Different powder load for different 185 Grn Magnus bullets

Slide mount dot with 11# recoil spring and tight lock up - cycles the Magnus 801 hard cast BN with 3.7 VV N310. 

To get the 811 swaged WC to cycle, I have had to go up to 4.2 grn N310 (by .1 grn steps). 

Measuring the base to shoulder, the 811 is roughly .095” shorter.  Is that larger case volume (due to shorter driving bands) all that is behind needing .5 grn more powder to cycle?  Expansion, seating, crimp etc. are all the same.

You have a softer bullet with less barrel resistance so more powder is needed to develop pressure would be my guess. Just posted on that called " Soft bullet test" l think

My experience was a .2 or so grain difference between the swaged 200 and the swaged 185. 11lb recoil spring, 18lb hammer spring, and 3.7 BE with the 200. Same as above and 3.9 BE with the 185. These loads are summer loads. I seat on the shoulder so the OALs and the length from the head to the shoulder is the same. 

Jacketed shortline will work at 4.1 but I shoot 4.3 for everything with the 185 jacketed

Also check the diameter of your bullets. I bet you will find that one is on average slightly smaller.

In the past, they both measured out at .452.  

Would smaller bullet take more powder because it take longer to seal the barrel?

I've never shot the swaged 200, just the hard cast 200.  Is there much of a difference between those two swaged bullets in the shoulder to base dimension?

There is some, because the nose is the same. But the big difference that I found between hardcast and swaged was diameter. 

Measure a sampling of the bullets that you have and decide for yourself. 

I shoot alot of swaged bullets at the shortline and in practice.