Yes. So were 300-grain bullets designed with rebated boattails so they'll fit in a .45ACP case. Their web site resolves elsewhere and a cursory check seems to indicate that Northwest Custom Projectiles is no longer around, but here's a link to a thread that discussed their 300-grain .45ACP bullets: http://forums.1911forum.com/showthread.php?t=142929" onclick="window.open(this.href);return false;surprise_i'm_armed wrote:Are 250 grain .45's available?
Over the years, I've reached the conclusion that if you ask "Does it exist?" about anything gun-related, if you do enough research you'll find some inventive type has already built it. We seem to attract tinkerers and inventors.