bore rider contact

[kokomokid]

I am curious as to the original design of the bore riding boolit? Was it suposed to lightly engage rifleing or maybe have agood interference fit? Or maybe slightly smaller than bore and bump up?

[doubs43]

I have a 500 grain 45 boolit that kind of polishes the sides of the nose on the tops of the lands. That seems about perfect to me.

[Southern Son]

My Creedmoore from Brookes is the same, if the fowling is bad, then it is more of a scraping than a polishing.

[405]

Original bore rider or origin of the concept?- That may depend on the definition. I'm sure that the concept has been experimented with for a long time- certainly in the 1800s and maybe earlier. I'm also fairly sure some of the early match/target shooters employed the bore rider concept. After all, breech seating is "bore riding" taken to the extreme in a cartridge gun. If you look CLOSELY at a 45 cal 500 gr Govt RN dating from about 1880-90, you'll see the nose has no real parallel sides for engaging the lands. It is somewhat tapered so that at best the widest part just in front of the front drive band/crimp groove may just touch the leade in a tight bore/shorter chamber. For battlefield/black powder fouling conditions a true bore rider could prevent chambering- not a good tactical condition. I've looked at some old original paper patched rounds where the papered portion of the bullet shank may engage the leade or lands in a tighter bore/shorter chamber- but the norm was a slightly undersized diameter that would not prevent chambering as the bore fouled from black powder.

Currently, I think the generic design of a "bore rider" has a relatively short shank for seating in the case neck... then a relatively long nose that does have a long parallel section that is very near bore size (land to land dia). That nose section ideally should just barely engrave the lands as the round is chambered. If one relies on "bump up" of an undersized nose to at least engrave into the lands or obturate into the grooves then only by chance will the bullet maintain concentricity as this obturation happens. I have NEVER found that to produce an accurate shooting combination. My thought is if that long nose with all that mass (inertia) is bumped to the side in a random manner each time.... the result is poor accuracy- which I see everytime I have tried to shoot a modern, conventional bore rider with an undersized nose.

[Larry Gibson]

405 nailed it.

Larry Gibson

[montana_charlie]

My thought is if that long nose with all that mass (inertia) is bumped to the side in a random manner each time.... the result is poor accuracy- which I see everytime I have tried to shoot a modern, conventional bore rider with an undersized nose.
Sounds right to me ...