powder range gaps?

[styles]

I am reloading 45LC with AA#2 for a Ruger Blackhawk using Accurate's load data with LSWC 255gr. I started with 5.X grains and have worked up. I am now past the point of standard pressure 7.0 grains, but the +P range starts with 9.0 grains and goes to 10.6.

With 38 SPCL, the AA#2 data for standard pressure runs from 3.6 - 4.0 grains and the +p runs from 4.0 to 4.4. +p picks up right where standard ends.

Is there a reason the loading data for 45LC would have a gap like this and not call 7.1 grains the starting +p pressure? And; are there any downside consequences to being in this gap at ~7.5 grains?

I noticed the grains:velocity really falls off at 9.0 and I would switch to AA#5 before I loaded that fast. I think I am still pretty efficient with #2 at around 7.5 grains. 7.0 = 888 fps.

 

[dewey7271]

I would think what you're seeing is the 45 Colt data for differing revolvers.
The older revolvers are not really suited for some of the higher pressure loads thus the low range. I'm guessing you saw speeds in the low range top at 800-900 fps.
The stronger models, Ruger Blackhawk, Freedom Arms, TC, can handle higher pressure loads thus the higher starting point.
Are you ok in the gap? Shooting a Blackhawk, yes.

 

[murf]

there is no such thing (per saami) as +p loads for the 45lc. the loads you call +p are probably "ruger only" loads commonly published in reloading manuals. these loads are to be used only in the ruger large frame blackhawk, the ruger redhawk, the freedom arms revolvers, and contender single shot pistols. the large gap you see is the jump from loads under 14,000 psi (standard saami pressure for the 45lc) and loads from about 23,000 to 32,000 psi (the non-saami established pressure for the "ruger only" 45lc).

murf