How to estimate MV when necking up

[aixenmemphis]

Is there a formula used to estimate MV of a larger caliber bullet out of an existing case such as a 27 cal bullet out of a 6br case. Thanks for any info.

 

[Kodiak99317]

Here one I did up long ago. The data in the top left of the spreadsheet,variable section of the internal balistic calc) is for a 6BR with 105g Berger's with a 27 1/2" barrel in 8 twist I think... I keep it for wildcats,I have a few) and Excel match index lookups samples... see the recommended powder lookup formula!!

Change the bullet diameter, length, weight and boattail measurements and look way down for recommended powder type, charge weight and est. velocity and pressures.

THESE ARE ONLY ESTIMATES BASED ON THEORIES IN A LOT OF BOOKS FROM THE LIBRARY and a few other sources and only as good as your case and bullet measurements...

It worked for my 6-250, a buddies 30x1.??, my 30x47, my 22MR wildcat and few others and it closely agrees with the QuickLoad pgm for pressure etc.

Keith

 

[aixenmemphis]

Thanks for the info guys.