Reduced rifle loads
Ok so in the past when I wanted reduced rifle loads I always just grabbed H4895 and ran 60 to 65% of the max load for a given bullet and shot happily. But I am out of it and who knows when it will be available again, I cant count on it anytime soon that is for sure.
So the question is this I have the latest Lyman Cast bullet manual #4 and there are a huge number of cast bullet loads with a variety of powders that I have or can get my hands on readily enough are these lead loads safe to run with jacketed bullets? I dont want a under charged detonation situation going on as we all know all manuals say not to reduce the min load recommendations on their charts but then here are cast loads doing just what I want for velocities so...
Specifically I am trying to find a load to run in the 270 that will push a 140 Ballistic Tip in the 2000-2200fps range for a buddy to start his wife and kids out that would be enough to hunt deer with this fall. I have about 800 of these bullets and at these slower velocities they should be the cats meow for them as the 223 they have been shooting is not legal in Colorado to hunt big game with. The manual lists Unique going up to 2100fps and IMR4198 going 2200fps, both are on the shelf. I would lean towards IMR4198 but I dont really know why other than it will fill more of the case.
Whats everyone's experiences here who has tried it? What should I watch for? So on and so forth...
Richard Lee's 2nd edition "Modern Reloading"
by brionic 
, Tuesday, September 03, 2013, 22:01 (4092 days ago) @ Fowler
contains a neat section on reduced loads, with cast and jacketed.
He provides technical info on the how and why, and specific loads for 30-30, .308, and 30-06. Beyond that, he provides "pressure factors" for specific loads with particular powders, and a formula for how to determine your own reductions. The pressure factor is a decimal that allows you to calculate either pressure or velocity reduction for every 1.0 grain powder reduction.
For Varget, with a jacketed 140 gr bullet, the pressure factor is .979. Using the maximum velocity of 2772 fps/43.7 gr Varget, multiplied by .979 for every grain reduction, it appears that a 12 gr reduction of the maximum load would yield a velocity of 2,150 fps.
Other powders that include pressure factors for the 140 grn are H450, H380, H4831, H4350, H414, and H4895.
Don't take my word for it, though. The book is a good read, and is worth the price.
I can scan the pages if you are interested, but the explanation on bullet pressure and how to perform the calculations bear reading.