Please bear with me, I have only been reloading a few weeks. Love the technicality of it all, but am confused by the discussions of Bullet Jump.
Where I can't get to grips with it is that I read people saying that .020 of Bullet Jump is best, some say even down to zero bullet jump. Some say certain bullets need a longer Jump. Folks talk about adjusting the Jump up or down by .005, and so on.
However, if you look at the reloading tables in, say, the Lyman 48th. The COAL for different weight bullets may be different by up to 1/4 inch.
So, if I use one of the lighter bullets, and the recommended COAL for that bullet, am I not introducing a bullet jump change of an extra 250 thou? How can that be right when people are talking about 20 thou or less?
If I seat a lighter bullet anywhere near the COAL for a heavier bullet, then it's hardly in the neck and obviously unusable, so that's not an alternative.
I had found by trying different load recipes that my rifle "appeared" to prefer a heavier bullet. Now I'm wondering if it just prefers a longer bullet giving shorter Bullet Jump. Maybe I need to find a long, light bullet to try?
It almost seems to me that if you use a shorter bullet, you should case trim to a longer length, so you could have a consistant bullet seating, and a consistant Bullet Jump. That's to say having different length brass to suit differing length bullets (whether to the tip or the ogive, whichever). However, this is not the case, so I'm missing the point somewhere.
See what I mean? If my case TTL is 2.212, and that gives me optimal seating and Jump for a 180 Gr bullet; if I want to use a 20 thou shorter 125 Gr bullet, wouldn't using a case TTL of 2.232 give me identical seating and Jump? Like I say, I must be missing something, otherwise why is this not what one does?
OK, enough drivel, I hope I've explained my dilemma. I'd appreciate the views of those with far more reloading experience.
Cheers, all,
gravityfan