6mm BR with 1/14 twist
- Thread starter JohnJ
- Start date
AckleymanII
Gold $$ Contributor
Gene Harwood set a world Record with a 6 BR with a 14 twist shooting the 60's at 3700 fps using H335, it burns so clean you will not believe it with your own eyes.
I had a 14 twist that was only 21 1/2" long that I shot the 60's at 3550 with amazing accuracy, my load with that lot# of powder was 32.5g. You absolutely must use a primer with at thick cup such as a 7 1/2, CCI-450, or CCI-BR-4.
I have seen rifles that would shoot all the way to 33.5g of H335 and it is best to start off at 31.5g and work your way up, the accuracy will rock your world!
AA2230 is another really great powder for the lighter bullets, meters like water also!
I had a 14 twist that was only 21 1/2" long that I shot the 60's at 3550 with amazing accuracy, my load with that lot# of powder was 32.5g. You absolutely must use a primer with at thick cup such as a 7 1/2, CCI-450, or CCI-BR-4.
I have seen rifles that would shoot all the way to 33.5g of H335 and it is best to start off at 31.5g and work your way up, the accuracy will rock your world!
AA2230 is another really great powder for the lighter bullets, meters like water also!
I have only shot a 6mmBR once, and that was 12 days ago with 75 gr Vmax 300 - 3100 fps, 1 rotation in 14" twist.
The bullets were stable out to 50 yards [.3 moa average], but not to 100 yards [1.75 moa average, some keyholing]
That is a .935" bullet.
What does it all mean?
Your bullet should be shorter than .935" minus safety margin.
The bullets were stable out to 50 yards [.3 moa average], but not to 100 yards [1.75 moa average, some keyholing]
That is a .935" bullet.
What does it all mean?
Your bullet should be shorter than .935" minus safety margin.
With 68gr Barts Ultras I have had much better luck with H-322 and BL-C2. I can’t get H-335 to shoot worth a darn, even with hot loads.
I have been using H-322 for the 75gr V-maxes no stability problems with my 1-14 twist Pac-Nor 4 groove 24†bbl. but I am pushing them hard I know it’s over 3500 but don’t recall the exact figure ES is in the single digits. The 75gr V-max shoots so well with H-322 I haven’t tried anything else. The H-322 burns very clean at the pressures I’m running.
This is with a 6mmBR.
James
I have been using H-322 for the 75gr V-maxes no stability problems with my 1-14 twist Pac-Nor 4 groove 24†bbl. but I am pushing them hard I know it’s over 3500 but don’t recall the exact figure ES is in the single digits. The 75gr V-max shoots so well with H-322 I haven’t tried anything else. The H-322 burns very clean at the pressures I’m running.
This is with a 6mmBR.
James
Catshooter
The load I am using is 32.8 gr H-322 with BR-4 primers which is about 10% over Hodgdons maximum load. During load development my rifle stabilized the 75gr Vmax at 28gr,my starting load) so I am unsure why you aren't able to stabilize them, elevation here is around 2000ft, maybe my actual twist is a little faster than 14. I have not checked with a patch. I ordered a 14 twist and the shank was stamped 14 so I just assumed it to be correct. I have been sticking with the hot load because the rifle shoots well there and the powder burns cleaner and the primer pockets seem to be holding up ok.
James
The load I am using is 32.8 gr H-322 with BR-4 primers which is about 10% over Hodgdons maximum load. During load development my rifle stabilized the 75gr Vmax at 28gr,my starting load) so I am unsure why you aren't able to stabilize them, elevation here is around 2000ft, maybe my actual twist is a little faster than 14. I have not checked with a patch. I ordered a 14 twist and the shank was stamped 14 so I just assumed it to be correct. I have been sticking with the hot load because the rifle shoots well there and the powder burns cleaner and the primer pockets seem to be holding up ok.
James
Per my experiments, a 1 in 14" twist 243 barrel will stabilize a .935" long 75 gr Vmax bullet at 3000 fps out to 50 yards, but not to 100 yards.
What does it all mean?
The bullet must be shorter than .935", like a
.243, 85, Sierra SP 1520...... 0.910" long
.243, 70, Hornady SP 2410....0.793" long
.243, 80, Speer SP 1211.......0.880" long
What does it all mean?
The bullet must be shorter than .935", like a
.243, 85, Sierra SP 1520...... 0.910" long
.243, 70, Hornady SP 2410....0.793" long
.243, 80, Speer SP 1211.......0.880" long
My 6mmBR with a 1-14" twist shoots like a laser with 65 grn. Hornady V-Maxes with a stiff dose of 34.5 grn. Varget, CCI sm. rifle mag. primers 450. The same bullet does well with 31.0 grn. VV135 with Fed. match primers. For 68 grrainers, I drop the charge a little and they shoot almost as well as the 65's.
Chino69
Bear in mind these loads are safe in my rifle but there is no guarantee that they will be safe in yours. Reduce load for safety and work gradually up.
