crimped 308 bullet puller via milling chuck

[naejer]

Earlier today I decided to try for the first time to extract bullets from 4 non re-loaded (off the shelf) Winchester 308 rounds, crimped 147 gr FMJ bullets. I had 4 remaining bullets and was curious on their jump distance within my rifle, thus I needed to take one apart and perform measurements. If your curious on the method I employed check out quick video

 

[Dusty Stevens]

You could have just measured them with your ojive based comparator and compared that to a known length round

 

[naejer]

You could have just measured them with your ojive based comparator and compared that to a known length round

So far from my short exposure in reloading, the distances I measure from shell base to ogive varies pending the bullet brand,profile/length, etc.. ; however, the measurements are usually consistent to half a thou (0.0005) for same bullet model #. Unless I am missing something how can you establish jump without having previously carried out a chamber seating depth measurement, in my case with those OEM 147 FMJ bullets.
This was a first and last for me to take apart an OEM bullet, it was more of a curiosity to see powder weight discrepancies and the jump for these particular rounds which I only buy to gain access to Winchester reloading brass

 

[Dusty Stevens]

So far from my short exposure in reloading, the distances I measure from shell base to ogive varies pending the bullet brand,profile/length, etc.. ; however, the measurements are usually consistent to half a thou (0.0005) for same bullet model #. Unless I am missing something how can you establish jump without having previously carried out a chamber seating depth measurement, in my case with those OEM 147 FMJ bullets.
This was a first and last for me to take apart an OEM bullet, it was more of a curiosity to see powder weight discrepancies and the jump for these particular rounds which I only buy to gain access to Winchester reloading brass

Lets just say your comparator has a hole in it that is around the freebore diameter and you measure a round that you know has .010 jump- that same comparator diameter will give you a reference on another round close to what youre needing. The bullet in front of and behind that datum matters none with its shape because you are measuring that same point where that diameter would hit

 

[naejer]

Thanks for the feedback Dusty much appreciated. I had no other 30 cal bullets with same profile & weight to carry out your approach.

I manufacture mill/turn my own gauges and if I recall my 308 bullet comparator is bored out at 0.300 and thus pending bullet profiles (tangent, secant, length) after bullet’s ogive datum line (0.308) will indeed give you varied readings between the spectrum of bullets available in the same cal.

For example, my chamber’s max comparator seating with 155 Hornady A-MAX re-loads is 2.171” and I jump them at .006 away.

These OEM Winchester 147 FMJ resulted in a max comparator reading 2.196” that minus prior cartridge take down comparator reading of 2.184 resulted in now knowing that these were jumping at 0.012

And as Paul Harvey would say “And now you know -- the rest of the story”


LoL