I ordered three Middle Stems with Camlocks from Big Boys Hobbies, one for my Ace 250 and two for the GTI 2500. A Camlock stem was installed on Ace 250 and it worked fine. I tightened the Camlocks and there was no wobble in the stem with the sniper coil installed. It looks nice and I am pleased with the installation. Next, I installed a Camlock stem on the 2500 with the standard 9.5 inch coil but the Camlock had to be positioned about an inch away from the start of the taper near the control housing. That concerned me because for the heavier coil, I wanted to take benefit of all the available shaft. In tightening the Camlocks I found it was difficult to tell how tight the outer nut was because the plastic nut on the internal plastic cam had a seizing effect, so I used a touch of silicon grease to lubricate the joint between the two. That was a big mistake so DON'T DO THIS. The silicon grease resulted in making the joint between the outer nut and the inter cam too smooth and I ended up over tightening and cracking two of the outer nuts before I detected the problem. In order to correct this situation, I took the Camlock off the upper end, near the control housing, and then the stem could be positioned exactly as the original was, up against the taper, with the spring pins entering the proper holes. This resulted in no wobble at this joint. Originally, there was a wobble between the coil stem and middle stem which has been corrected using the single Camlock. I am happy as a clam.