chambering question

[woodbutcher]

I am preparing to chamber a barrel and I want to experiment. I tried to dial in the barrel using the Gritter's method; I got mixed results. I think his method has a lot of merit, but I am having a little difficulty getting repetitive readings. I have used a range rod with two tenth indicators; one at the entrance of the bore and the other on the unsupported end. The muzzle would run wild with both methods. Which method do you think would be best. I know most of you indicate both ends and I have done this also, but I am always trying something different.

 

[ultramagmed]

I have only chambered three barrels in my short tenure as a wannabe gunsmith. I have only chambered with both ends indicated in and see no reason to change. I use a tap handle that has been faced off true and a morse taper reamer pusher that I built to chamber, a copy of one that frwillia has pictures of in a past post, only after pre-drilling and taper boring. All three shoot very well.............I'm content with my results. I'm not gonna fix what ain't broke.

Good Luck,
Med.

 

[Rustystud]

Both ends need to be secure..

Maybe Gordy will step in.

From viewing Gordy's video it appears that he indicates the tenon end off the rod at two locations. He then indexes the muzzle so the barrel will be in vertical mode when fitted to the action. I beleive you will find Gordy also has a Cathead at the end of his headstock holding the muzzle end of the barrel preventing any barrel flop..

Gordy gets good results. I beleive Greg Tannel does his in a simular manner.

Nat Lambeth

 

[Jkob]

This kind of gets me to thinking. I think I do understand Gordy's method but one thing I would be concerned with is the bushings on his rod. I have run into barrels of different diameters that vary by a few tenths from one maker to another by the same caliber. Is it necessary to buy a whole boxfull of bushings?

Jim

 

[Rustystud]

Pilot or no pilot..

Jim:

With all due respect this has been hashed and rehashed many times. There are many philosophies on this subject.

According to Dave Kiff I have one of the most extensive collections of pilots for calibers from 20 through 45. I have about 100 pilots in .0001" increments for each caliber. In my opinion a good fitting pilot will guide a reamer in a floating reamer holder as close as one can get. After cutting a chamber I have gone back to check for run out and it is almost impossible to detect.

Butch Lambert, Jackie Schmitt and others dial in off the bore and prebore up until the last few .001" and the finish by reaming.

Both methods produce good results.

I will be the first to say if you don't have the right reamer pilot for the bore diameter then you should not use a floating reamer holder. The reamer may tend to yawl or pitch cousing out of round chamber. This is noted more when using a highspeed flush system and chambering at higher RPMs.

Nat Lameth

 

[Jkob]

It ain't the reamer pilot I am concerned with. I was wondering if the range rod he uses for indicating in the barrel has a number of different bushings due to the difference in the bore sizes from one maker to the next. Kind of a dumb question and I think I found my own answer.

 

[Rustystud]

Use the same pilot

Jim:

I use the same pilot on the Range Rod, Center Drill, Reamer, Counter Bore, Facing tool, Crown Cutter.

Sometimes barrels are tighter in the muzzle than the tenon end and I have to use different pilots.

It is very important to clean the barrel before fitting the propper pilot. If there is any lapping compound left in the barrel it will find its way between the pilot and the bore. It will score the rifling and can make the bushing bind up. Measurements in the .0001" are precise with regard to the measuring ability most of us have in our small shops. This is often done by feel.

The top barrel makers mark on their barrels what the diameter is in the lands and grooves. I find their bore measurements often do not to match what my pin gauges or pilots say they are. They may be off by .0002 usually they say they are smaller than they really are. Most of the top barrel makers say their barrels vary in diameter less than .0003 for the length of the barrel. This is tested by air gauging the barrel. I rarely see more than a .0001 difference between the muzzle and the tenon end and can speak of what is between. I admit I routinely only use a couple of different barrel makers barrels.

Since long gun drills tend to wander the actual bore location in relation to the barrel OD may wonder several .001 between the tenon and muzzle. This has been proven by my cutting barrels off and not finding the bore in the center of the barrel.

This is a very interesting subject and I always enjoy talking to folks like Tim North, Jack Kreiger, Mike Rock, Dan Lilja, Frank Green who are in the barrel making business.

Nat Lambeth