Lubing a Lyman 457643

[Exousia]

I am a beginner and have started casting for my Marlin 45/70 using the Lyman 457630. I notice that this results in a boolit with 5 grooves. How many of the grooves are for lube? It looks like the second groove from the top is intended for the crimp. Should this groove be lubed? What about the top groove? Should it be lubed? The easy thing would be to lube all five grooves. I just don't know the proper lubing for this. I would appreciate some direction.

[peerlesscowboy]

Lube just the bottom three, crimp in the fourth and leave the top one clean.

[Exousia]

Thank you.
Do you know the purpose of the top groove?

[peerlesscowboy]

Thank you.
Do you know the purpose of the top groove?
I must admit.......I don't :oops: Maybe somebody'll chime in here that does :confused:
Good bullet BTW, I load 'em in my Browning '86 carbine. Seat 'em so the rear end of the lands engrave that narrow front band that's between the crimp groove and the ??? groove. Very accurate!

John C. Saubak

[BCall]

This was written by Dave Scoville in 2004 I think-

Around 1997 Ed Schmitt, the manager of product planning at Lyman at the time, and I designed a series of bullets for Lyman with grooved noses, to provide a relief groove for alloy that might be displaced by the lands when the nose of the bullet upsets and foreshortens. The series included the .22 245646, 6.5 268645, .270 280642, .30 311644 and a .45-caliber 457643. The .22-, .270-, .30- and .45-caliber bullets are listed with load data in the current Lyman 48th Edition Reloading Handbook, and I’m told 311644 is still a steady match winner.

It is copied from an article that is on Barnes Bullets site. I have heard numerous reasons from a scraper groove or extra lube for the nose on a bore rider boolit. This may just be another explanation., I don't truly know. I have lubed the nose of some of the other boolits in the series, the 225646 mainly, and can't say it improved anything. More of a hassle than anything.