confused about winchester cxp ratings on calibers

[rwmcquigge]

i am wondering how winchester can rate .303 british at the same cxp rating as a 30-06,300 wimag ect,these rifles are rated at cxp 3 and so is the .303 brit.can any one tell me what makes this bullet rate like that when it is only trvelling 2450 fps with a 180grn pill.their are calibers that are more powerfull but only rate a cxp 2. thought i would throw that out their, if any one can help it would be appreciated. thx

 

[Mannlicher]

read the article here, and you will have a better idea of what is happening re CXP ratings.

http://www.chuckhawks.com/cxp.htm

 

[one-shot-one]

just a starting point guide

as the artical said cxp is the expansion of the bullet not the weight/velocity as far as i'm concerned there is a lot of overlap in these ratings.
in certin situations and conditions a round from class 1 could be used on game in class 2, rounds in class 2 could be (somtimes) used for game in class 1 or 3, just be aware that they are not optimum for those game animals and extra effort by the hunter towards range and shot placement will be needed.