With the stock 10 lb spring that is included in the package, the Coonan will only cycle 38 +p. To shoot the regular 38 specials I had (130gr FMJ AE), I picked up a Wolf variable power spring kit, with springs from 5lbs to 9lbs, so I could play around a bit. My Coonan functioned reliably with the 6lb spring.
One thing to keep in mind is that the Coonan comes with a pretty strong mainspring, which works in tandem with the recoil spring to control with 357 mag (probably one of the reasons Coonan recommends a 500 round break in with 357 before shooting 38special). I spoke to Ray at Coonan and he told me that if someone wanted a more dedicated 38special package, swapping in a lighter mainspring as well would be the way to go for a smoother functioning gun. I can see that as after the 38 spec recoil over comes the mainspring, there was not much juice left to cycle the gun. Shell casings were dropping within in a foot or 2, and cycling was a little slow. Lighter mainspring and heavier recoil spring would speed things up. But anyway, I didn't want a dedicated package as I shot mainly 357, and the lighter Wolf springs with 38 special functioned functioned fine for my needs. The low power variable spring kit from Wolf would be my recommendation.
Reasons someone might want to shoot 38 spec are because there is basically no recoil (so its great for a wife, daughter, someone with some arthritis, or anyone that doesn't feel the need to shoot full-house loads all the time), and a lot of folks already have a stock of 38 special ammo.
