Hello acloco:
I must chime in at this point. I have read allot and used quite a bit of Hodgdon 'extreme' powders such as H4895 but with less than satisfactory results. From what I have read and a bit of experience with the .204 I think that your powder selection may not be the best. H355 or BL-C(2) might give better results. BL-C(2) fills the case better. Also, you can have a cold weather as well as hot weather load so temperature sensitivity can be address with ball powders. Also does your C.O.L. put you near the rifling. In my .204 I can reach the rifling with a good 0.100 inch of the bullet in the case. Yhis could be an important variable. At any rate it appears that you are making progress and I want to wish you success. I will be watching your posts for ant .204 related info.
McLernon
First off - I have said this before....but THANKS for the info, tips, suggestions, kind words, and words of wisdom!!!!!
McLernon - I have tried everything but BLC-2. Do you mean H335?
Varget, H335, H4895, Benchmark, H322 , AA3460, IMR4198, IMR4064, & IMR3031 are powders that I have tried.
Have tried the following primers - CCI400, CCI450, BR4, WW, 7.5's, CCI 41's, Fed 205, Fed Match, and couple more that I have forgotten.
I am going to try Reloader 15 - that should definitely give me a good case fill. But, ugh...will have to work that up with various primers. I think I have 15 left of each of the flavors. Of note, kind of an interesting powder, judging by the load books...a little faster at the muzzle with lower chamber pressures. HMMMMM!!!
Yes, have tried getting closer to the lands on the bullets. Within 0.015"....and same as you...end up with 0.105 left in the neck (don't have my notes in front of me...but that was close...it IS under an 1/8" (0.125").
If nothing else, through this process, if you drop a small rifle primer on the floor, I can identify that puppy by the color! LOL!