My idea is to reload on my S&W 625 .45 auto for target, using the Penn bullet 225 grains WCBB. a full wadcutter design seated deep into the .45 Colt case with 3.5 grains of N310 .Any one try this combination?

WILL NOT WORK!!! Rim on .45 Colt is too small and not thick enough, .45 Auto Rim cases use extra thick rim to equal thickness of ACP rim and moon clip.

Your 625 is NOT chambered for a 45 Colt. It is chambered for 45 ACP and 45 Auto-Rim.
The 45 Colt will not chamber in the cylinder (I hope).
DO NOT try this.

Another problem is the 45 Colt case is too long to fit in a 45 ACP cylinder. As Mack stated you need to use 45 Auto Rim cases or simply use a moon clip for your 45 ACP cases. As for the bullet you want to use I really don't see an issue with using that bullet.

As stated 45 colt case is way to long for chamber and even if you shortened it to 45 acp length it still would not work well because the rim is about .032 thinner than a 45 auto rim and you would have a huge headspace and the case would built up a lot of momentum and really slam into the recoil shield. BAD. Might not fire reliably if at all because firing pin might not be long enough to reach the primers well.

The only good way to fire both rounds in the same gun is to have 2 cylinders fitted or start out with a 625 in 45 colt and have the cylinder center portion relieved to use full moon clipped 45 acps. There is no good way to modify a 45acp cylinder to fire 45 colts and 2 so bad I would never do either.

If you want to fire rimmed cases get auto rim. But, with the correct tools full moon clips are easy to fill and unload. Makes reloading the cylinder easy and quick, brass clean up simple. Much better than any speed loader. I must have 100 full moon clips they are cheap. I load a whole bunch at home. Never mess with it at the range. For carrying around in my pocket at times I have some simple double clips that hold 2 rounds apiece. No bulgy pocket.

I like 45 colts and have several in S&W revolvers for both rounds. Where the colts shine over the acp guns is firing heavy bullets, 255 gr and up.

Thanks all for usefull information))