Cartridges based on the .30-30 seem to be 52mm long. THe metric designation of the .22HP SAvage is 5.6x52R, I have some for my Savage 99s,. and apparently the Euros call the .25-35 the 6.5x52R, see http://gunbroker.com/Auction/ViewItem.asp?Item=121879365 and http://www.auctionarms.com/search/displayitem.cfm?itemnum=8972734
Are the .22HP and .25-35 cases longer than .30-30 cases?