Reloading die problem????????????

[Sagebrush Burns]

Lately I shot my 204 (Savage M12 LRPV) on paper and over the chronograph for the first time in a while and got an unpleasant surprise. My load (Berger 35 HP, 27.0 H335, CCI450, Winchester brass) which shot 3/8" 5 shot groups when I worked it up was now shooting 1 1/4" groups with velocity extreme spread approaching 300 fps. Very disappointing! I had developed the load using RCBS dies which showed large run out. In an effort to reduce run out and improve a good thing I got a set of Redding dies including a bushing neck sizing die and micrometer seating die. My loaded rounds measure .226 outside neck diameter so I got a .224 bushing so I wouldn't need to use the expander button and could reduce working the brass. After getting the large groups and velocity spreads I did some comparison testing using both sets of dies. Results were: Redding dies without expander button - 1 1/4" groups, 288 fps extreme spread; Redding dies with expander button - 7/8" groups, 190 fps extreme spread; RCBS dies - 1/2" groups, 50 fps extreme spread. Next I did some measuring of necks. The Redding .224 neck die sizes to a measured .222. Both RCBS and Redding expander buttons result in a neck measurement of .224. I'm trying to figure out where I need to go with this and how to solve my problem. I'll give Redding a call next week (they are closed right now for hunting season and Thanksgiving) but any ideas anyone cares to share would be welcome.

[Wrangler John]

If the RCBS dies produce loads that shoot .375" groups with x amount of runout, is there a problem?

Is the RCBS a full length or neck size die? Some rifles will shoot better with full length sized brass than neck sized only.

Does the runout appear in new unfired brass prior to sizing in the RCBS die? (Is new brass the problem - it can't be straightened if it's too far out.) Or is it due to neck thickness variation? What does neck thickness mike at various places around the neck? Try another brand of brass - Nosler or Hornady.

Does the runout appear in new brass sized and loaded in the RCBS die before firing? (Is the runout from the loading dies or is it being picked up by firing in a concentric chamber?)

Did you set up the Redding die with proper clearance on the bushing to allow it to float? Did you clean the preservative oil from the the bushing chamber first? Are you lubing necks slightly for the non-nitride coated bushings?

Did you try tighter bushings, say .221" or .220"? The Redding die should leave the sized neck the same OD as the RCBS after sizing. Take the RCBS expander stem out and resize a case without expanding, mike the neck, that will give you an idea. Try matching that result with a similar sized bushing in the Redding die with the Redding expander installed.

Remember the expander button irons the INSIDE of the neck to a uniform diameter, if the neck thickness varies then it doesn't hold the bullet consistently without excessive sizing and expansion. That's why the factory dies reduce the diameter beyond what is needed and expand it with a pull button, so the INSIDE of the neck is consistent.

Having adjustable bushings allows you to set neck tension for best accuracy.

Did you resize the RCBS sized brass in the Redding die? (The Redding die won't resize the case body unless it's a full length bushing die. Resizing brass won't always correct brass distortion, and any neck/shoulder misalignment will never be corrected in a floating bushing die.)

What happens if you size new brass in the RCBS sizer and seat the bullet in the Redding die? (This will ID the actual die causing the runout - could be the seating set up, lack of proper chamfer, bullet tilting etc.)

Good Luck.

[Sagebrush Burns]

Wrangler John -
Thanks for your reply - many good insights there...

"Did you try tighter bushings, say .221" or .220"? The Redding die should leave the sized neck the same OD as the RCBS after sizing. Take the RCBS expander stem out and resize a case without expanding, mike the neck, that will give you an idea. Try matching that result with a similar sized bushing in the Redding die with the Redding expander installed.

Remember the expander button irons the INSIDE of the neck to a uniform diameter, if the neck thickness varies then it doesn't hold the bullet consistently without excessive sizing and expansion. That's why the factory dies reduce the diameter beyond what is needed and expand it with a pull button, so the INSIDE of the neck is consistent."

I've been thinking I was dealing with a neck tension issue and had not considered it in quite that light. Sounds like my next step should be to try a tighter bushing with the expander... I have not turned necks on my brass; variation seems to run .001 - .002 which does not seem excessive to me. Perhaps, however, enough when combined with less neck sizing to cause my problem.

"If the RCBS dies produce loads that shoot .375" groups with x amount of runout, is there a problem?"

That isn't really a "problem", but it seemed if if the load was that accurate with a fair amount of run out, it could be even better if I could reduce the run out. Perhaps I should have stayed with the thought that if it ain't broke, don't fix it...

[Wrangler John]

What you are trying to do is match or better the performance of the RCBS loaded ammo with the Redding die set, in hopes of improving the ammo. First step is to duplicate the environment of the RCBS dies in the Redding, then if it doesn't shoot as well you can look at other factors; neck sizing depth, body sizing, etc. I use a Redding full length bushing die and adjust it so that a caliper set for the fired shoulder diameter just slides down the resized case about 3/8" to ensure easy chambering. Some rifles like that and some do just as well with neck sized only. My precision barreled rifles, with custom chambering prefer the neck sized only brass, while the standard chambers seem to like a little more sizing.

If the bullet seats below the neck, there may also be a donut at the base of the neck cocking the bullet off. This can be inside reamed on a fired case but I haven't looked for a .204 reamer. The best way is to use a ream die, but again I haven't seen if anyone makes one for .204 Ruger.

Also look for a sliver of copper jacket material after seating the bullet - this means the bullet is being skived by the neck. Increase chamfering or try a VLD chamfering tool. Too much neck tension will also cause it, but a sleeved seating die usually aligns everything well enough to avoid the problem.

I measured the neck thickness variation of Hornady brass - it's all I have - and it measures less than .001", usually .0005" to .0007". That is not worth turning. I do remove the wire ring from new factory brass where the trimmer raised a ridge. If you look closely at new brass, there is a ridge you can feel with your finger at the case mouth. The chamfering tool may not remove it, so I use a neck turning tool to just clean up the mouth.

Anything shooting .5" and below are all I need for ground squirrels, and I quit while I'm ahead if I better that. I'd rather shoot than load, and my frustration tolerance is very low these days.

[Sagebrush Burns]

Wrangler John - thanks again for sharing your experiences. I'm running some more experiments with a tighter neck bushing and checking against RCBS loads as a base line. Also got my hands on a (non-bushing) neck sizing die and checking that out too. I did clean the bushing die and found the bushing wasn't moving freely and got that corrected. I hear you about rather shoot than load but I must admit the process is interesting and I get a kick out of solving a problem ('course the issue is often figuring out the problem in the first place...)