If you shoot a lot of ammo loaded in .44 Special brass in your S&W 69, you're likely to get some carbon buildup ahead of the case and it could be harder to load full length .44 Magnum rounds into the cylinder. That happened to me when I was shooting ammo loaded in .44 Special brass in my S&W 329PD, so now I only use .44 Magnum brass for all of the ammo that I load for that revolver and the carbon build up is no longer an issue.
I'd also recommend that you consider sending your S&W 69 to Ahlman's in Morristown, MN, to be turned and to have the forcing cone reamed. The $70 that they charge for an "action job" tune up is one of the best values anywhere and the $15 that they charge to ream the forcing cone eliminates the possibility of lead shaving. I send all of my "shooter" revolvers to Ahlman's for those 2 jobs and haven't met anyone yet who had that work done and didn't think that it was money well spent.
www.ahlmans.com
