twist and velocities,relation)

[constructor]

This question is just to get a few more opinions.
Do you think you can get more velocity from a 6br with a 12 twist than you can with a 8 twist? Do you think a slower twist would lower pressures enough that you could increase the charge to obtain more velocity with the same powder type and bullet out of the same length barrel?
Thanks in advance.

 

[expiper]

Findings not opinion...
I have found that the bore/groove dia....and number of grooves ...and cut vs. button rifleing ....are more of a factor than twist rate. I have used 14 twist bbls for 30yrs in 6mmBr and only in the last 5yrs have I been dabbling with 8 twist...nothing in between,, 10 or 12 forinstance))...I found that a 8 twist cut bbl will have aprox the same max charge as a 14 twist button bbl....with bullets from 60 to 80 gr.,the biggest my 14 twist bbls will stabalize) ...When I was breaking in my first 8 twist bbl. I reduced the powder charge that I used in my 14 twist bbls one full grain....the pressure was very low...I incresed 2#"s on my powder measure which brought the charge bak to where it used to be and things looked and shot normal,great!) .....I hope you dont see this as a non-answer....I found other factors to be more influential on the pressure and velocity than twist rate...Roger

 

[BoydAllen]

Excellent answer

 

[constructor]

Thanks, the first question was to get some better opinions on a topic that started on another forum. All the barrels I use are cut rifled. I have heard about some Scenars shooting better with a .0005 tighter bore.
After the above answers, Do you think a 4 groove Krieger would show less pressure than a 6 groove and Where would the 5R and 3 groove Lilja fit in? I may be able to get a 3R if I can get enough back up to show it may be worthwhile.

I know I should be more concerned with accuracy but these aren't benchrest rifles. We are shooting out to 1000 at unknown distances where flat is good but shooting a 338 Lapua all day is not. I have a RSAUM in 6.5 and a .243 that I may setup as a 10 twist to work with the new 95gr sierras. I believe they may have a better trajectory than the 115s and not give up much on the drift. thanks again

 

[expiper]

I too am anxious to get my hands on some of the 95 SMK's!!! I am supposed to do some field testing using them....just havnt recieved em from Sierra YET!!...buttt I am not going to ever spend my hard earned $$$ on a 10 twist bbl. that will not allow me to use 105-107 gr bullets in any 6mm configuration,,BR to 6mm-284)) ...the 8 twist will shoot the 95 smk just fine...it shure shoots the 95 VLD's JIM DANDY!!!,,,,I would not limit my bullet selection in a 6mm long range rig to the point I culdn shoot some of the most proven long range bullets....and "I" am very concerned with accuracy at any range,,especially at LONG range,600 +))....you need to forget about gaining 20-50 fps. MV and start thinking about MOA's of accuracy....,Fact not Opinion..hahaha)....dont worry about the groves and miss the point....I want accuracy, bbl life,lack of jacket wash, wide range of bullet choice, and Krieger 4 groove gives it all.....Roger