I found this on another site and thought it was interesting and helpfull...
"I found an inexpensive way to improve the patterns on my .410 and my 12 gauge NEF Pardner shotgun barrels. My .410 is a fixed-full choke, and the 12 gauge is a fixed-modified choke. No matter which shotshells I used, both barrels were shooting consistently low, compared to the point of aim. They both had similar holes in their patterns too.
These problems were slight, but I wanted to correct them, if possible. I wondered if there might be a common reason for these two barrels, of extremely differing bore sizes, to have such similar pattern characteristics. It turned out that they did. At least that is the conclusion that I eventually came to.
Here's how I figured it out. First, I inspected the bore of each barrel and found that both of them showed more machining marks than other barrels I had seen. Secondly, in the inspection process I found that the threading for the screw-in sight beads had left several jagged burrs that I had not noticed without my reading glasses on. (These threads go all the way through the barrel wall on the standard weight NEF barrels.)
After a thorough cleaning, I took out a small, but very sharp, stainless steel pocket knife and painstakingly cut and scraped the excess metal from the threaded area inside each barrel. I hand-chamfered the edges with fine emery cloth, taking care not to leave any sharp edges. Next, I burnished both barrels with 0000 steel wool, in accordance with burnishing instructions found at the following website:
http://www.gunnersden.com/index.htm.shotgun-bore-polishing.html It was time to put my work to the test. I test fired both barrels at the range at 25 yards for the .410, and 40 yards for the 12 gauge. I didn't do a complete pellet count this time. I just did a point-of-aim to point-of-impact test, and compared the general look of the patterns to earlier tests which I had done before the deburring and burnishing process. Both barrels shoot dead-on to the point of aim now, with the center of the pattern impacting within a couple of inches of the center of the target.
Success--it feels good I love my NEF guns even more now. I have three. In addition to the .410 bore and the 12 gauge, I have the Huntsman .50 Cal. muzzleloader. It is superb!"
The above was posted by "Tenderfoot"on another forum, I found it worth the read....<><.... :grin:
