Do you always need a rougher reamer or can you use a finish reamer to reamer a chamber on a new barrel? Thanks.

If you’re just going to chamber a couple of barrels you can get away with just using a finishing reamer. It’s just very important to have a finishing reamer as sharp as possible and the more material that you have to remove with it the faster it will dull.

I use a 600 grit paste to final polish a finish cut chamber. Is there any advantage to using a finer paste, say 1000???

Scott - I don't own a rougher for any of the 30 odd calibers I chamber for but, I don't chamber a lot of any particular cartridge. Unless I were doing a lot of chambering, I would rather send the finisher back for re-sharpening than sink the bucks into a rougher. If you are concerned with reamer wear, use a drill slightly under the chamber size and "rough" it that way.
Lowrider 49 - I don't use anything finer than 320 grit aloxite to polish a chamber. As long as the chamber doesn't leave any marks on a re-sized case it's actually advantageous to have the chamber a little "rough". Fred Barnes once re-chambered a .375 H&H to .375 Barnes Supreme for me and "polished" with 80 grit. I was very surprised and asked him why he didn't go finer and he said "they need to grip the chamber walls at ignition". I never had any cases that looked bad after firing and re-sizing. Re-sizing is when any real flaws in the chamber will show up vividly.

If the chamber is too smooth you could have extraction problems. I drill, bore with a carbide boring bar, and finish ream. It saves my reamer, has a straighter hole, and saves time.
Butch

quote:

Originally posted by butchlambert:
I drill, bore with a carbide boring bar, and finish ream. It saves my reamer, has a straighter hole, and saves time.
Butch

Same here. It's fast, efficient and very precise, not to mention, it saves money!

Could you be more explicit. Do you drill to just short of the shoulder and then bore the correct taper with the compound? Also does the pilot of the reamer enter the bore before the reamer starts to cut?

Thanks, Hart

quote:

Originally posted by hart:
Could you be more explicit. Do you drill to just short of the shoulder and then bore the correct taper with the compound? Also does the pilot of the reamer enter the bore before the reamer starts to cut?

Thanks, Hart

Run the drill in until you are about .050 from where the shoulder will be. Then bore the hole to about .005 under what the finished shoulder diameter will be, again holding short of the final depth. The reamer will begin cutting before the pilot is in the bore. If you are using a quality barrel and everything is set up correctly and running true, then the reamer will guide itself.

People place too much emphasis on the pilot. The only time I can see the pilot as being useful is when rechambering factory barrels, or, working with any barrel with a less than straight bore.

I've reamed several barrels with only a finishing reamer.....since I don't use a reamer more than a few times it's not a problem.

Listen to Mr. Malmborg. Even if I weren't trying to save a reamer, I want to save time and have the reamer follow a straight hole.
Butch

Will I need to use a throater, or will the chamber reamer knock some of the lands down a bit so I dont have a short throat?

Scott I would order a reamer with the throat that I wanted. You can order a throater and use it for different bullets and seating depths.
Butch

Thanks guys! You made very good points.

I cut a 336 Marlin .30-30 AI chamber last night and used 320 grit to get a cross hatch "cylinder hone" pattern. I fired 20 rounds to fire form tonight and got what I think are perfect AI cases. No problems with extraction and they resized (just short of the shoulder) with no problems. That was a very easy conversion...can't wait to see if it will shoot well....and what it does on the chrony.