Chino69
Bear in mind these loads are safe in my rifle but there is no guarantee that they will be safe in yours. Reduce load for safety and work gradually up.
I read this and other similar posts and decided to make a spread sheet containing the dimensional data for the bullets that I have on hand. Attached is what I came up with.
The OAL was measured with a regular vernier caliper. The Ogive OAL was measured with a Stoney Point tool in the vernier caliper. The boat tails were also measured with the vernier, but there is some approximation in doing so. Even with this, the data will provide a good basis for comparison. Incidently, while measuring at least 6 each of the bullets listed I was impressed by the consistency of the Hornady and Sierra bullets. The Bergers varied in OAL quite a lot. Another interesting observation is that is that all Hornady V-Max bullets and the Sierra 60gr HPFB bullets shoot very well in my .244 Rem and my 6mmBR with a Hart 1:14" 21" barrel. The same has been found true in my buddies .243 Win. Looking at the dimensions, the 65 gr V-Max and 60 gr Sierra HPFB have a bearing surface length of .348 and .375, interesting. Many say to get the 75gr bullets to shoot well you have to push them to about 3300 fps. I have not tested this.
If anyone has additional data, I will ad it to the spread sheet and edit it here. Thanks, Peter.
There are 2 pages of info here. In Excel click on "sheet 1" and then "sheet 2".
The OAL was measured with a regular vernier caliper. The Ogive OAL was measured with a Stoney Point tool in the vernier caliper. The boat tails were also measured with the vernier, but there is some approximation in doing so. Even with this, the data will provide a good basis for comparison. Incidently, while measuring at least 6 each of the bullets listed I was impressed by the consistency of the Hornady and Sierra bullets. The Bergers varied in OAL quite a lot. Another interesting observation is that is that all Hornady V-Max bullets and the Sierra 60gr HPFB bullets shoot very well in my .244 Rem and my 6mmBR with a Hart 1:14" 21" barrel. The same has been found true in my buddies .243 Win. Looking at the dimensions, the 65 gr V-Max and 60 gr Sierra HPFB have a bearing surface length of .348 and .375, interesting. Many say to get the 75gr bullets to shoot well you have to push them to about 3300 fps. I have not tested this.
If anyone has additional data, I will ad it to the spread sheet and edit it here. Thanks, Peter.
There are 2 pages of info here. In Excel click on "sheet 1" and then "sheet 2".
Preacher
Gold $$ Contributor
Pinto-
if you ever get your hands on those 66 grain Fowlers, please let every one know, and then run right out and get a lottery ticket ASAP.
Maybe the kid finally woke up to the fact, that his Father made a heck of a 66 & 80 grain bullet, and if he gets it in gear he can possibly do the same...
I'm still waiting for conformation of my last order placed a year ago come June....
I couldn't get the bullet link to open on my new G-5 :,
if you ever get your hands on those 66 grain Fowlers, please let every one know, and then run right out and get a lottery ticket ASAP.
Maybe the kid finally woke up to the fact, that his Father made a heck of a 66 & 80 grain bullet, and if he gets it in gear he can possibly do the same...
I'm still waiting for conformation of my last order placed a year ago come June....
I couldn't get the bullet link to open on my new G-5 :,
Preacher, I ordered some Bart's 66 gr wedge bullets the other day. I have not yet received them. I can try to PM you the Excel document. If it does not work email me and I will send it direct. I have another sheet where I calculated how much of each of the bullets will be in the neck on my rifle. Even though it is specific to my rifle, you can see a trend for comparison. Take care, Peter.
I have had good luck with the 75gr vmax's out of my 1:14" Shilen 6mmBR barrel pushed by 32.8gr of varget. If i drop down to 32.0gr of varget it shrinks my group by roughly .1,from .327 to .224) at 100 yards. I have also tried 31.0gr of varget with stellar accuracy and no stabilization issues. I don't know the exact velocity of this load but i'd guess somewherein the 3200 FPS range in my 26" barrel. I don't seem to be having stabilization issues at ~55*F and 1200 feet in elevation. I have repeated these groups a couple of times so I'm pretty confident in saying they are legit. I'm using Lapua brass and BR-4 primers for what it's worth. I haven't tried these at 200 yards yet but I'm pretty sure they will be stable? Just give it a shot and see what happens.
Ruck
Ruck
Bobbyboy6br
Silver $$ Contributor
Great info on the 6 br I have a trued up rem 700 with a hart 1-14 t 22 inch barrel just wondering did you ever try using the Sierra 70 SBK or the 70 SMK bullets ? Thank you
Lone Hunter
Silver $$ Contributor
BB, Just a heads up. This thread is 11 yrs old. Don't know if you will get a reply from anyone. You might want to contact ackleyman as I know he is still active here. Good luck to you. I have a 1/8 twist and wondered about the lighter bullets in it.
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