The test was started using .22 Lobo balls and end cap 0.030, moving up in clearance with each shooting group. No significant change in groups due to diameters. Groups varied from dime size to quarter size which is characteristic of balls that vary 5.44mm to 5.54mm depending on which side is measured on each irregular ball. None are perfectly round or even close.
Second test followed using Daisy wad-cutters starting with 0.090 clearance and moving downward in clearance diameters. Again no change in shooting group averages. All stayed within dime size groups.
Therefore..... after making a second rod of steel, sized to the bore and using it to align the brake end cap orifices..... I can use any size end cap that I choose for quieting if necessary. At least down to 0.030 clearance around the projectile.
I will probably choose either the 0.090 on the none-venting 7 inch brake or the 0.040. The difference in quieting is not that much..... a ball hitting a wad of old cloths and shirts at 50 feet makes more sound than the gun does with either end cap to give an idea. Are we being sneaky or what?.......
-LarryS