https://precisionrifleblog.com/2020/04/28/bullet-jump-research-and-load-development-tips/Interesting read. If I understand it correctly, the article is basically suggesting that a longer bullet jump may not be as immediately accurate as a bullet length that kisses or jams, but will be more accurate throughout the life of the barrel because you're not having to forever chase eroding lands.
At least that is what I took from it. May have more potential significance for competitive shooters than the average shooter, dunno. I thought it was interesting that they were finding the best average accuracy with a jump that was relatively way out there.
It is an interesting article, but I don't think it's saying the rifle will be more accurate throughout the life of the barrel by staying in that 0.050-0.075" from the lands zone, but that the vertical will be more consistent at distance throughout that range.
It is an interesting article, but I don't think it's saying the rifle will be more accurate throughout the life of the barrel by staying in that 0.050-0.075" from the lands zone, but that the vertical will be more consistent at distance throughout that range.
That’s the way I took it but it’s been a few weeks since I read it. Certainly causes one to re-think chasing the lands for certain applications.
When this article first came up in "Ask The Gunwriters" a month or two ago, I mentioned that in my experience quite a few newer bullets and rifles shoot more accurately with bullets seated well of the lands. Not all, by any means, but quite a few--especially monolithic bullets and some of the newer high-BC lead-core hunting bullets.
Personally, I am quite happy that this article seems to indicate that my rifles and handloads that do this might remain consistently accurate longer--whether that means smaller groups at any range, or less vertical dispersion at longer ranges.
A lot depends on how your rifle is throated. In the article they are shooting precision rifles with tight throats. That helps with alignment.
Factory chamber throats can be ( but not always ) on the loose side. I find getting to the lands helps accuracy. Newer chamberings are spec’d with tight throats and are more jump tolerant. This helps accuracy all around and is why new chamberings tend to shoot really well.
Some rifle manufacturers are catching on and chambering their rifles with more attention to how tight the throat is.
Rifles with long tight throats are also less susceptible to eccentric ammunition. With less than .001” clearance , it’s hard to start a bullet really crooked.
Good accuracy smiths know all of this and subsequently spec their reamers for proper throat clearance. This is one critical aspect to getting older chamberings to shoot tiny groups.