[gpwelding1]

i have .45 acp brass with large and small primer pockets.im going to reload them both,but do i use the same amount of powder with the small primers as i do with the large primers?

[beatledog7]

New primer, new work-up.

[ReloaderFred]

I load them the same, but I'm not loading maximum loads, either. I can tell no difference between the two.

Hope this helps.

Fred

[Ky Larry]

As b.d.7 said, anytime you change a component, start at the bottom and work up.

[mbopp]

Somebody over on brianenos chrono'd loads with small and large primers. They lost 25-40 FPS with the SP cases. Kinda tells me you can use the same powder charge but the velocity will be different, and the SP cases should develop lower pressure for a given powder charge.
Target loads I wouldn't worry about. If you have a max load already then yes, reduce the charge and work back up.
FWIW and YMMV, small primer cases give me better accuracy when bench testing loads. For USPSA ranges you're splitting hairs, but 50 yard bullseye may be another matter.

[Hondo 60]

Start low & work up.
But in the end, you'll probably find that yes, your load is the same.

At least that's what I found.
Using my chronograph I found no statistical difference using Remington 2 1/2s (Large) and/or CCI 500s (small)
with 4.1 gr of Tite Group & a 230 gr Berry's RN

(the data is low end for lead, but it cycled my 1911 just fine & produced about 800 fps)

[blarby]

http://www.thehighroad.org/showthread.php?t=649476

[coalman]

The are pretty much the same. IMO, other than as a parroted response, no need to "start low and work up" unless you are running very top end loads. We're talking .45acp afterall which is more foregiving than low volume case loads.

[ArchAngelCD]

I haven't loaded any of the small primer .45 brass yet but everyone I know who has told me they are using the same exact loads and they see no difference at all in performance.