@the range

[TucoTom]

204 Ruger
Sierra 39gr. BlitzKing
IMR 8208 @ 27.2 grs.
CCI BR-4
OAL= .001 off rifling
1.488" @ 200yds. 8shot group
avg vel 3726fps
sd=22.1

204 Ruger
Berger 35gr. FBHP
Benchmark @ 26.5grs.
cci BR-4
OAL= .001 off rifling
1.930" @ 200yds 8shot group
avg vel 3754fps
sd=21.9

[bow shot]

I bet you feel like this:

[TucoTom]

Well accually I'd like to figure out how to lower the "sd"........

[milkman]

No pics?? This didn't happen. haha

[jo191145]

Have you tried backing away from that rifling? A lot?

[TucoTom]

I'll give seating depth a try....

I'm thinking neck tension??

[jo191145]

Neck tension or at least consistency of neck tension is crucial in any cartridge that is off the lands. You fail to mention what gun or what your COAL is but most 204's have an extremely long throat.
I personally have never found the best accuracy anywhere near the lands in a 204 factory rifle. My favorite all time accuracy winner was the 35 Berg. 2.265" Coal was always a basic/ favorite measurement. If it wouldn't shoot at that depth it wouldn't shoot anywhere and I switched bullets to whatever that barrel might prefer. Very seldom did I switch bullets.

I've developed loads with the same COAL and light tension and same COAL and powder with tight neck tensions. Besides tension the only thing that changed was the powder charge required to bring accuracy. Some powders do require more tension. Most do not, its just a matter of finding the EXACT charge.