Bullet Seating die and tolerances

slushee

slushee

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One more question :rolleyes:

So i just ran my .308win 168gr SMK HPBT's through a LEE Bullet Seating Die to 2.805" .. and I was getting up to +/- .005" .. is this normal?

That means that my rounds fluctuate between 2.800" and 2.810" OAL ... I was curious if this was good or bad?

Also, some of my rounds are between .001" - .002" undersized .. will it be okay to shoot these?

Thanks for all the help!!
 
Tagged for interest. I noticed this as well, but I figured it was simply slight differences in bullet length at the tip.
 
Get a Comparator, the measurement of the bullet from base to tip can vary. Measure a bunch from the box and you will probably find .010-.020 differences in the lengths.

A comparator measures from a set point on the ogive.
 
I just got back from the bench where I measured a few bullets to see a .010" spread in measurements .. so that's obviously where my tolerances are coming from.

So I suppose having that little bit of tolerances in OAL is okay? Is there a better way for getting OAL tighter or is this what everyone lives with?
 
When I make pistol ammo (.40 S&W) I get about the same variances. (1.120" to 1.130"). I use a digital caliper to measure and I have noticed that depending on how I rotate the cartridge in the caliper (basically where the arms of the caliper touch the bullet and base of the cartridge) I can get differences of .001" or .002". I'm not too concerned however since on average most of my ammo appears to be within 0.002". Its only the odd few that stray more than that. Up to now, I've never had a problem with OAL...but thats pistol ammo...Rifle ammo may require better tolerances, I dunno.
 
slushee said:
I just got back from the bench where I measured a few bullets to see a .010" spread in measurements .. so that's obviously where my tolerances are coming from.

So I suppose having that little bit of tolerances in OAL is okay? Is there a better way for getting OAL tighter or is this what everyone lives with?
Click to expand...

C-O-M-P-A-R-A-T-O-R to measure.

09-1000.jpg


Your seating die does not use the tip to seat, rather it uses a fixed spot on the ogive. You will find that if you measure with a comparator your seating depths will be almost identical. I find +/- .0005-.001 difference in the odd round.
 
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