Best 30-40 dies for match grade loads

[Keith Herrington]

I'm now down to my last 50 rounds of loaded 30-40 ammo with my 500 new cases. Got the 450 once fired cases cleaned and am in the process of brushing the inside of the necks, cleaning the primer pockets and deburring the flash hole.

I've tested my dies with 10 culled pieces of brass and am getting way, way, way too much run-out on the resized cases. My dies are a 2-die Redding set, #80147, which includes a FL resizing die with neck expander and a seating die. I use a Lee Factory Crimp Die to finish off the cartridge.

I've disassembled the FL sizing die and polished the neck expander button for a smoother transition, but the best runout I can achieve is .007" to .008" runout. I am at a loss to know what else I can do to make the brass more concentric.

Any ideas?

Would RCBS dies be better?

[reincarnated]

Have you tried your loads on paper? They may be good enough. What is the runout on loads of known accuracy?

I have found the tolerances on Redding dies to be tighter than RCBS. Redding does sell some sort of "micrometer" dies for producing match ammunition, in .30 cal but not 30-40. Maybe a phone call to Redding will solve the problem.

The other alternatives I suggest are switching to a Vickermann-type bullet seater. If that does not work, investigate Wilson dies. They use an arbor press.

[cdagnese]

Might also stop using the Lee crimping die. It's not needed. Also take a close look at your seating die and check the diameter of the neck expanding button in two places 90 degrees apart.

[Keith Herrington]

I've tested my dies with 10 culled pieces of brass and am getting way, way, way too much run-out on the resized cases. I've disassembled the FL sizing die and polished the neck expander button for a smoother transition, but the best runout I can achieve is .007" to .008" runout.

To reiterate, I'm measuring runout on the resized cases, not the assembled rounds. Normally, I want my resized case runout to not exceed .002"-.003" in order to keep the loaded round runout below .005".

[reincarnated]

Maybe it's not your dies. I have a Bannerman (?) Krag with the chamber not 100 % in line with the bore.

[Keith Herrington]

Maybe it's not your dies. I have a Bannerman (?) Krag with the chamber not 100 % in line with the bore.

I had the same suspicion so I took several fired cases and measured their runout...all were .002" or less. Not bad for once fired commercial brass. My next suspicion was the neck expander button so I removed it from the die just now and sized 6 cases. The runout didn't increase...all measured less than .002". However, the neck was over sized by .009". I wanted .333" to give myself .002" of neck tension but the necks all measured .324"-.325". So, my distortion is coming from the expander button having to expand the neck almost .010", way too much. I've ordered a few die sets (RCBS, Hornady, etc.) and will try them as well. I'll also reach out to a bench rest buddy of mine to see if he can increase the size of the neck by .009".

More to come.

[reincarnated]

My thoughts are that the Redding FL die is reducing your neck diameter too much. That will lead to more unnecessary case trimming and will eventually shorten your case life.

There are such things as neck sizing dies. If you only have one 30-40, that may be the way to go. Also, you might try a FL or neck die for .303 British. Those are probably easier to find than a 30-40 die.

[FredC]

I do not like over working the brass either. On a die like that I might try lapping it with a shop built adjustable lap. If you lap .006 to .007 out of it you might take all the chamfer or radius out in the transition from the shoulder to the neck. A piece brass with a 45 degree angle applied to that transition with the same lapping compound would fix that.

Another thought on the runout, if the neck OD and ID are not concentric the difference in thickness may be causing the expander button to shift when pulling out.
Also the adjustable rod the expander button is mounted on may be bent. Is the runout always in the same direction? Does it get better if the expander lock nut is loose?

[madsenshooter]

I've experimented a bit with using a 7.5x55 Lee collet neck sizing die with a 1/16 washer under it to size just a bit over half the neck for slow fire rounds. (Collet die for 30-40 would be special order). It did tighten the group up a tad. I also try to cull cases that I can see haven't expanded equally back near the head, you know a bit more bulge on one side.

[Keith Herrington]

I've been on the phone and on line with a variety of die makers. Here are the results:
a. RCBS and Redding are too busy to make a custom sizing die. However, Redding has a collet neck sizing die for the 30-40, number 77147 that you can order from Graf and Son and other Redding distributors.
b. Forster has the ability to assemble competition seating dies but not sizing dies.
c. Hornady will make a custom set of dies. All you need to is provide them with 5 pieces of fired brass. Contact Ben Syring, Engineering/Reloading Die Design, Hornady Mfg. Co., 3625 W. Old Potash Hwy, Grand Island, NE 68803 or call him at 800-338-3220.
d. Whidden Gunworks will also make a custom die set. I've used Whidden in the past and liked their product. I'm sending them five (5) cases today along with 5 of the 220 Hornady RN bullets I use. I'll let you know what I find out.