Reloading Belted Magnums (.300wm)

I shoot 300 WM in a Savage 116 with factory barrel. My load is 73.5gr of H1000 under a 200gr ELD-X at about 3.46" COL (mag length). Federal GM215M primers. I measure base to ogive so it varies slightly depending on the bullets...I had to sort the bullets on base-to-ogive measurement in 0.001" increments to get groups under 1/2" at 100 yards. The widest spread on the ogive was 0.020"! Which is visible to the naked eye if you put them side to side. Most were within a 7 thou band but I load them in 1 thou groups. My dies are regular Lee dies. I tried the collet neck-sizing die but group size didn't change noticeably over bumping the shoulder a couple thou with the FLS die. A micrometer seating die that pushes lower on the ogive would be really nice! With the Lee die I get 2 thou variation on CBTO measurement even with the sorted bullets. So I go through and measure each one and bump the long ones in another thou. I'm using Federal brass that I sorted by water capacity and tossed the extremes. Also primer pockets uniformed and flash holes deburred. Best group at 100 yards was 0.406" with around 0.3" vertical spread. At 600 yards I'm seeing about 2" of vertical spread. I haven't calculated ES or SD - I just go with what the 600 yard target is telling me!

I had good luck with IMR7828SSC but then it got pushed out of the accuracy node in hot weather. I love H1000 for its temperature stability. I don't get the same velocity as other powders but it's better for hunting in varying weather. Also tried Retumbo and IMR 4831 with Berger VLD 190 and 210. Decent sub-1" groups but not much better than that. They were jumping about 0.080" to the lands.

I have 3 firings on my Federal cases and haven't had problems with the web expanding too much to chamber. Primer pockets are getting looser, though.
 
TrevorJ said:
I use a Lee collet neck die, Redding Body Die, and Forster Seater.
I had been using H4831SC, but recently did some load development with H1000 that showed improvements using the same components (Berger 210 VLD's, PRVI Brass, and CCI 250 primers).
Try both powders, you already have them.
Click to expand...

Those are the exact dies I use as well.
 
I know you didn’t mention retumbo but it works great for me in the 77 grain area. Mine is custom throated for the 215 Berger’s but I found the 212 eld x shot to the same zero at about the same speed with the same powder charge (2900 FPS with a 26 inch tube). Interestingly both bullets use the same kestrel solution. For dies I use Redding full length bushing dies and seat both bullets about ten thou off. PRVI brass has been good for me.

Is there enough room in the detachable mag to reach rifling?
Does that rifle come with a thread protector as well as the brake?
Thanks
 
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