popped off as expected, allowing the left spring leg to drop down in the frame as usual. I searched around for something else to use, and decided on the plastic straw that comes with a bottle of Break-Free CLP. The small diameter of the hole in the straw was a relatively snug fit on the end of the spring leg. I cut the straw into 3/4 inch lengths of tube with the wire-cutter portion of the needle nose pliers. This crimped the end of the plastic tube, now making it a very snug fit on the spring legs. There was no way it was coming off without being yanked. I was still concerned that the tubes would be too flexible and bend too much. I dropped the TRS in place with the length of tubing mounted on each leg, and the trigger duct taped forward. The right leg had no where to go except behind the trigger where it belonged, and the left leg could physically not go anywhere except remain vertical against the frame. I put downward pressure on the top of the spring with a wide 1/8 diameter flat punch, slid the trigger pin in place, took the needlenose pliers and yanked the tubes off of the ends of the spring legs. Everything worked perfectly, the entire process took less than two minutes, and the only tools used were the needlenose pliers to cut the straw and to remove it from the spring legs, and the punch to apply downward pressure and line the spring up with the pin. All by myself with no extra arms, no vise, no specially cut pliers, no wasted time, and best of all no cursing!
I'm sure this would also work with my intital idea of roll-pins too, if those in the appropriate diameter could be found; and any type of tool could be used to put downward pressure on the spring. I just happened to have the 1/8 inch flat punch within reach.
I'm sure this would also work with my intital idea of roll-pins too, if those in the appropriate diameter could be found; and any type of tool could be used to put downward pressure on the spring. I just happened to have the 1/8 inch flat punch within reach.
