Good morning TFL! I was at the loading bench last night finishing up what 7mm mag brass I had shot recently. The bullet I'm using is the 162gr ELD-X. I've been through about 300 or so of them, and my rifle really seems to like them. I DO use a hornady comparator to measure seating depth when loading, and I check every round. Last night I finished one box of bullets and opened up another (different lot numbers). The comparator measurement was so far off, that I need second opinions here. Pictures included.
CBTO on the first box (we'll call that box A) was 2.707. This is what I developed the load with, and is .035" off the lands.
CBTO on the next box (we'll call that box B) was 2.740. That's quite a large jump.
Initially, I thought maybe my seating stem had backed itself out somehow, but everything was tight. That led me to checking the bullets out in a little bit more detail. None of these are factory seconds. I generally do not measure every bullet prior to use (though that might be changing shortly), and that's mostly worked for me over the past 17 years or so. Anyway, the bullets out of box B were significantly fatter and less tapered than the bullets out of box A (see pictures). Enough to change where the comparator measures the ogive .033". Now, in my rifle that's still not touching the lands, but that could be real issues with folks who load these babies close to the rifling.
Onto accuracy, obviously this is going to affect accuracy, but the question is how much. I find it hard to believe that the BC between the two bullets are very close at all. I loaded up 3 rounds, and I'll test fire them and report back with the changes. I THINK what I'm going to do, let me know if you agree, is back the powder charge down .5-1.0 gr and do some fine tuning of the load with the bullets seated back at .035" off the lands. I hate to say it, but I'm starting to develop trust issues with hornady bullets! That brings me to my next concern... if this happens continuously, and you have a match coming up, or a big hunt coming up, you better factor in significantly more time to load your ammo if you're going to have to retune the load everytime your lot number changes. It kind of sucks that long gone are the days of reloading your secret recipe in bulk.
EDIT: I'll get some BTO, length, and possibly bearing surface measurements for the bullets if anyone cares about that! I'll pull one of the old bullets tonight as well, so we can compare. FWIW, the OAL was the exact same
CBTO on the first box (we'll call that box A) was 2.707. This is what I developed the load with, and is .035" off the lands.
CBTO on the next box (we'll call that box B) was 2.740. That's quite a large jump.
Initially, I thought maybe my seating stem had backed itself out somehow, but everything was tight. That led me to checking the bullets out in a little bit more detail. None of these are factory seconds. I generally do not measure every bullet prior to use (though that might be changing shortly), and that's mostly worked for me over the past 17 years or so. Anyway, the bullets out of box B were significantly fatter and less tapered than the bullets out of box A (see pictures). Enough to change where the comparator measures the ogive .033". Now, in my rifle that's still not touching the lands, but that could be real issues with folks who load these babies close to the rifling.
Onto accuracy, obviously this is going to affect accuracy, but the question is how much. I find it hard to believe that the BC between the two bullets are very close at all. I loaded up 3 rounds, and I'll test fire them and report back with the changes. I THINK what I'm going to do, let me know if you agree, is back the powder charge down .5-1.0 gr and do some fine tuning of the load with the bullets seated back at .035" off the lands. I hate to say it, but I'm starting to develop trust issues with hornady bullets! That brings me to my next concern... if this happens continuously, and you have a match coming up, or a big hunt coming up, you better factor in significantly more time to load your ammo if you're going to have to retune the load everytime your lot number changes. It kind of sucks that long gone are the days of reloading your secret recipe in bulk.
EDIT: I'll get some BTO, length, and possibly bearing surface measurements for the bullets if anyone cares about that! I'll pull one of the old bullets tonight as well, so we can compare. FWIW, the OAL was the exact same
