Dialing in muzzle end...am I on the right track?

[DSM]

Finally finished my outboard spider and used it to dial in the muzzle end of a Krieger 4 groove 6mm barrel. I think I am on the right track. Is my muzzle dial acceptable?

Do you dial in the chamber end first, then dial the muzzle and then go back and forth till both ends are acceptable?

I may fabricate a front spider to dial in the chamber end...anyone dialing in using a front and rear spider? Will a front spider provide enough holding power?

 

[Jerry H]

Establish a pivot with a soft metal ring between the barrel and the jaws at the mid point of the pilot where the chamber finishes. With the indicator inside at that same depth, dial for minimum TIR. Move the indicator back to the start and repeat. You now have the start and end of the chamber running on the same axis. You don't care where the muzzle ends up. If the barrel is crooked between these points, the reamer will wander at the mid depth. Since the reamer has a little taper, you end up with a straighter rounder chamber that is lined up with bore. Krieger barrels are pretty straight.

 

[DSM]

Thanks for the tips Jerry! I do have a 4ga copper ring between the chuck jaws and barrel.

Points taken on chamber end. The reason I dialed in the muzzle end was to test out the outboard spider that I just finished making. I found it much easier dialing in the spider rather than my 10" 4-jaw(Chinese Grizzly). I think the 1/4-28 spider set screws are much finer of an adjustment than the chuck. This is why I'm thinking about using a chuck side spider. Or maybe a Bison or Buck needed?

I never chambered a barrel yet, just getting set up with the basics and trying to absorb as much info I can on the process. Hopefully I can find a shot out 6mm barrel from someone to make a practice run.

 

[msalm]

When setting up a barrel to dial in through the headstock, I support the chamber end with a live center and the chuck (cat head/spider/whatever) jaws or screws not touching the barrel at the chamber end. Then I dial in the muzzle at the outboard end. Cut the barrel to within 1/2" of OAL beforehand as the bores do wander. After the muzzle is dialed in snug up the chamber end screws finger-snug and remove the tailstock. Dial in the chamber end (it will be within a few thou or less at that point). It saves A LOT of going back and forth if you are going to just dial in the muzzle and breech end and typically takes less than 5 minutes to get less than .0002" on both ends. If you're going to do the Gritter's method, you can then set up your indicator rod on the tailstock chuck and start dialing that in. I typically don't, but I do drill out the majority of the chamber, dial in on the throat area with a Gritter rod/bushing setup then bore the drilled area so the reamer has a straight shot into the chamber area. It works well and you can check ahead of the throat to see if you need to adjust the muzzle end to get a straight shot into the bore. That's a discussion that has been hashed repeatedly here on the board and you'll have to decide for yourself what works best for you.

 

[Mike Bryant]

Pacific Tool & Gauge sells a cat head to take the place of the chuck. I bought one of them to fit a D1-4 spindle. You can buy a backing plate and make it yourself, but if your time is worth anything, it's simpler to get it from Pacific. It will hold a barrel well for indicating in a barrel, threading and chambering and is a help when you are dealing with long headstocks and shorter barrels as it will shorten the length through the headstock by about 3" depending upon how thick your chuck is. Pacific's cat head is all steel with large diameter aluminum tipped adjustment screws. It's $250.00. I'm not sure whether they make it for anything other than a D1-4 spindle. Pacific Cat Head

 

[skeetlee]

I have a brand new grizzly cathead for a d1-6 spindle if anyone needs one. ill sell it 70% of what it cost me. Lee

 

[MilGunsmith]

Cathead

I made a cathead for both D1-6 and Hardinge 4deg mounts. Use 1/2-20 thread setscrews with aluminium tips. They hold quite well and are easier to adjust than a 4-jaw.