yodog...., When IMR 7383 first became available to reloaders, we knew little about it, except that there were 3 lots, which varied by "speed." It was also thought to be a triple based propellant. Shady Grady on the Boolits site citing military data (cutting & pasting in fact) showed that to be false. Buckshot and others suggested it was "peaky" and cautioned us to treat it akin to IMR 4064 as a starting point. Using a chronograph, I found it to be slower than 4064, i.e., with jacketed bullets it approximated the burn rate of IMR 4350 in the .30-06 and IMR 4831 in the ..243Win. Treat it with respect since it isn't a canister powder, which means no undue compression, no overloads (almost the same thing), no duplexing, and don't stuff your cartridges full of it when the ambient temps. are >80 deg. F. Don't observe these common sense cautions and "squirrelly" pressures will be the least of your concerns.
What about 7383 and cast bullets? In cartridges such as the .308Win., 7.5 x 55mm, .30-06, and 8 x 57mm, it performs very well with heavier CB's and charge weights of no less than 37gr. (If you have a .308Win./7.62 x 51mm, you may want to check this figure). "Jim," who left Boolits and established his own site, developed a simple method to determine the max. charge of 7383 for a particular cartridge. To wit, take the cartridge in question, deprive it, then drill out the primer pocket. Seat the CB you intend to use to the OAL you typically use, then trickle in the propellant until it reaches/is level with what was once the primer pocket. Dump it out and weigh it; repeat this 3 or 4 more times, and you'll have a good approximation of a max. charge for that cartridge and CB combination. Btw, I've done this with both the 7.62 x 39mm and the 8 x 57mm and it works very well as it is a conservative measure since there's almost no powder compression.
Hope this helps!