CCI300 or Win. WLP for slower powders?

[50BMG]

I started working up a deer hunting load for my 1911 10mm guns using cast boolits (last year's loads were all JHP varieties ).
I am trying some cast projos from Montana BW (165g,180g w/GC, 185g & 200g w/GC).
AA#9 is what I have been using for my hunting loads thus far...
I'm normally the kinda guy that prefers higher velocity/flat trajectory loads using lighter weight projos, especially with an iron sight gun which may be shot at 75+ yards, but I've decided to load some heavier lead slugs this year.

I pulled a few recipes off the site here and while I did get some decent accuracy, some of the loads where a bit warmer than I felt comfortable with, so I dropped the charge weights a bit. The lower velocities got rid of the pressure issues but the accuracy fell off as well...
I normally use CCI300 primers for all my other calibers I load which take that size primer, but most of the manuals I have show the use of WLP primers for 10mm.
Might the WLP/semi-magnum primer be a better fit for this slower powder, especially since I've seen accuracy fall of with the lighter loads?

I'm also thinking of messing with some other powders. For projos in the 180g weight range my thoughts are Blue Dot or BE86... Having loaded magnum size rifle loads for years including .50BMG, my success in those with heavy projos in front of slow powders touched off by magnum primers may be handicapping my decision process here..

[The_Shadow]

You could try CCI350 or WLP to see if that helps.  But be sure that you are not over crimping the case and squeezing the cast bullets slightly smaller, that can mess up the accuracy.

I have always like Blue Dot with my cast bullets checked and non checked.  Power Pistol and BE-86 show good yields also.

[mr.revolverguy]

I did not try CCI350 but I do not really believe (gut feel here) that a magnum primer is needed for AA#9. I tested the same exact load with CCI300 and WLP here https://www.youtube.com/watch?v=kUmZV6BeV2Y saw very little difference.