Voldoc02:
The Berger web site shows what the recommended twist is for each bullet weight they make in 17 caliber. Keep in mind however, its the length of the bullet that determines what twist barrel is needed and not the weight, but generally the heavier the bullet is, the longer it is.
Without knowing specific information about your rifle, and its rate of twist, I'll offer some general advice on the 17's.
With factory barrels, the 25 grain bullets will shoot well in a 1 in 10" twist barrel in most cases, but not always. If your barrel is a 1 in 9" twist it will handle the 25 grain bullets without a doubt and will most likely shoot the 30 grain bullets also.
If you go above 30 grains in bullet weight, its probably going to take a custom fast twist barrel (faster than 1 in 9") to stabilize bullets above 30 grains.
I have shot 17 caliber rifles for over 25 years and have pretty much settled on 25 grain bullets for most things and 30 grain bullets for something the size of a coyote. That has worked well for me, and it has been quite a while since I shot any 20 grain 17 caliber bullets. But, that's just my preference for the 17 calibers.
Incidentally, if you're not familar with it, Saubier.com is a good place to visit if you have small caliber interests. Be careful, however, as they have a very good "mentoring program" and will gladly help you spend your money. /ubbthreads/images/graemlins/laugh.gif A great bunch of guys with lots of small caliber experience. /ubbthreads/images/graemlins/grinning-smiley-003.gif To illustrate what I mean by mentoring, now that you have one 17 caliber, you'll probably need a couple more, and then you might want to branch off into the 20 calibers, too. /ubbthreads/images/graemlins/smile.gif
Good luck, the 17 calibers are addictive - pretty soon you'll have a whole bunch of them in assorted cartridge sizes. /ubbthreads/images/graemlins/grinning-smiley-006.gif
- BCB
EDIT: One other point. I just noticed you might be using a standard SR primer in the 17 caliber? The high pressure small caliber cases definitely need a thicker cupped primer like the Remington 7 1/2 or the CCI-BR4 primers, or the Federal 205M. If you don't use them, you'll get some pierced primers and needless bolt face wear - not to mention gas in your face. Not a good thing!
Here's a prettty good link for reading about primers. I believe the article is titled "Primers and Pressure".
http://www.jamescalhoon.com/articles.html#19cal
- BCB