303 British Neck Runout.....AARGH!!!

[Zeke Menuar]

Got moved, got my bench set up. Polished a few cases in the tumbler. I can use my noisy diesel powered case tumbler now, I have an honest to goodness garage.

Started with 303 British. Ran a couple of cases through a Redding neck sizer sans expander ball. Runout was .008 on both cases. Not real good.

Ran two more through with the expander ball. Same results. I am used to getting less than .003 with 270, 308, 8mm Mauser and the rest of the rounds I load for. This isn't right. Check the press. Make sure I am using the right expander ball. Use a small amount of lube on the outside and inside of the neck. Shellholder is free floated in the press. Still no change.

Tried a couple using the Redding FL die. Two with expander, two without. Wow an improvement! .005. Hmmm Still not good enough.

Broke out the 30 cal Hornady generic neck sizer. Tried two with expander, two without. Same results, none less than .005. Am running out of neck sizer dies.

Last resort. Out comes the RCBS 308 Winchester neck sizer. Two cases with expander .005 high, .002 low. Now I'm getting somewhere. Remove expander. Run five cases through. High .003, low less than .001. Right in the ballpark. Glad I'm using boat-tails or this could get ugly.

Not sure why this is happening. In addition to using the 308 neck sizer in 308. I use it for neck sizing 30-06 and now 303 Brit.

Wish I knew what was going on.

ZM

 

[Sunray]

"...Runout..." Can you define that?

 

[Zeke Menuar]

I use a RCBS Casemaster setup like this one :http://www.rcbs.com/default.asp?menu=1&s1=4&s2=3&s3=29 To see if the neck is crooked after resizing. Runout is the measurement of how crooked the neck is.

ZM

 

[Gewehr98]

Wouldn't a .308 Winchester neck sizer be a smidgen tight...

For the .303 British? (ie, .308" bullet diameter vs. .311" bullet diameter)

 

[Zeke Menuar]

For the .303 British? (ie, .308" bullet diameter vs. .311" bullet diameter)

Yep.

This is the second time I have had to try this with the 303. The aforementioned Redding and Hornady dies give lousy runout. The results are nice 6-10" groups from my No1MkIII. Using the 308 RCBS neck sizer(no expander ball) shrinks the groups to an acceptable 2-3". Doesn't matter if I use S&B or Winchester brass the results are the same.

The Hornady generic 30 cal neck sizer gives outstanding results when neck-sizing 300 Savage brass. Not so good on 303 brass.

Not sure why this is going on. I am thinking about sending the dies back to Redding for them to look at.

ZM

 

[Clark]

I am down on expander balls, ever since the day my concentricity gauge arrived.
My groups shrank.
Now my expander balls AND my concentricity gauge gather dust.

Save money.
Skip the concentricity gauge and just throw out the expander balls.

 

[Gewehr98]

Wow!

If you're resizing your necks down to the dimensions of a .308 Winchester's, and then seating your .311" .303 British bullets, you've the neck tension set pretty darned tight. I'd wager the bullet is acting as an expander ball in it's own right upon seating. You certainly don't want to swage the bullet undersized, so that leaves the case neck to bump up to nominal for the cartridge either on bullet seating or upon firing.