1100 rpm? Is that an Ingram or a 1911 with some sear trouble? Well, I have reloaded both for a lucky friend who has a couple of SMGs in 9x19 and 45 ACP, and the jacketed bullets are much more reliable. We did not have problems with leading in the barrel, but the lead bullets are much dirtier and leave deposits and shavings in the chamber, only good for a few mags, then you have to clean. You should not use lead bullets in HK MP5s and similarly polygon rifled guns. Also if your SMG fires from an open bolt you could detonate an unsoported, partially chambered round, bad news!!