In the VLD bullets, I think that you will have to stay under 70 grains. As pointed out the 70 grain Speer are a semi-pointed bullet and should stabilize without a problem. Every gun is a thing unto itself. The velocity you push them to also has an influence on bullet stability. You will have to buy a box of a likely bullets and try them. You may find that they will not stabilize at starting loads, so you will have to work your way up until you reach a velocity where they will stabilize. DO NOT exceed recommended powder charges however. If you reach maximum pressure before that then you must stop at that point too and go with a lighter bullet. If you have a chronograph STOP when the bullets reach maximum published velocities. I would think that any bullet no matter the shape would stabilize if it is 65 grains or less. You never stated the intended purpose of this gun. If you are using it for hunting and want a heavy bullet your best bet would be the Speer 70 grain. If you are looking at precision long distance shooting then the VLD bullets are your best bet. Do not over look the 55 grain Bear Claw bullet for hunting. It is a long bullet for it's weight, so it is only 55 grains, but performs well on deer sized game. Bullet length (not weight) has more influence on what twist it takes to stabilize a bullet than any other factor.