watkibe
03-29-2011, 11:48 PM
For ever, it seems like, I have been shooting Lee's 309-150-GC over SR4759 from my .308 Remington 788 with complete happiness and satisfaction. Always the same: water dropped WW, LLA before and after a trip through the Lee sizer, where the Hornady GC is installed.
Some time back, I got the mold for this bullet's big brother: 309-180-GC. Last time I loaded it up (using the same method developed earlier, except with slightly less 4759) I had a near-epiphany of delight over the accuracy and velocities. All was well.
Today I started loading a batch. I had clean, primed, flared cases ready. I dropped powder, inserted the boolit and seated it, moved it over to the Lee crimp die, and the first 8 rounds were very nice. Rounds 9 and 10 weren't very nice at all. The necks were obviously bulging unattractively. I knew they wouldn't chamber, but just for fun, I got the 788 and confirmed the sad truth : these 2 rounds would not chamber.
I re-checked the die settings, pulled the bullets, tried reassembling the rounds, checked case lengths; nothing made sense until I started to measure all my boolits. About half measured 0.310 on the forward band. The rest measured larger, from 0.312 on up to 0.320. I loaded up all 20 of the 0.310 group without a hitch, bobble, or unattractive bulge to be seen anywhere, and even better, they all chambered perfectly.
The puzzlement is this: How did all these boolits go through the same LLA, Lee 0.309 sizing die, pick up a GC, back through the LLA, and have such different diameters ?
I understand that all measurements have some small variation, eg. my 0.310 boolits coming out of my 0.309 die, no worries. These variations today though, are large enough to prevent chambering rounds, which is not a no-worry-be-happy situation. Due to viewer discretion issues, I did not photograph the graphic nature of the offending fatties.
Perhaps some of my elders here have some wisdom to shed on this can of worms.
Some time back, I got the mold for this bullet's big brother: 309-180-GC. Last time I loaded it up (using the same method developed earlier, except with slightly less 4759) I had a near-epiphany of delight over the accuracy and velocities. All was well.
Today I started loading a batch. I had clean, primed, flared cases ready. I dropped powder, inserted the boolit and seated it, moved it over to the Lee crimp die, and the first 8 rounds were very nice. Rounds 9 and 10 weren't very nice at all. The necks were obviously bulging unattractively. I knew they wouldn't chamber, but just for fun, I got the 788 and confirmed the sad truth : these 2 rounds would not chamber.
I re-checked the die settings, pulled the bullets, tried reassembling the rounds, checked case lengths; nothing made sense until I started to measure all my boolits. About half measured 0.310 on the forward band. The rest measured larger, from 0.312 on up to 0.320. I loaded up all 20 of the 0.310 group without a hitch, bobble, or unattractive bulge to be seen anywhere, and even better, they all chambered perfectly.
The puzzlement is this: How did all these boolits go through the same LLA, Lee 0.309 sizing die, pick up a GC, back through the LLA, and have such different diameters ?
I understand that all measurements have some small variation, eg. my 0.310 boolits coming out of my 0.309 die, no worries. These variations today though, are large enough to prevent chambering rounds, which is not a no-worry-be-happy situation. Due to viewer discretion issues, I did not photograph the graphic nature of the offending fatties.
Perhaps some of my elders here have some wisdom to shed on this can of worms.