Gmdr data

[XWrench3]

i, like many of us here, have used the data that these nice people have shared with us ( http://www.gmdr.com/lever/lowveldata.htm ) for several years. but the one thing that has always bugged me. at least in the calibers & powders i shoot. most of the time, it seems like the further up in charge weight you get, the larger the group size as well. does anyone have an idea why this is? (i am STILL learning) velocity itself should not be the culprit. as there are plenty of accurate fairly high speed loads for cast boolits. 2 things cross my grey matter. 1) the ignition of the larger amounts of pistol powder sets off a vibration with enough amplitude, to start the barrel vibrating. and 2, its the impact of the boolit into the rifling that sets it off. or, i guess it could be a combination of the two. (double trouble). or am i not seeing the entire picture here? i know that lever guns, structurally, are not as strong as a bolt action rifle, supported by a full 1 piece stock. which will make them inherently less accurate. but with the proper support, i can coax 1" groups from both my 30-30 and 45-70 Marlins. but i have considerable more trouble getting that accuracy with cast projectiles. by the way, just so i do not catch as many flames, i do know that kind of accuracy is not needed for hunting. and if i do not get that for hunting, i do not whine and moan. but for target shooting, i try to get the best i can, mostly because targets seldom run after being hit. and a lot of power is not needed. a very accurate target load, lets ME know just how bad I am shooting. and an accurate load means i can not blame anything but me.