I just installed my second Vortek kit in a Beeman R1 this month. The first went into a San Rafael R1 in .177 that i picked up from the classifieds. After replacing cracked breech seal, I figured that the 30 year old seal might need some attention also. The gun looked ok on the chrony, but it stuck in my mind so I opened the gun up. Originally the gun shot an grouped ok. I was shooting H&N FTT's at mid 800's, but the thing kicked like a mule and had a lot of vibration. The transformation was amazing! The velocities were about the same, but the shot cycle was quick, smooth and quiet. The kit made the gun a real shooter, much to the dismay of the neighborhood squirrels. This past week, I ran my everyday gun, a current generation Beeman R1 in .20, across the chrony. I felt that it had been very easy to cock lately. My suspicions were proven when I saw the low 700's. The gun is only 2 years old, but its the one I always grab. I started counting empty tins and estimated 7000 shots downrange. I guess I got my money out of that spring... I pulled it apart to find that the spring had very little preload left. It had relaxed quite a bit, and the seal felt very loose. I cleaned the inside of the tube and reassembled the gun. I was forced to compress the spring and screw on the end cap by hand when my homemade spring compressor failed... I am so NOT a carpenter. But, with a little brute strength, I got it back together. I shot it for about 20 shots with it dieseling and going supersonic a few times. The gun started to settle down a bit so I began to try to zero the scope at about 40 yards, After a handful of pellets, the gun was holding zero pretty well, with no more dieseling. It was really early in the process, but i couldn't take it. I set up the chronograph. I was amazed! The gun was shooting H&N FTT's at about 715 fps. After the kit, that number jumped to over 875. The shot cycle is very crisp, it is not the docile gun that it was with the worn spring, but it is still a pleasure to shoot. I will be ordering another kit, just to have on hand. These products are hard to beat.