After more than 30 years of loading ammo of various calibers and guages, I am having some trouble with a couple of my rifles that I previously had not trouble. I am pulling at straws now. I , at first tried to neck size the fired cases with a Lee collet die which resulted in very poor neck tension. Bullets would spin in the cases. Is this a bad collet die????? I then completely disassembled the loads and full length sized them using a Redding full length die. Am I forgetting something? The neck tension is back up but accuracy is no bueno.
This is what I have to work with.
WW 7mm Mauser brass that I blue print.
Fed 210M primers
a variety of bullets to try.
Where would you suggest to start. I need a proven accurate load for 7x57 and a twist rate
of 1;9.5/1:10. At one time the rifle shot 139gr hornady and the 160gr Nosler Partition bullets well, under an inch. Not now. I think the bedding might need tweaking. The thing that is worrying me is that the 160 gr. load that worked so well here and in Africa, suddenly has developed pressure problems. To the point of popping some primers. Now that may be because some of the brass loaded 6-7 years ago might have been loaded too many times and now is giving up. I frankly do not know what to do at this point.

What is the proper way to set up a full length sizer?

quote:

square shooter

To set up for full length resizing:
1.Move the ram (with the shell holder in place) all the way to the top of the stroke!
2.Screw the FL resizing die in until it makes contact with the shell holder!
3.Lower the ram and screw the die in about 1/4 turn!

Now, when you push the press handle all the way down, you will get what is referred to as "cam-over"! This is what's needed for FL resizing!

To set up for partial resizing:
This mostly resizes the neck, but does resize the rest of the case a little too!

1.Move the ram all the way to the top of the stroke!
2.Screw the FL resizing die in until it is about the thickness of a nickel from touching the shell holder! This setup will mostly resize the neck only!

I hope this helps you out!
Good luck!

Thanks, that is what I do and I have very good equipment. Still having trouble with a couple of rifles that won't shoot.

I can almost guarantee that your sizing die isn't the problem. If a gun has been known to like a load and it's now not shooting something has happened.......here are some things I would check and I'm sorry if I sound silly with the basics.....

1. perhaps reloading components have changed....lots of powder seem to be getting hotter....if at all possible compare with a chrono if you have switched powders.

2. Screws loose on gun action, scopes etc. Is the scope for sure ok?

3. Extreme copper fouling in barrel. Get it out with sweets or wipeout.

4. Crown damage. Bedding issue.

Re the lee collet die. It sounds like you have to sand down the spindle that the collet presses against. I've got about 5 of the dies and none have left the case mouth as loose as you have.

Also...some people seem to think that sizing your brass so it leaves just a slight amount of bolt tension when chambering is a good idea. THIS HAS NEVER WORKED FOR ME. I would recomend sizing so that your bolt closes as easy as any factory loaded ammo....this should certainly be what you want when you are in the field hunting anyhowl.

Adjusting the FL Die to Partial Full Length Resize is a bit more involved than just setting the Die with about a nickle's thickness space.
Here is a link to Hot Core's expaination on PFL.
https://forums.accuratereloading.com/eve/forums/a/tpc/f/...=639101932#639101932

quote:

To set up for full length resizing:
1.Move the ram (with the shell holder in place) all the way to the top of the stroke!
2.Screw the FL resizing die in until it makes contact with the shell holder!
3.Lower the ram and screw the die in about 1/4 turn!

I did this with a Lee die (7.62x39) and it undersized the case about .020.

I discovered this after several round would not fire. I first blamed it on the firing pin spring which was weak.

I replaced it and those rounds would fire.

However, when checking the case from the casehead to the "datum" line and comparing with a factory case, I discovered problem #2, too short of a case. Replaced the Lee with a RCBS and rechecked.

Perfect.

Things are not always as you would expect.

On partial resizing, i mark the neck with a black marker and adjust the die till the die removes the black just up to the shoulder. then chamber the case to make sure it fits.

FWIW--Re die set up I have the stoney point headspace bushing kit. I think they are about $35. I do alot of reloading for alot of guns. I could not reload without it. I think it's a must have for any avid reloader.....once you've had it I'll bet you'll agree.

I think Kraky is on the right track. Components do change over time and a load that was near max could now be over.

The collet die needs to be set up as directed in the manufactures instructions. The die will break if screwed in too deep (don`t ask how I know but 2 sets of dies have convinced me of this) and won`t size the necks any tighter. You can turn the case 90* and restrike them for a little more tension and Lee recommends polishing ~0.001" of the spindle to add tension if needed. This won`t add any more tension if you over do it, 0.002" won`t help.
I haven`t had any trouble after I first learned to set my collet dies up. The only exception is some real thin brands of cases don`t size quite as well as thicker. The ones I had trouble with being too thin were as I remember some 6.5x55 S&B stuff. They worked, but tension could have been better and I went to my regular RCBS FL die when useing them.

kraky nailed it with the Stoney Point Headspace, one of my most used tools.

Quoting from the Lee Collet Die instruction sheet:

"ADJUSTMENT FOR LEE PRESSES
Screw the sizing die in until it contacts the shell holder, plus one turn more. Run a case into the die. You will feel the primer being extracted, then the lever will come to an abrupt stop. At this point, the lever must be pushed firmly (min. 25 lbs.) to close the collet and size the neck. Extra bullet grip can be obtained by screwing the die in an additional quarter-turn.

Other brands of presses that toggle or snap over center at the end of the stroke provide no feel and can damage the collet neck sizing die if adjusted as above. We suggest the die be screwed in until the die contacts the shell holder, plus 2 FULL TURNS. This will prevent the press from toggling over center and give the operator feel of the collet closing.

OPTION
Even greater accuracy can be obtained by rotating the case on-half turn and sizing the case a second time."

When sizing with the collet, I adjust the die in until the press lever is only about 1/2 way down or sticking as straight out horizontal to the floor (usually about 3 turns in). Then I estimate about 25 to 50 pounds of my weight down on the lever. It is never supposed to go all the way down and cam over nor are you ever supposed to close the collets without a case in it.

I own a dozen collet dies in different calibers and none of them leave the neck with insufficient neck tension.