Quote Originally Posted by FPoole View Post
The brass rod thing won't be accurate either. You need a pin fitting hone. Sunnen makes the good machines here. You can buy a mandrel and use your own lathe, I suppose. I had a TX tube honed on said machine, years ago. The operator sets the thing up for the 1" bore and makes a very few seconds of strokes, to test the pattern before going all the way. Puts a beautiful crosshatch on the cylinder walls just like AA tubes have. My tube was perfect except for some marks where the bear trap notches are cut in. There is also the spot on the inside of most TX tubes opposite the cocking shoe slot, but this is never in the stroke of the seal. As long as the extreme spread for a shot string of 20 or so doesn't exceed 15 fps, I wouldn't worry. A barrel can also make the velocity spread change, so how do you know which it is?
Professional honing tools are obviously the best solution, but they are not available to most of us. Many have access to a lathe, so fitting a brass lapping plug is a more likely option.

Its not only about velocity fluctuations, its about guns that tear up seals, dont make power, leak lubricants past the piston seal and burn up piston seals fast.