Chambering????????
- Thread starter muzzle flash
- Start date
- Location
- Hillbilly shack in the boonies
The fella that did my Gaillard barrels first measured it all up to be certain the barrel was to spec, and then he used a match reamer to finish the job. And to finish it all off he bead blasted it to a nice satin finish, with a target crown also. And they shoot great , one is a .308 f-class, and the other a custom 25-06 with a magnum sporter profile.
Ted makes a wonderful barrel thats easy to clean (lapped bore)and holds accuracy when warmed up a bit.
Frank
Ted makes a wonderful barrel thats easy to clean (lapped bore)and holds accuracy when warmed up a bit.
Frank
There are a couple of ways of setting up for chambering.
One method is to center on the bore of the barrel and cut the chamber in line. Usually the chamber is drilled out undersize or a roughing reamer is used, and then it is finished to the correct headspace with the finish reamer. This is usually set up on a center and a steady rest is used.
Another method quite popular with the Benchrest crowd is to hold the barrel in the headstock of the lathe with a couple of inches of the barrel sticking out. I use a 4 jaw chuck in the headstock with a piece of 1/8 inch brass rod around the barrel. This prevents the jaws from holding the barrel at a particular angle. I have a 4 screw spider in the tail end of the headstock. Then using a test gauge graduated to the one ten thousands of an inch, the throat area of where the chamber will be, is indicated as true as possible. The muzzle end is also set as true as possible. Then the chamber body is bored out slightly undersize, the chamber is finished with the finishing reamer, and the barrel is threaded and fitted to the action all in one set up. The reamers require removable pilots with the correct pilot for that particular barrel.
One method is to center on the bore of the barrel and cut the chamber in line. Usually the chamber is drilled out undersize or a roughing reamer is used, and then it is finished to the correct headspace with the finish reamer. This is usually set up on a center and a steady rest is used.
Another method quite popular with the Benchrest crowd is to hold the barrel in the headstock of the lathe with a couple of inches of the barrel sticking out. I use a 4 jaw chuck in the headstock with a piece of 1/8 inch brass rod around the barrel. This prevents the jaws from holding the barrel at a particular angle. I have a 4 screw spider in the tail end of the headstock. Then using a test gauge graduated to the one ten thousands of an inch, the throat area of where the chamber will be, is indicated as true as possible. The muzzle end is also set as true as possible. Then the chamber body is bored out slightly undersize, the chamber is finished with the finishing reamer, and the barrel is threaded and fitted to the action all in one set up. The reamers require removable pilots with the correct pilot for that particular barrel.
- Location
- Calgary, AB
guntech has nailed this dead center; as per his avitar!
I prefer the method described by guntech. To provide a reference to use when adjusting the barrrel for centering with th axis of the spindle, I use plug gauges in the bore - bring the indicator up to the plug gauge. I purchased sets of these from www.meyergage.com for very reasonable prices. The barrel is centered at both ends, so that it runs with as close to "0" runout as possible when the lathe is turned over. Reamer is held in a floating holder. Not using a pressurized oil system, the reamer is drawn frequently, cleaned, re-oiled, and chips cleared from the bore.
To answer the original question- It is normal to either bore or drill the chamber prior to reaming. It's faster and saves wear on the reamer. Some may use a roughing reamer but most do not.
As to whether boring or drilling is best, I doubt that it makes any difference. A properly ground drill will follow the bore perfectly. If the bore runout is zero, the drilled hole will be as well. Even on a crooked bore, thedrill bit will flex enough to follow quite well.
One friend uses new Dormer drills and when the bit is dulled, he buys another rather than trying to resharpen. He figures dormer is better at it than he! Not bad reasoning, They certainly can do better than I can!
Most gunsmiths have individual preferences as to how things should be done. If the final results are good, so is the method. Regards, Bill.
As to whether boring or drilling is best, I doubt that it makes any difference. A properly ground drill will follow the bore perfectly. If the bore runout is zero, the drilled hole will be as well. Even on a crooked bore, thedrill bit will flex enough to follow quite well.
One friend uses new Dormer drills and when the bit is dulled, he buys another rather than trying to resharpen. He figures dormer is better at it than he! Not bad reasoning, They certainly can do better than I can!
Most gunsmiths have individual preferences as to how things should be done. If the final results are good, so is the method. Regards, Bill.
