Re: Rebarrelling a Savage
You might want to be more specific about you're idea of "longer ranges". Some of the guys on this forum shoot from one zip code to the next.
Distance, wind, pelt damage, etc might affect your bullet choice and in most cases, I think the desired bullet would drive your decision for the twist. However, 6mm, 6.5mm, 270, 7mm, 30cal all seem to have better/broader selections for bullets than 25cal.
I beleive 1 in 10" twist is pretty standard now days for 25-06.
You might want a little faster twist if you can get one in a pre-fab barrel and if you intend to mainly shoot the longer/higher BC bullets. (115-120gr)
Anything slower than 1 in 10" may severly limit your ability to use heavier/longer bullets.
I have a 25" Shillen on my Model 70. It has a slow twist, 1 in 11". But, it shoots 80gr Barnes TTSX just under MOA at about 3700 fps. It's pretty flat shooting: +.8" at 100yds, 0 at 200yds and -4.5" at 300 yds. I haven't validated the trajectory past 300 yds. But, that bullet has a BC of .316 as compared to the 115gr Berger at .466.
Hence, I feel that wind becomes a significant concern past 300yds which more than offsets the flat/fast shooting from the lightweght bullets where getting on a coyote and taking the shot quickly is your intent.
I haven't had much luck with Berger VLD or Swift Scirocco in that rifle (~1.5-1.75 MOA). ...likely due to the slow twist.
Hope this helps,