Aye. Georgia Arms usually has good deals on bulk ammo. While I've not tried their .40 yet, I've run through plenty of their .45 and .223 without a single issue.
$17 for shipping for the 1k .40 in the OP. $9.80 tax Total: $166.80 ~$0.17 per round. I haven't shot any of their stuff before, though.
What does "These rounds were not intended for use in a polygonal style bore!!!!" mean? I know several pistol manufactures use polygonal bores.. What kind of ammo isn't intended for them and why?
They're lead rounds. Polygonal barrels don't like lead. You'll lead your barrel out fairly quickly running lead ammo through 'em.
Best deal I've seen on .223 is at Dicks, 5.98/20. Or at: http://www.ammo-connection.com/index.html $335/1000 (shipped)
The rifling twist is 1 in 15" in the .40 cal. and the fifling groves are 6. Don't know what that means in terms of a polygonal bore.
I doubt it. The only manufactures I know that use polygonal rifling are Hk, Glock, Kahr, and Magnum Research.
I couldn't find anything on it either. I do remember reading awhile back that the GSR didn't have the same type of barrel as the other Sig models and it isn't Polygonal.
Source: http://www.streetpro.com/usp/uspfaq.html Now, this source may or may not be accurate - but it looks like you Sig guys would be good to go using lead bullets!