7mm ultra mag load development

Go for book data with retumbo or rl25 to start with.
I'm using retumbo with 171-175 grain bullets in my 7rum.

I had a prior 7rum shooting well with 95 gr rl25 and 140sierra or nos ab.
With the 140's I'd start a work up with the goal of 95 gr rl25 using rp brass and 215's. Load to max mag length... around 3.650" on most remmy rifles

If you want to work with rl50 I'm shooting 168 berger vld's on top of 95gr rl50 lit by a 215; it seems like a good load so far but hasn't been pushed to the max.. You may get to 98gr with a 160 with no issues... work up of course. I haven't chrono'd yet but it shoots well in my pipe.
 
for 140 AB I had the best luck with IMR7828 (I run 90.6 gr) and rem 9.5M at about 3400 fps-easy and consistent. Can run much faster with 25 or retumbo but this had better accuracy for me.
for 150 Partition I used a VERY stiff load of RL 25 and Fed 215. (work up to your own max for your rifle)
for 160 AB (accubond) between 92 and 94 gr of Retumbo
 
Thanks for the help guys.. I got about 40 brass for it now so it's time to start playing...seems like a very impressive caliber can't wait to stretch it's legs out!!
 
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