Jimmyk over in the Shot String Database thread asked me about lapping a barrel. I decided to answer his question here so as not to get too off-topic over there. This last weekend, not being entirely happy with the fliers I was getting in every target, I decided to bite the pellet and remove the barrel from the .25 and lap it. I followed Greg Davis' method for lapping a barrel. http://www.network54.com/Forum/581291/m ... l---------
As per Davis, I used Mothers Mag wheel and Aluminum Polish and a brass or bronze bore brush, size .22. I would use a Dewey Nylon coated rod for .22/.25 which you can get at PA. I only had a regular metal rod which I wrapped with black Gaffers tape...it's a fabric based tape, not duct tape. You don't want to scratch or otherwise damage the barrel; air gun barrels are a lot softer than those in powder burners.
I took several 1.5-2 inch Mothers saturated paper towel strips and I rolled each, one at a time, onto the brush, taking care to completely cover the entire length of the brush. Use whatever length makes for a snug fit when rolled onto the brush. I took the barrel completely out of the breech and used a table top to stabilize it. You can leave it in the breech but I would suggest lining the breech with some paper towel to keep the mothers from getting up in there. Be sure and remove the O-ring in the breech end of the barrel before starting. Following Davis' protocol, slowly run the brush down the barrel ...do not exit either end for about 7 strokes. I count a stroke as going from breech to muzzle, back to breech. Pull out after the 7th stroke and notice how black it is! Run a couple of patches down the barrel to remove the residue and repeat , changing paper towels each time, until you've done maybe 28 to 35 strokes, again running patches after each 7th stroke.
I then ran patches soaked in Goo Gone until they emerged fairly clean then followed with several dry patches. NOTE: The Mothers will clog the O-ring channel and the air port so clean them out good with Goo Gone on a cotton swab then dry swabs. Coat the O-ring with Silicon grease, reassemble and sight in. .Use pb177's reassembly method to get everything realigned properly.viewtopic.php?f=19&t=1896&p=10998&hilit=barrel+reassembly#p10998
look half way down the page....important stuff here!
NOTE: It will take 4-5 magazines (about 40 shots) to re-season the barrel and get groups to tighten up. I saw a big, positive difference by the 5th magazine! I got my old barrel back after doing this!
It was well worth the time and it was kinda fun to do.
I would recommend it if you are having trouble with fliers or would just like to see if the groupings can be improved. Otherwise, if it ain't broke, don't fix it.
Hope this helps...KP