Chrono Data
I load a lot of 38 Special - probably 85% of my bench time is loading for 38 Special. Mostly target ammo with 148 DEWC's, and 158 SWC's. I'll throw in some hotter +P stuff for variety, but most of my 38 shooting is for target and competition.
So I dug into my data to see what I have for 158 Hardcast/Bullseye. Oddly, I don't load that combo much (I usually use W231/HP-38 or Nitro 100 for lead 158's) Anyway, I have two loadings that I chronographed. This info is through a Smith & Wesson Model 67 with a 4" barrel. A 2" LCR will yield less velocity, obviously. Maybe in the order of -80 f/s or so.
3.4gn = 761 f/s.
3.5gn = 800 f/s.
I didn't work up any further because that velocity range was my objective. Notice how adding just 0.1gn of powder yielded 39 more f/s. Such is the nature of Bullseye. It is very fast and energetic. This is me expressing caution. Bullseye can bite if mistreated. It's good - check that - legendary for making extraordinarily consistent target level rounds. It can be pushed a little harder; but that's not really what is does best.