My only .38 Super is a 1937-vintage Colt Super .38 Automatic, well used before it came to me but a nice example of the days when pride in workmanship was a little more apparent than we see today.

My pistol is not very finicky about ammunition. Anything that passes the "plunk test" and fits in the magazine tends to function just fine. I have resisted any urge to explore the performance envelope of the .38 Super cartridge in deference to the age of my pistol. I shoot reloads exclusively, and tend toward modest performance levels. No need to batter the old piece, or worry about heavier recoil springs.

Nominal bullet diameter for most pistols is .355" (jacketed) or .356" (cast), like the 9X19. In my pistol I have had very good results with cast SWC bullets of 140 grains, sized .357", modest load of 5.0 grains Unique for about 1000FPS. Functions well, accurate, not excessive in any way.

One nice feature of the .38 Super is that the case is truly straight-walled (cylindrical) rather than tapered like most semi-auto cartridges. A carbide sizer die will produce very good and consistent results and allow bullet seating with good neck tensioning and consistency. I use an old Bair steel sizing die for 9X19 to apply a moderate taper crimp on my cast bullet loads with good results.

My pistol will accept just about any jacketed or cast bullet combination that passes the "plunk test" and fits in the magazine. Yours may or may not do so, and some experimenting may be necessary to find out what parameters your pistol requires.

You can hot-rod the .38 Super to performance that rivals .357 Magnum with the lighter bullet weights, but I see nothing to be gained by that. Enough is enough!

Your pistol is shown with fixed sights, appears to be a staked front sight and drift-adjustable rear. Many Colt pistols I have used from the 1970's and 1980's have been "challenged" by shooting to point of aim. Short of altering your sights you may be limited to changing the rear sight to achieve POI to POA, if your pistol is like some I have experienced. Not difficult to do, and compatible sights of various heights are widely available. Of course, unless the factory sights are way out of spec the easiest correction is experimenting with different ammo or handloads to achieve acceptable results.

Have fun with it! Very nice pistol!