They don't have a groove do they? I'd suggest a barely detectable crimp. After the first shot in your revolver measure the overall length of the other cartridges in the cylinder, see if they're getting longer. Increase the crimp until they don't stretch more than .010". That's what I'd do.
I'm a huge Berry's fan, but I switched to X-treme bullets for use in my 44mag. Berry's says no magnum loads, and there's no crimp groove. X-treme says 1500fps max, and there's a groove. I do a very light crimp in any event, groove or no groove. I've seen Berry's spray a shotgun pattern at 1200fps (their stated max). Slower powders may reduce the shotgun effect as well.
H110, SRH, X-treme240, cheap and effective for 44mag.
--edfardos