Here's some general observations on PD rounds for 2" barrels.
I started carrying an M&P 340 (13.3 oz) last summer, and I wanted to become proficient with it. To do that, I've been working with both the Rem 38S12 (and the Georgia Arms 38E reload) and the Speer 38+P GDSB 135-gr. rounds as models in building "replica reloads" so that I could afford the practice and training I wanted to do. Ten months later, I've shot about 9,000 rounds through a 640 (23 oz), 1100 rounds or so through the 340, another 300 rounds through a 442, and 500 rounds through an M60-3". Many of the reload recipes and the factory rounds have been chronographed.
For novice 2" shooters, particularly with lightweights, it is more important to replicate the "feel" of the round, not the ballistics performance.
Performance:
1. The Speer GDSB 38+P 135-gr. round runs about 860-900 fps from my 2" revolvers.
2. The FBI loads run about 800+to 820, based on Stephen Camp's tests. Keep in mind that this round was originally developed for 2.5" to 3" barrel guns, and the fabled "LEO-only" loads from the 1970s ran about 870 fps.
3. The FC 130-gr (129gr?) 38+P load ran about 860 fps.
As you may know, brassfetcher has run numerous tests on PD ammo; see his gelatin tests. The Speer GDSB bullets were, AFAIK, the first bullets to be tuned to operate well at low-to-moderate velocities. The FBI-load bullets--a lead SWC, with an HP to possibly provide expansion, really do operate differently, as Jim March points out.
4. Because of one's "muscle memory" once you're proficient, the two rounds will shoot to a different POA. I started developing 'replica reloads' for the FBI round this winter--and I do shoot about 1"-2" higher at 10 yards with this round.
Shooting proficiency:
1. If you're shooting a lightweight, there is no way around needing to get your hand conditioned for shooting either round well. Although I've been a tool-user, I was out of shape last year. To begin with, I carried the FC non-plus-P 110-gr. round--and I could barely shoot a cylinderfull from the 340.
2. A lot of practice will develop the "muscle memory" you need to shoot accurately with either type of round, but that is different for each bullet weight. I carried the Speer round until the weather got cold; then I started carrying the the Buffalo Bore 20A(?) round-- the 158-gr LSWC-HP round that runs 1000 fps from a 2" barrel. (They actually do; I chrono'd them.)
3. Unless you are a very experienced shooter to begin with, you need to practice with the round you carry. Since I am a reloader, I was able to use Speer's data for reloading to develop a replica in subjective recoil (and in similar ballistics, but that is coincidental). Once that was sorted out, it was easy to "back up" the charge weight to produce less recoil, but still felt the same. I then used the ed. psy. concept of "successive approximations" to build my proficiency.
4. A good basic drill is Old Fuff's "quad five:"
5 yards
5 shots
5" circle
5 seconds.
FYI, one can build "replica reloads" with lead cast bullets of
1. the Speer round for about 10 cents each, and of
2. the FBI load for about 11 cents each.
If you choose to use the actual factory bullet, (the Speer 135-gr GDSB, or a Speer 158LSWC-HP), your costs will be about 26 cents each or 15 cents each.
So, whichever round you choose, Moonclip, stay with it, and practice--a lot.
Jim H.
