ORIGINAL: stalkingbear
You're almost correct. The foster style slugs predated the excellent benneke slugs by a number of years. What benneke did was simply improve on the idea by screwing the bore fitting wad on bottom instead of using a seperate wad behind the slug,thereby offering a better weight foeward balance which resulted in better accuracy. The foster AND benneke slugs were designed to be safely fired thru ANY choke existing at the time of their introduction. The "ribs" on the side of slugs were NOT designed to compress,but rather in hopes of inducing somewhat of a stabilizing spin to the projectile in similar way to a smoothbore round of the some of the earlier tanks.
ORIGINAL: dog killer
WOW ! i posted this same question on 3 other sites as well and it seems there are a number
of hunters that are very uninformed [MYSELF INCLUDED] about this question. SO,i did some googling and found alot more of the same confusion !
i also found the answer....seems like BRENNEKE designed the rifled slug to be able to shoot through any choke. the ribs on a rifled slug provide space for the slug to compress as it passes through.
heres the link to the site
http://www.brennekeusa.com/web/text/faq.html
by the way....i shot some slugs through it today and no splintered barrel !
good group at 50 yds but they did drop about a foot and spread out some at 100 yds.
My understanding is that the Foster-type slugs were designed in the 1930's here in the U.S., and that Wilhelm Brenneke designed his in the 1890's in Germany for use there and in Africa. So I believe Brenneke was first with his "any choke's OK" slugs, rather than Foster. But I don't believe you could get Brennekes here in the U.S. at first. They were later imported, I believe, by Stoeger's. But I do not know when they actually were introiduced in the U.S. (Brennekes are great slugs, BTW!)