6mm br velocities

[mitchellchandler_au]

I have just finished doing some testing on the 107 smk using 28.5 gn of varget in my 6mmbr. iam using a 28 inch barrel, it shoots groups around the .180-.200 mark. I was wondering if anyone knew what sort of velocities iam getting.and will it be enough for 600 yards.

Thanks for your time.

 

[memilanuk]

For reference: some people are shooting 31+ gr Varget and getting 2900+. Others,including myself) are maxing out around 29.5-30gr Varget and getting barely 2700-2750. Unless you have a *very* fast barrel... your load sounds a bit light to me.

As far as whether it's fast enough for 600... it'll get there, to be sure. Whether it'll buck the wind enough probably has a lot to do on how well you can read the wind, and how tight you can hold at distance. 2700 gets the job done for me, but I'd sure like a bit more, no doubt about it.

YMMV,

Monte

 

[jb1000br]

Monte -- sounds like a slow lot of varget...have you tried R15?

JB

 

[memilanuk]

Debating it... whether to screw w/ a good,accurate) thing or not... and it's not a slow lot of Varget, cuz it's been across a couple 8# jugs and multiple 1#'ers in between... the .308 velocities out of the same jugs have been spot on. I'm not the only one, JB.

 

[jb1000br]

wierd...

I could only get 2850 out of 31.4 varget, but 30.8R15 will easily add 75fps or so to that...

JB

 

[Hipshot]

In my 6BR with 26", 1:8 twist barrel I discovered two nodes using varget. One at 26.5 and one at 29.5. The mv's are 2650 and 2900, respecivly. I've been using 26.5 for my shooting.

I look for accuracy over velocity for my 300 meter shoots. I would like a good barrel to last a few matches more than what I'd get with the hotter loads.

I'm shooting naked 105 Berger VLD's seated a few thou' into the lands. However, this weekend I intend to get out and load some Moly 105 Berger's and increase powder in small steps to see if and when I get a good group.

BTW, in this month's issue of Precission Shooter there is part 1 of a 2 part story on bullet shape and position as the bullet begins its travel down the barrel. The article relates to slight skew of the bullet that leads to innacurate flight. Pretty technical article, relating to tanget ogive vs. secant ogive for short vs. long range use, as well as leade angle and seating depth. I read the article twice, took a Tylanol and went to bed

 

[mitchellchandler_au]

Could you guys tell me what sort of velocity i need to achive to have any chance at 600 yards.

thanks for your time.

 

[memilanuk]

What you *need* is a tight grouping load, at distance. 2700fps will work OK w/ that, but more is always better... assuming accuracy is there. I'm chasing more speed, but not at the sacrifice of accuracy. Little groups, a tight hold, and learning to call the wind can make up for a bit of speed differential. At least for me. Others may disagree.

 

[Vulcan]

For what it is worth, I am working up loads for a 6br now. I have used form 29.5 of varget up to 32. With the 32, I am getting 2965 average velocity with a spread of 31 and a standard deviation of 8. Accuracy was good.

I am going up to 32.5 and try that and also try re-15 once I come up with a good load for varget.

I have a 1-8 twist 271/2 barrel so I would think the velocity should be about the same in your gun.

 

[mitchellchandler_au]

thanks guys,

I am hoping to get to the range today and try a few over the chronograph to see what they are doing. If the velocity is below 2750 I might try a larger charge and hope the accuracy doesnt fall off to badly.
Oh yeah, If you guys have any benchrest tips for me it would be a great help.

thanks again

 

[Aussie_bob]

Mitchell,
I take it you are here in Australia, Which Part?
I would only be sneaking the load up and see if accuracy gets better or worse and stop when the groups start to spread.
Speed isn`t everything if you have an accurate load you have a better chance of holding it together over distance than starting out with an inch group, it is only going to get worse.
If you do get to shoot over a chrony give me the speed and scope hight above centre of bore and i can tell you how many inches high at 100 yards you need to be to be on at 600 it works.
My first time shooting at 500m with my 30BR i was on paper with my first shot adjusted for more windage and was dropping them in the 9 and 10 rings.
Email me if you like will help anyway i can.

 

[mitchellchandler_au]

Hey bob, how ya going mate?

I live in NSW. I built the rifle on a rem700 and lilja barrel it has a aussie lami stock in the MBR profile
I tried the 6mm at 900 yards it worked out to be 28 MOA over the 100 yard zero it also works out to be about 3/4 the windage the fullbor shooters were using. I have wondered how the 30br would go in Fclass open competition. What do you think about it.
Thanks, mitchell

 

[Aussie_bob]

Mate i am in Nth Queensland and will be in Sydney 13th 14th 15th for the RBA at SISC. I have only shot my 30BR out past 300 yards twice once in Pratice FLY shoot then in the QLD FLY Peter Short Memorial where i took out the light gun, Smallest Group & highest score on a single target shot a 1.75 inch group at 500m would like to try it a bit further out as the ballistics programe tells me it will hold up so who knows.

 

[mitchellchandler_au]

i have finished graphing the velocities of my loads. i have chosen the 105 A max because it allows me to use 29.9 gn of varget to get 2870 ft\s against the 107 with 28.5. the A-MAX load puts 5 shots into .120-.200 all day long.