I have decided to build a 6mm br for varmint shooting on an accumark action I have. My bullets of choice would most likely be in the 60-70g weight and might try the some of the 55 and 58 g bullets and perhaps a 75g. But, 90% of its diet will consist of bullets in the 60-70g range.

What twist rate would be best for the above weights and will it stsbilze the 55’s or the 75’s? Should I go with a 26†or 28†tube? What velocities can I expect with bullets in the 60-70 weight range with a tube in the 26 -28 inch range? Is there anything that I should have done to the action to bring out all the accuracy potential it may have.

I was thinking of going with a Hart, Krieger or Shilen in that order.

Help me spend my money

If you never intend to shoot anything heavier than a 75gr bullet then a 1 in 13 twist will do just fine. I would go no longer than a 26" tube. And finally, Krieger, Krieger, Krieger.

Thanks 30378

What is your best guess on velocity. I am thinking about 3500.

I must agree that longer than 26" would be a waste, and 24 probably better for the case capacity you will be burning. Ditto for Krieger or any other premium barrel maker.
The real issue is in the proper chambering, and fit of the neck and throat. Have your gunsmith understand what bullet and overall cartridge length you want to use.

Anything can be pushed but you will safely get 3400 with 75s and 3500 with anything lighter.

Check out www.6mmbr.com

Thanks guys. I have been to 6mmbr.com. Its a great site with lots of information.

FJOLD,

I noticed that you are from Bakersfield. I was born and raised there. I currently live in colorado springs, I am a military transplant for the last ten years.

quote:

The real issue is in the proper chambering, and fit of the neck and throat. Have your gunsmith understand what bullet and overall cartridge length you want to use.

I am looking at the same thing.. my call would be to make the twist one in 14 or one in 12....

I was looking at 1 in 14... longest bullet being a 80 grain Nosler Ballistic tip...

I second what Mr. 308Sako said.. I always make a dummy round of the longest bullet I plan on shooting.. and when the action goes to the gunsmith for install of the barrel, I hand him a couple of dummy rounds and tell him to make sure that the barrel fits "these"...

You don't say what varmints or if you live in an area where you might be shooting when the temps. might be below 32 degress F.. If you are I would error on the side of slightly faster (12) due to the fact lower temps do affect bullet stability. Any of the barrel choices you mentioned are good, but if it was mine I would favor the Krieger as #1 choice, unless you are in a hurry to get the project going.


www.duanesguns.com

Just had a 6BR done........this was a 8.5:1 twist, 16" barrel XP-100.....fired bullet weights from light to heavy very well. r in s.

I just finished (as in last spring) re-barreling a 40XBR that was a tight neck 6MM BR from Remington's custom shop. It was a 1 in 14 twist which Remington claimed wouldn't stabilize anything over 80 grains. I can't attest to that because even with it's 27 inch barrel the velocity with the 70 grain Ballistic Tip only ran 3,380ish and as it's purpose was varminting I didn't want something even slower than that. It was extremely accurate and surprisingly it's favorite accuracy bullet wasn't a Cook or Berger or any of a number you'd expect it to be, it was the 70 grain Sierra MatchKing (mid .2's to low.3's).
That bullet wasn't much for rat smackage so the two I used for varminting were the 70 grain Ballistic Tip (upper .3's to low .4's) and and second most accurate and a lot cheaper was the Hornady 70 grain SX it really came unwrapped even at the slower velocity (of course that's what it's designed to do, mid .4's to low .5's).
I tried the lighter 6MM bullets like the 55 grain BT when they came out but while faster and explosive up close the 70 BT with it's much better BC carried out better especially in the wind.
If I were to build a 6 BR today after what my experiences were with mine I'd have it improved to the 6mm Dasher with the shoulders blown out to 40 degrees for a little more ummph. More likely I'd do a .243 or .243AI with a tight neck in a 26inch 1 in 12 for some real sizzle with 70 to 85 grainers.
That's just for my personal use which involves a lot of medium long rangers and usually wind, also I don't compete, it's all varmints. Don't get me wrong, the 6BR is a great round and mine was the most consistently accurate, non-custom made (as in I just called and found it on a shelf) rifle I've ever had. Maybe mine had a particularly slow barrel but if I wanted decent case life 3,380ish with a 70 was about it and I found that kind of a yawn after a while. Sorry for rambling.

