Lee Resizing Die .308 - slightly off?

[bsumoba]

So I was in the process of resizing some 308 brass. I decapped them first with a universal, I lubed them, then pressed it.

Put the case in a case gauge check (JP 308/7.62) and the head from the maximum height section of the gauge is proud by about .001 or less. Will this be an issue? The brass comes in and out of the case smoothly and easily.

[Dutch Henry]

Try the case in the rifle and see if it will chamber and the bolt will lock fully. If not, you may need to adjust the die to setback the shoulder until the case head settles into the gauge. Sometimes it is trial and error until you get the right fit.

[ExtremeX]

What are you loading for? Bolt or Semi?

You really should use fire formed brass and a headspace comparator to set FL sizing die if you want to do it right. Sizing brass to your chamber is more important and better practice than sizing to a SAMMI case gauge. What you need is a comparative measurement between the fired formed brass and the sized brass.

For example in a bolt action… if .001 above the minimum step is acceptable if you have pushed the shoulders back .001 to .002…

If sizing .001 above the min. step on the case gage puts your shoulders back .005 to .006 it’s been sized too much.

Both will show the same results in a case gage, but those results are irrelevant since its not an accurate representation of your chamber.

[J-cat]

Check the sized case against your actual chamber, not some gauge. Did the same guy who made the gauge cut your chamber? No. So you can't rely on it. You are assuming all chambers are within spec and they are not. At best, most chambers are.

[bsumoba]

I am loading for a semi LR-308 build. I have a JP Supermatch barrel and the case gauge is also made by JP so theoretically, it is suppose to match up.

Check the sized case against your actual chamber, not some gauge. Did the same guy who made the gauge cut your chamber? No. So you can't rely on it. You are assuming all chambers are within spec and they are not. At best, most chambers are.

See above. Case gauge is made by same company supplying the barrel.

[ExtremeX]

I am loading for a semi LR-308 build. I have a JP Supermatch barrel and the case gauge is also made by JP so theoretically, it is suppose to match up.



See above. Case gauge is made by same company supplying the barrel.

Even if that is the case, my statement still holds true… I would want to use the least amount of sizing for your chamber… where that sits on your case gauge I don’t know… Probably as close to the maximum step as possible to get close to a zero headspace without causing feeding or reliability issues.

For my semi auto match rifle I am getting away with .0015 to .002 worth of sizing and have zero issues with feeding and reliability. Excellent case life and accuracy too.

[ExtremeX]

You are assuming all chambers are within spec and they are not. At best, most chambers are.

Out of the 8-9 different .223 rifles I have done comparative measurements on from fire formed brass to a fully resized case, only two were actually the same.

So I agree with you, until you actually mic out your own chamber with fired brass and take a measurement, you really don't know for sure.