Actually, I haven't really started casting yet, just done a little bit of lead hoarding and some initial smelting/cleaning. But I have been reloading jacketed bullets for a few years, and this seemed like a fun next step. After reading the FAQ's and stickies, and spending far too much time on the lasc.us website, I think I'm starting to understand the basic concepts of fitting the bullet/boolit to the barrel.
Before I go order the mold, I would like to bounce a few questions towards all the knowledgeable people in here, so I don't waste time and money on something that would not work well.
My plan is to start casting plinking/practice GC-bullets for the 404 Jeffery (~.423), somewhere in the 350-375 grain area - hopefully being able to drive them at ~2000 fps, perhaps up to 2200. Design-wise I was thinking some type of bore-rider with a decent meplat, looking somewhat like Accurate molds #42-347J http://www.accuratemolds.com/bullet_...=42-347J-D.png. The looks of the bullet are not super-important though. Plan is to powder coat, rather than pan lubing. Use the softest alloy which works. 2-inch groups att 100 meters, and I would be very happy.
Questions:
1. Barrel is slugged to .4245, which makes me think it is safe to fire bullets sized to .427, correct? (twist is 1:14 i think)
2. I've not seen any gas checks specifically for the 404, but the online design program at Mountain Molds specifies that the 44 cal (.430) gas checks can/should be used with the 404 designs. So gas checks have been ordered already. Would seating these in the LEE push through sizer (.427) work fine? (I believe that it will, and since these are my first attempts at this I will not be buying a lubrisizer/lubamatic, just yet). Also going for a more exact match (.425 or .426) would mean a special/custom order for the sizer as well.
3. Should I do a chamber cast, just to know the exact dimensions? The barrel is a Lothar Walther on a Sako action, so I believe I will be restricted by magazine length before being able to seat the bullet far enough out to "kiss the lands". Am I in trouble with too short C.O.L?
3b. Assuming the .427 boolit scenario above is deemed OK, would I need to get another, larger expander for the reloading die? Brass that I've resized right now has an internal neck diameter of about .419, so this is perhaps too much neck tension for lead...
4. I will need a tool for belling the case mouth a little anyway, even with a slightly oversize GC, right?
5. Am I overthinking this? There are so many little details where the novice gets nervous, because of lacking experience..
Thanks in advance.