jkupp
I am a previous 7stw skeptic. Looking at book data on pills up to 160 grains I didn't see the trade off between velocity and powder charge to be high enough. I actually bought a rifle expressly to pull off the barrel and go to a 7mmLRM. I was already a fan of 168 and 180 vld bullets, shooting the lighter in my two 7RM's. My RM's shot the vld's well, but I wanted more velocity, as I was only getting 2875 out of my 24" barrel, partly because that gun really liked RL19, instead of the slower powders. I decided to shoot a few through the near new barrel on my new STW before pulling it, and to my surprise the 10 twist 26" barrel shot the 168's into .5moa groups(ave) at 200-300yds so far at a consistent 3125fps. I have gotten use to the recoil of my 7RM with a brake, but do not find the recoil of the 7STW to be excessive, even at 8.75lbs, scoped. I push 74.0gr of 7828 behind a F215 primer.
Your biggest concern will be brass. Finding it isn't easy, though Nosler seems to be avail, but it is insanely expensive. I have cobbled together a small mix of Win and Rem brass. Starting my third loading on the Win and surprisingly have not had to trim it yet. I've shot 1000 rounds out of my 7RM's and always have to trim at least every other sizing, so I don't know why these seem to be better.
If you hope to buy factory ammo, I would reconsider the change. While they usually have some STW ammo, it is never consistent in what they have, usually some variation of the Nosler offerings.
My affinity toward 168 and eventually 180 grain VLD's is about the bc, but also about having enough energy to take down a bull elk at farther distances, so I have no interest in a really fast 140. I don't buy more speed vs. less bc, as I just don't see it after say 500 yards. So, while my 10 twist just so happens to shoot 168's very well, I am limited on 180's, so get an 8.5 or 9 twist, though I understand this will ****** your speed a bit.
Lastly, you need to consider bullet seating and your magazine. A main reason I was shocked this new gun would shoot the berger's so well is because I can barely seat over saami spec with my factory mag box. My bullets jump approx. .035", which is contrary to "most" who shoot these bullets. These cases are very long and the magazines are usually the same length as those found on a 7RM, so if you can you might modify your rifle.
I'm sure you know all this already, but I wanted to let you know that I was a skeptic, but am impressed. The books usually show no more than 50-100fps gain, at the cost of 8-10gr of powder. Getting 250fps more on a pill with a bc of .617, means a significant difference at the ranges I hope to get competent at in hunting situations(700+). My load is only about 5.0 grains more than what most would use of 7828 in their RM's, so 50fps per grain seems reasonable, though my extra 2" of barrel does help.
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