6.5 mm cast boolits

[Sandgroper]

Will do.

[meles meles]

Our requirement is for the round to be sub-sonic when fired from a 22'' barrel, and to have plenty of energy - hence the thinking that we need a heavy bullet. Perchance we need to identify the rate of twist in the barrel and let that guide us as to the maximum size and weight of bullet to use?

[dromia]

Twist yes that would be helpful but also the nature of the throat as this will have a considerable effect on how heavy a boolit you can use. Also a longer boolit will take further to stabilise at these lower velocities.

Again there is not enough information such as rifle type and why you feel you need high ft/lbage, not to mention groove diameter, throat etc.

If you want informed help then you need to give more specific information.

As in everything to do with cast boolits fit is king and untill we know what the boolit has to fit and what it has to do then it is all conjecture and the best you can get is a plethora of best guesses and my boolit is better than your boolit posts.