It really all depends on what the use will be and how far the shots will be. I built a 6mmbr for range work and hopefully a 500-600 pdog rifle. I chose 1-8 twist with the intentions of shooting 90 berger match, 95 berger vlds and 105 amax. I had it throated with enough freebore so that the longest bullet would give me sufficient jam and still stay in the neck to prevent the doughnut problem. I just started shooting it a few weeks ago and it seems to shoot the 90 bergers real well and 87 vmax almost as good.

If you need something that will reliably feed from mag, you might want to look elsewhere. That fat short case doesn't seem to feed well in most rifles.

quote:

Originally posted by DuaneinND:
You don't say what varmints or if you live in an area where you might be shooting when the temps. might be below 32 degress F.. If you are I would error on the side of slightly faster (12) due to the fact lower temps do affect bullet stability. Any of the barrel choices you mentioned are good, but if it was mine I would favor the Krieger as #1 choice, unless you are in a hurry to get the project going.


www.duanesguns.com

yeah Duane,

Should we call that a No Dakota and NE Montana twist??? Hell freezing over doesn't get as cold as it does where you live, especially when you get one of those mild 40 to 50 mph breezes blowing across the prairie...

Let me start off by stating that the 6BR is my personal favorite round. I have had a couple of reamers and loved them all. I would recommendusing oneset up for the Lapua brass or none at all. Second,I you can swing a second barrel, have the reamer run in and spaced with a 22-250 go/no go. They feed a little smoother in the field, give you a little extra and are an absolute clast to shoot. Its kind of a 6BR long, or a 6/250 AI. I have alway slike my hart barrels, but the only prblem I see with a Krieger.... it just plan SHOOTS.

quote:

Originally posted by love22hunt:
I have decided to build a 6mm br for varmint shooting on an accumark action I have. My bullets of choice would most likely be in the 60-70g weight and might try the some of the 55 and 58 g bullets and perhaps a 75g. But, 90% of its diet will consist of bullets in the 60-70g range.



What twist rate would be best for the above weights and will it stsbilze the 55’s or the 75’s? Should I go with a 26†or 28†tube? What velocities can I expect with bullets in the 60-70 weight range with a tube in the 26 -28 inch range? Is there anything that I should have done to the action to bring out all the accuracy potential it may have.

I was thinking of going with a Hart, Krieger or Shilen in that order.

Help me spend my money

Why use a Weatherby Mark V it's fully an inch to long for a 6mm BR?

I flat love my 6BR. I had it built just for predator calling, especially night calling. I am running 65gr V Maxes pushed by 30gr H322. I built this gun on a Remington 700 SPS action and 24" Shilen SS match grade barrel with a magnum contour. Twist on it is 14. Accuracy on this gun is unbeleivable. What I really like is the V Max. I have yet to blow up a cat since it was built 2 years ago by Cecil Tucker in Odessa, Tx. I haven't chronoed the gun yet but it is a flat shooter. I have over shot a couple of coyotes when I first started shooting it around the 200 yard mark. Should have held dead on.

Bob

You have some good information, Sharing my thoughts as well. I have built sevaral 6BR rifles for benchrest shooting. When we started 600 yard benchrest shooting a 6BR became one of the top chamberings. After watching the guys use old take off 13 to 16 twist barrels, and the 7 to 10 twist new barrels; I find this. A 15 twist barrel will shoot a 60 to 75 grain bullet at 600 yards well. You can get speed and bullet holds with out blowing up. Have built 6BR rifles using 1 in 8 twist barrels. Result is the 8 twist will shoot from 60 grain bullets to 107. Accuracy of the light bullets at 100 to 300 yards is mind blowing. Speed is hindered a bit. I have a Shilen barrel with 1 in 15 twist finished at 26 inches. Was used to shoot a 1.25 group at 600 yards. Held reange record for 2 years. Is like new and owner decided to replace it with 1 in 8 twist. Heavy varmint taper. Threaded for a Stolle action with lotys left over for fit to any action you like. If you want a good varmint barrel with lots of life I can get a price for you. I have several others that came off. I do have an optical bore scope and would not sell anything with issues. Good luck and enjoy the shooting
55 Noslers in a 6br will take mr P. Dog apart.