Lube Groove Design?

[Whitespider]

I’m still learnin’. I see from time to time, on these boards, comments about lube grooves. The consensus is that square bottom grooves are preferred over rounded, why is this?

[45nut]

Well,, round bottom groove designs cast easier, but ole' elmer was a proponent of the square bottom design. I think the idea was it would hold lube better.
With the nostalgia for true elmer mold's holding strong there will be people that swear by them.
Personally, I have no such preferences and with the superb lube's offered by Lar45,Bullshop and Felix's World Famous recipe available I do not feel undermined by the absence of the square bottom groove in my shooting.

[Bullshop]

Theory is that a square bottom groove will compress less and more slowly than round. This would allow the lube to be distrubited for the length of the barrel and if an adiquite supply will not run out. It was believed that a round bottom that compresses quickly would dump its lube too quickly and may not reach the muzzle. Some boolit designs are just better suited to high pressure than others. The Luverin is one of those. Even though it has round grooves it carries lots of lube and is lubricated for most of its length. The square bottom was preferd for the Keith design which had only one lube groove. Single lube groove designs are never my choice for high pressure loads especially in rifles. For hand guns with short barrels and with the super lubes available it seems not so important.
BIC/BS