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View Full Version : 6mm BR twist rate?


WaltherP99
09-09-2009, 06:22 PM
I have been racking my brain with this question since yesterday and I just can't make up my mind! What twist?

First, Bullets I am going to be using will be 87gr. V-Max's, 90gr. Scenar's, 95 VLD's and 95 BIB's being the primaries BUT I don't wanna rule out the 105 A-Max's and the 105 VLD's. I also wanna keep my options open on distances (100, 300, 600 and possibly 1000) but I can see it getting more use out to at least 600!

Will a 1 in 8" do what I need it to do? I was thinking 1 in 10".

Opinions?

Also, will the 105's be stabilized at 100 in a 1 in 8" to show the true potential?
sinman
09-09-2009, 07:38 PM
You will probably want to go with the 1/8" twist because of the 105. I shoot 87gr hps out of my 1/8" with no problem.
tiny68
09-09-2009, 09:39 PM
Sinman is right. You can't shoot the 105/107s in a 1:10. Most 1:9s can't do it at the speeds a 6BR can produce. I have a new 1:10 6BR Krieger that shoots the 80 and 90 Bergers well. It also does do with the 95 BIBs. My newest 6BR is a 1:8. It is pretty amazing with the 107 SMK right at 3000 fps. That is a pretty good combo for shooting out to 1000 yds. However, I shoot some decent groups with 80 Bergers and VV N-133. If you want to go distance, you have to get the 1:8 twist. However, you might be happier getting a 1:8 now and then get a 1:10 or 1:12 when funds allow for shorter range stuff. Luck in your choice, tiny
pdog06
09-09-2009, 10:31 PM
My McGowen 8twist 6br shoots the 87gr vmaxes very well. Here's my best group to date, but most every load with them has been under 1/2 moa:

http://i158.photobucket.com/albums/t106/pdog06_photos/DSCN4175.jpg


I did try some 105 amaxes and they shot OK, but it was windy when I tried them and I havent tried anymore yet. I'm sure they can do better.

I'd go with the 8 twist just so you can shoot the heavier ones if you wanna.
WaltherP99
09-10-2009, 06:22 PM
Looks and sounds like the 1 in 8" is the way to go!

Thanks for the info guys!

Any of you guys shoot the factory stuff with the 90gr. Scenar's in you 1 in 8's? I'd like to know how that stuff would shoot in case I cant get reloads. (I have a gent who does my reloading for me, in case you are wondering.)
Dennis
09-11-2009, 04:08 PM
Is the 6br a 1000 yd gun?
WaltherP99
09-11-2009, 04:32 PM
Is the 6br a 1000 yd gun?


If you are referring to me...

I may use it for 1000...not quite sure! At least 600. Most of it's use will be 100-300 though. Which is why I was wondering if the heavier bullets will group well at short distances. I've read that some have trouble with them settling down at short distance.
Dennis
09-11-2009, 04:58 PM
No, It is a general question to all. I was just wondering if the 6br is a 1000yd rifle!
sinman
09-11-2009, 05:40 PM
It can be
WaltherP99
09-11-2009, 05:40 PM
No, It is a general question to all. I was just wondering if the 6br is a 1000yd rifle!


Ok...sorry! I read it wrong!
Armed in Utah
09-22-2009, 12:06 AM
It can be


With the correct action/barrel/optics/loads and shooter or course...
The 6BR will work......but of course there are beter choices.......
Cycler
09-24-2009, 12:31 PM
My newest 6BR is a 1:8. It is pretty amazing with the 107 SMK right at 3000 fps.
How you get 3000 fps with 107 gr bullets out of a 6BR when most .243 Win. struggle to get 3000 fps with 100 gr bullets. The 6BR is a much smaller case so how is it done? Extremely high pressure? Very long barrels?
tiny68
09-24-2009, 01:35 PM
My newest 6BR is a 1:8. It is pretty amazing with the 107 SMK right at 3000 fps.
How you get 3000 fps with 107 gr bullets out of a 6BR when most .243 Win. struggle to get 3000 fps with 100 gr bullets. The 6BR is a much smaller case so how is it done? Extremely high pressure? Very long barrels?


It is all about efficiency. Yes it is true, my 28" 1:8 twist 6BR Shilen will push the 107 SMK to 3000 fps with RE-15 and RE-17. And yes, it does it with 10 grams less powder than a 243 or a 6mm Rem (25% less). I have to hammer my 6mm Rem to get 3000 fps with a 107 SMK, to the point a ruin the brass is 3-4 firings. That is the wonder of the short fat little BR case. The 30BR is even more efficient. It can drive a 125 gr bullet to 3000 fps with 33.0 gr of H4198. I can get 150 SMK to 2600 fps. That is darn close to a 308 performance. And yes, the BR cases run at much higher pressures. The Laupa brass can handle it.

Luck, tiny