I have neck sized about 40 rds with my Lee collet die ( 300 win) My groups are not as tight as Partiall Full length resizing with my RCBS dies. I want to make the Lee dies work but not at a sacrifice to accuracy. I think getting consistant neck tension is my problem. Should I ...
1) Get a smaller collet from Lee?

2) Get a crimp die from Lee and crimp?

3) Both of the above?

4) Just buy some good bench rest quality dies and keep going?

Thanks. Can't shoot until it cools off anyway. Summer is definiteky not all it is cracked up to be.

In regard to question number one ("smaller collet"), the question leads me to believe that you think your neck tension is insufficient. If that is the case, it is not a "smaller collet" you want, but there are two approaches.

First, as you withdraw your resized round from the die, rotate the case 45 degrees and size a second time. This will make the neck tension a bit greater and the neck theoretically a little rounder by pressing on the little ribs left where each of the four collet petals come together with one another.

Second, if this doesn't provide the neck tension you're looking for, remove the decapping mandrel from the die and chuck it in a drill. Spin it against very fine emory cloth to very slightly reduce its diameter by .001" inch or so. DON'T OVERDO IT! The reduced diameter of the mandrel will be reflected in the inside diameter of your resized cases. OR, you can order a smaller mandrel from Lee.

Forget crimping -- there's nothing "on purpose" it can do to improve accuracy. Sometimes it seems to do so totally by accident. BTW -- you'll never see benchrest shooter crimping their ammunition. Get the hint?

In the end, your chamber may be just a smidgeon out of alignment with the bore. If this is the case, then neck-sizing only leaves a somewhat misaligned cartridge in the chamber. Partial full length sizing tends to work better with some guns and chambers.

quote:

Originally posted by chain:
I think getting consistant neck tension is my problem.

If the problem is insufficient neck tension then reducing the diameter of the mandrel as described above should help.

If the problem is inconsistent neck tension the problem may be with your procedure. Collet dies require a little getting use to, and you need to be sure and apply the same amount of pressure on the press handle each time. You'll get a feel for it after awhile. Also, rotating the brass and running it through a 2nd time helps. If that doesn't work you should should look at your brass. If it has been reloaded several times it may need annealing; because of the way a collet die operates it doesn't work well with work-hardened brass.

quote:

Collet dies require a little getting use to, and you need to be sure and apply the same amount of pressure on the press handle each time.

Well said, belaw.

Despite Lee's warning NOT to set the dies so that the press "cams-over", I find that method works perfectly to get consistent collet pressure. The reason that Lee warns not to set the press up to cam-over (toggle past the Top Dead Center) position is to prevent the infinite leverage during the cam-over from damaging the base of the collet. The collet, like most of Lee's economical products, isn't made from the very hardest steel, and, if excessive pressure is placed on it by the shellholder, it will "brad" or "peen" until it is distorted and useless.

However, if your press allows it, you can tune the depth of the die in the press to place just the right pressure on the collet as it toggles over. With most compound leverage presses, the right amount of "squeeze" requires about -- and this is a wild guess -- 20-25 pounds of pressure on the press handle for it to toggle over. If you set it to require 50 or 60 pounds, then you will ruin your collet within 50 resizings.

Some presses have a stop that doesn't allow them to cam-over. If that is the case with your press, then you'll simply have to gauge the amount of handle pressure that works best by "feel".

My press does have a stop and it doesn't toggle over. I have spun the brass and worked the lever again. I have even tried to kind of measure the inside of the necks with my calipers. I probably don't have the touch or maybe my rifle just doesn't like the neck sizing as well as the partial resizing. Thanks