What's the name and purpose of this design?

[kamelryttarn]

Please forgive me for posting this as I am sure it's been discussed before but I can't find what this type of design is called and what it's purpose is. All i know is that it's for black powder guns.

http://www.lymanproducts.com/includes/img/lyman/bulletcasting/blackpowder/504617.jpg

I am looking for a way to make a light weight (180-200 grain) 44 Magnum bullet for long range silhouette shooting. the design with huuuge lube grooves will keep the weight down but still retain a bit of length. since i want it for full house magnum loads I would like to know if it's a good idea to make a similar shaped bullet with gas check and crimp groove.

[Bret4207]

IIRC that's called a Maxi Ball. I see no advantage to that design for "full house" long range loads. You need bearing length for alignment, an adequate lube capacity- but not so much the lube flies off in flight, a strong forward section to align as the boolit enters the forcing cone...I just don't see any advantage to the maxi design. Hollow pointing might help you. Take a good, accurate standard design and HP it to get the weight down. That also moves the CG rearward which is almost always a good thing for accuracy.

[excess650]

The maxi-ball is a modern muzzle loading bullet design. The base band is bore diameter or close, and the middle and top bands are slightly larger to allow it to be thumb started and slightly engraved. The grooves are meant to be fill with lube to soften blackpowder fouling, and prevent the bullet from completely collapsing. These do work as designed, but won't in a high pressure, high velocity load.

[JIMinPHX]

That design of boolit is generally used with (low pressure) black powder loads. It's been my experience that hot .44mag loads will often collapse, slump, or deform a boolit that is not strong enough. You can see the results of my tests here - http://castboolits.gunloads.com/showthread.php?t=81258.

If you want to reduce the weight, have you thought about trying a big hollow point? A lot of target boolits use them these days.