6.5mm bullet, How low (weight) can you go with 8.5 twist?

[cncmill]

How light of a bullet (6.5mm) can I go with an 8.5 twist? 120gr. 100gr.? Also if I am shooting 140gr. now at around 3000fps, would I be safe to keep the same powder charge when I go to a smaller bullet? Smaller bullet less pressure?

 

[ShaneG.]

I have an 8 twist in 260AI and run 95g vmax in it along with 140 Amax. I raise my powder charge up from 43.5g with the 140's to 48g with the 95's with the powder I use in it. Velocity runs about 2900-2930 with the 140's and about 3500 I think if I remember right with the 95's.

 

[1shot]

I shoot 123 SMK bullets well with a 8.5 twist bbl.
Lloyd

 

[cncmill]

Thanks guys, that is what I was hoping to hear.

 

[2506]

You did not mention the caliber you have. You could get better velocity and accuracy out of a faster burning powder when going to the light bullets. Using the slow burners for heavy bullets in large cases gets you best velocity but drop down from 140 to say a 100 gr bullet and you need a faster burning powder to get your best velocity.

 

[cncmill]

2506,
Right now I am shooting a 20# BR gun, 6.5-284 with 140gr. bergers, 50gr. of H4350. I would like to build another 6.5-284 that is much lighter for shooting varmints. That is why I want the lighter bullets. Thanks for your reply.

Erick