I've Finished with my barrel liner preload tests and have come to the following conclusions. These are on my guns only I haven't tried it on others. So your results may be different.
I found that a preload of 20 to 25 inch pounds produced the most consistent and tighter groups. I also removed the O rings and made up Delrin bushings that I installed on the liners to keep vibration and movement to a minimum. I then removed the barrels and reinstalled them and found that if i didn't index them the same as they were before I pulled them they would change POI. One gun as much as 1.5 inches at 25 yards. I then rotated the barrels clockwise 1/4 turn and shot a five shot group. I did this till they were shooting where pointed. I then marked the barrels TDC so they could be replaced in the same location every time.
After all of this work I will now never remove the barrels unless there is a major problem. I think if you change barrels to change calibers you will have to tune all over every time. I'm kind of lazy and once the work is done and results are what makes me happy I'm done. Also it gives me a reason to buy another gun because we all know we just need one more gun.
I found that a preload of 20 to 25 inch pounds produced the most consistent and tighter groups. I also removed the O rings and made up Delrin bushings that I installed on the liners to keep vibration and movement to a minimum. I then removed the barrels and reinstalled them and found that if i didn't index them the same as they were before I pulled them they would change POI. One gun as much as 1.5 inches at 25 yards. I then rotated the barrels clockwise 1/4 turn and shot a five shot group. I did this till they were shooting where pointed. I then marked the barrels TDC so they could be replaced in the same location every time.
After all of this work I will now never remove the barrels unless there is a major problem. I think if you change barrels to change calibers you will have to tune all over every time. I'm kind of lazy and once the work is done and results are what makes me happy I'm done. Also it gives me a reason to buy another gun because we all know we just need one more gun.
