Almost ready to load!
Getting there!
I've been prepping brass this week after the kids are in bed. My measurements told me I should probably turn another hair off the neck thickness. I borrowed some pin gauges from work tonight to measure the exact chamber neck diameter to make the final determination. I'm going about this very methodically.
Then I'll load a few dummys to get the seating length right on a few different bullets, since this is a hunting gun I'm just going to go with a generic 0.015" to 0.020" off the lands and see where that gets me on seating depth.
From the reamer print I suspected I'd have enough freebore to seat "light" spitzer bullets out further than would be a good idea. What it also means is that I have enough room for 225gr bullets if I want (and I do).
Picture number one shows three dummy rounds next to a .357 Magnum case.
Left to right: 180gr Hornady Interlock SSP (Single Shot Pistol), 200gr Hornady FTX, 225gr Sierra GameKing SPBT.
The GameKing is seated more or less to the base of the neck. I did not adjust the seating plug for each bullet, instead I set the FTX into the lands, and then adjusted the seater plug 1/8 of a turn at a time until I was between 0.015" to 0.020" off the lands, and then seated the other bullets without any adjustment.
All of the rounds feed and chamber fine from the factory two round box magazine without any modification. I can't tell you how relieved I am that no modifications are needed for efficient feeding. FWIW, the WSM action is a center feed action instead of the typical Savage push feed.
Based on a visual comparison the the bullet ogives, I should really re-do the seating depth of the 225gr GameKing as it's ogive appears to have a
slightly larger radius.
Picture number two is a small batch of brass for my first range outing.
With the pin gauges from work I determined that my chamber neck is 0.390" just like the bullet seating die. so I went ahead a turned a touch more off the neck thickness. The three dummy rounds average 0.386" at the neck.
A while back, before I had dies, I made a couple prototype rounds to get an idea of case capacity. Now that I have actual cases from the actual dies I have redone the measurements. Before I mention the case capacity, I will mention that the once fired, factory loaded brass I had, had very thick necks, 0.020" thick. Necking up to .35 caliber from the .25 WSSM parent didn't reduce the thickness much, to around 0.018". I'm happy to report that this bag of Winchester component brass started with thinner necks, and I assume thinner case walls as well because my case capacity went up a small amount. Filled with water, the finished case holds 56.8 grains of H2O. To the bottom of the neck, the capacity is 48.6 grains of H2O.
The good news is that this is exactly the same measurement, 56.8gr, that I get from a .358 Winchester case (actually I necked up a .308 case). I'm not saying that I should use the same load data as the .358 Win, only that there will be fewer assumptions.
The other good news about the wall/neck thickness is that less material needs to be removed to get the neck thickness to 0.013" to 0.014".
