Ray,I used bench grinder and then progressively finer grits of sandpaper for mine. 100 turns clockwise and 100 turns counterclockwise for each grit from 60 to 2000.http://www.gatewaytoairguns.org/GTA/index.php?topic=112013.msg1087227#msg1087227Is it possible the bore of the barrel is not centered and that is why you're slightly off?Taso
Quote from: rayandkerry on September 12, 2016, 06:42:27 PMRay, are you moving the drill in a random figure eight pattern as you go? It's counterintuitive but that will give a more uniform result than attempting to keep the drill straight. For example, I swing the drill out to angles as much as 30-40°.Otherwise the biggest issue I see (based on helping a few people by phone and personal messages) is applying too much pressure in an attempt to make the process go quicker. What that does is push steel into the bore and leaves a burr. The idea is to apply just enough pressure to keep the brass head in contact with the crown. Let the abrasive do the work.To confirm there is no burr, push a couple of pellets through. If you can feel even the slightest resistance as the head emerges from the muzzle, it needs to be reworked. Now of course if the muzzle is choked, there will be some resistance for the last inch or so but there should be no increase in resistance as the head emerges.Quote from: rayandkerry on September 12, 2016, 06:42:27 PMOr maybe my technique was bad...it was surprisingly difficult to do, the cleaning rod kept wanting to bend.Please explain. Unless you are referring to pushing pellets through, I don't know where a cleaning rod comes into play.
Ray, are you moving the drill in a random figure eight pattern as you go? It's counterintuitive but that will give a more uniform result than attempting to keep the drill straight. For example, I swing the drill out to angles as much as 30-40°.Otherwise the biggest issue I see (based on helping a few people by phone and personal messages) is applying too much pressure in an attempt to make the process go quicker. What that does is push steel into the bore and leaves a burr. The idea is to apply just enough pressure to keep the brass head in contact with the crown. Let the abrasive do the work.To confirm there is no burr, push a couple of pellets through. If you can feel even the slightest resistance as the head emerges from the muzzle, it needs to be reworked. Now of course if the muzzle is choked, there will be some resistance for the last inch or so but there should be no increase in resistance as the head emerges.Quote from: rayandkerry on September 12, 2016, 06:42:27 PMOr maybe my technique was bad...it was surprisingly difficult to do, the cleaning rod kept wanting to bend.Please explain. Unless you are referring to pushing pellets through, I don't know where a cleaning rod comes into play.
Or maybe my technique was bad...it was surprisingly difficult to do, the cleaning rod kept wanting to bend.
OK, old topic, I know. But I did finally try the barrel treatment and pretty much wrecked the thing. Shoots terrible now. I recrowned, still bad. Chopped the barrel to just under the existing crown to try and get a fresh edge (I've only removed about a half inch total so far) and recrowned a third time. Still terrible.Seems like, no matter how much I go at it with a brass screw, one side of the barrel just won't get where I can see the grooves and lands clearly cut into the edge of the crown when looking straight down the barrel (although they are clearly visible leading up to the crown when looking sideways into the barrel). Maybe I abraded too much. Not sure if I just didn't have a good enough stop near the muzzle or what. Or maybe my technique was bad...it was surprisingly difficult to do, the cleaning rod kept wanting to bend. I'm usually pretty handy...Anyway, pretty frustrated now. I had it shooting very nicely and liking more pellets from just chopping off the piloting tool damage and recrowning. Id definitely recommend that to anyone who gets the 177 Marauder. It was awesome after that.Not sure what to do now. Maybe i should chop off another 1/2" and recrown again? I might even be willing to fork out some $ for a better drop in barrel and be done with it, but it appears marmot militia only sells 22 barrels now... didn't see any 177 on their site.Any suggestions on what to do next are welcome!
wish I lived closer and had a before and after look on your barrel... just lapping should not be that kind of prob... these barrels are soft but are still pretty hard... but some crosman barrels have pretty light rifling... in the end you have to evaluate what each barrel needs individually...How many pellets have you sent down range after lapping... is it bad with all pellets... heck are the .177 barrels choked..? check all the other things that it could be like an injured barrel o-ring leaking or the transfer port not sealing... maybe a loose barrel grub screw...when you shortened the barrel how did you mod the shroud and cones is it clipping now..? check all the things that can change while removing and installing the barrel...when you lapp the muzzle end gets very few few strokes it is the breech end that the rifling would be worn...?there is a Hammer forged .177 barrel that might be able to be modded for the Mrod if that is what you want but not cheap and the I think not cheap to have it machined to fit the Mrod...http://www.airgunspares.com/store/product/16155/BSA-Buccaneer-.177-Rifle-Barrel-Part-No.-16-9382/
I live really close to you Ray, but unfortunately I have never done much barrel work. If you need another set of eyes or moral support though, just let me know.