I have a 34 that has an offset drilled bore by .011 to one side and basically no crown whatsoever. It looks like it was just cut off and rough sanded. When I got it new it shot about 7" low and 6" to the right. A while back I corrected poi with one of the precision barrel bending techniques. lol. I've been occupied with other guns lately so the 34 has been collecting dust. I got it out, took the barrel off and chucked it up in my lathe and took about .075 off to get back to fresh meat.Thats when I noticed the bore was off center. This is where you come in. What if anything should I do next? Thanx in advance, Charles
making some recomendations and if your 34 has a 19.5" barrel? then it is a virgin barrel
you can drill the front inside of the barrel and use a polishing compound paste to make the crown smooth, how smooth? test it with a Q-tip, twist the Q-tip and if no fibers are imbeded in the new crown then you are good to go
CHOKE is another issue, to find out IF the barrel is choked put a pellet in the breech and push it with a rod, or a wood dowel down the barrel
at first the pellet meets resistance because of the skirt of the pellet, just measure your barrel and find the lenght and with the rod, measured at about 1' less the pellet will meet a tight spot
you can fell the resistance as the rod goes to the end of the barrel, if you do not feel it the barrel is not choked, then that is another issue and you NEED expert help
not to worry since other members will chime in
warren
PS: good luck
and remember "it's 30% the gun and 70% the shooter"
Yea, I've seen that one a few times. It looks simple, but is it effective? For some reason what Larry means by "trying to get that old rifle shooting a little better" and what I want to happen are two different things. I wanna see his before and after groups.
Its not uncommon to find bores that are slightly off centre relative to the barrel's outside diameter.
Its no big deal.As long as the bore lines up exactly over the transfer port and the barrel locks up nice and tight with the cylinder, you'll be ok.
If you do not have a 4 jaw chuck in your lathe, or do not want to send it out
January 19 2009, 9:46 AM
Try the Brownell's crowning tools. One comes with pilots in several sizes and there is another that uses pilots you make, so an airgun pilot for 0.177" can be easily made, There are commercial pilots as well as a pilot for .22" in RF and CF bores. Use the RF version and put some tape around it (the thin, transparent almost cell-o-phane tape type, if your gun is a .22"
Now, to clear up some points:
Crowns are protection for the barrel's accuracy, they are not strictly needed, as long as the transition from barrel to air is clean, the crown could not exist and the gun could still shoot very nicely. IF the transition is nicked, simply facing the barrel will correct the transition. Face it of with a very sharp, clean tool that leaves no burrs you need to enaure that the bore is concentric to the rotation. Warren's test is a good one, a Q-Tip should leave no residues in a well cut crown.
There is no magic to ANY crown: the dish, countersunk, round, flat, match, angled, none, all the crowns work well if properly done. Some have some specific uses and I have my preferences, but each one will also have it's own preferences.
Granted that a gun with a nicely cut crown looks better than a flat transition, so if you want to have tool for the job, go here:
If you do not have a 4 jaw chuck in your lathe, or do not want to send it out
January 19 2009, 9:48 AM
Try the Brownell's crowning tools. One comes with pilots in several sizes and there is another that uses pilots you make, so an airgun pilot for 0.177" can be easily made, There are commercial pilots as well as a pilot for .22" in RF and CF bores. Use the RF version and put some tape around it (the thin, transparent almost cell-o-phane tape type, if your gun is a .22"
Now, to clear up some points:
Crowns are protection for the barrel's accuracy, they are not strictly needed, as long as the transition from barrel to air is clean, the crown could not exist and the gun could still shoot very nicely. IF the transition is nicked, simply facing the barrel will correct the transition. Face it of with a very sharp, clean tool that leaves no burrs you need to enaure that the bore is concentric to the rotation. Warren's test is a good one, a Q-Tip should leave no residues in a well cut crown.
There is no magic to ANY crown: the dish, countersunk, round, flat, match, angled, none, all the crowns work well if properly done. Some have some specific uses and I have my preferences, but each one will also have it's own preferences.
Granted that a gun with a nicely cut crown looks better than a flat transition, so if you want to have tool for the job, go here:
