The Firing Line Forums - View Single Post - Sticky bolt lift, how much to back off or not

HiBC · December 8, 2019, 10:42 PM

houdawg,I'll toss it out there again.

I get it that you are focused on the accuracy you got with Varget. That matters.

I picture the powder burn rate and the bullet acceleration being in a race going down the barrel.

If the powder burn is outrunning the bullet,pressure spikes.

Another bad analogy,would be a dragster's engine power curve versus gearing.

If you have a 7000 rpm engine,it might be that 3,00 rear end gears are too tall,but something like a 5.36 might be too deep.

There is a balance to achieve

If I was using 105 gr bullets in a 6mm,if I was loading up around max with a mid range burn powder like Varget, I'd sure look at shifting gears to a slower powder. Especially since you have 29 in of barrel to burn it in. I'd at least experiment with a 4350. Just to see. Maybe RE-19.

Good luck!

If someone had Quickload(I don't) it will give you a percentage of powder burned in the bore.That might be interesting to play with. Given your 29 in bbl,I wonder what the %of Varget burned would be if you plugged in a parameter of 24 in bbl. What if its 99 or 100 % burn at 24 in?

December 8, 2019, 10:42 PM	#32
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,288	houdawg,I'll toss it out there again. I get it that you are focused on the accuracy you got with Varget. That matters. I picture the powder burn rate and the bullet acceleration being in a race going down the barrel. If the powder burn is outrunning the bullet,pressure spikes. Another bad analogy,would be a dragster's engine power curve versus gearing. If you have a 7000 rpm engine,it might be that 3,00 rear end gears are too tall,but something like a 5.36 might be too deep. There is a balance to achieve If I was using 105 gr bullets in a 6mm,if I was loading up around max with a mid range burn powder like Varget, I'd sure look at shifting gears to a slower powder. Especially since you have 29 in of barrel to burn it in. I'd at least experiment with a 4350. Just to see. Maybe RE-19. Good luck! If someone had Quickload(I don't) it will give you a percentage of powder burned in the bore.That might be interesting to play with. Given your 29 in bbl,I wonder what the %of Varget burned would be if you plugged in a parameter of 24 in bbl. What if its 99 or 100 % burn at 24 in? Last edited by HiBC; December 8, 2019 at 10:48 PM.