6BR from AR Performance

I have the upper all put together with the exception of the forward assist and the ejection port cover. Little details. Here are some pics of it all together. I went with the Noveske handguard and a JP scope mount. I am happy with how it turned out. Now I am just waiting on the neck bushings and we can put a load together. It will go on my lower that is my favorite ever. It is a Seekins lower, Geissle trigger, Larue grip, and Magpul stock. The forged upper for this build doesn't mesh perfectly with the billet lower like my other Seekins upper but I still like the fit. Can't wait!!






 
A little more information on the 6BR. On the Hodgdon site the recipe I will start with is for H4198. I will start with 58gr Vmax. Looks like I will start with 26gr and the max is 28.5gr. At the max the velocity is 3454fps. I guess we will see how it actually goes for accuracy and velocity. 6mmbr.com has some loads with other powders that are getting velocities as high as 3600fps. The powder measures they are using are above those on the Hodgdon site. Not sure how long the barrel is or any of their other variables. I am excited to see how things go.

For reference my brothers recipe for his DPMS Sweet16 is 23.8gr of H4198 with 55gr Vmax. His velocity is around 3100fps.

The last balistic information I saw for a 6DTI (paper, not in person) was using 28gr of H4198 with 55gr bullets. This pushed the velocity to 3454fps. This was based upon a printout from his software with a 22" barrel. Maybe someone else has some real data to share.
 
I am very interested in your results. I have been thinking about building another AR but not sure what caliber I am interested in. This one certainly has my attention.
I am not interested in the current flavor of the week .300Blackout as I find it a little boring to say the least. I am more interested in something that I can use for more than punching paper.
I currently have a 16" 6.5 Grendel that I sometimes use for hunting. It's only pushing about 2450fps with 120s so I would like a little more velocity to reach out further.
 
Originally Posted By: Warboar_21I am very interested in your results. I have been thinking about building another AR but not sure what caliber I am interested in. This one certainly has my attention.
I am not interested in the current flavor of the week .300Blackout as I find it a little boring to say the least. I am more interested in something that I can use for more than punching paper.
I currently have a 16" 6.5 Grendel that I sometimes use for hunting. It's only pushing about 2450fps with 120s so I would like a little more velocity to reach out further.

I think the big issue in your case may be the barrel lenght. I am getting 2750 out of mine that is a 24" on the 264 LBC. The split betwen 16 and 24 at 20 ought to give you around 2600 or so. Apples to apples on bore size and velocites though is interesting. The 6 BR's are usuallyy shot in a bolt gun by the BR guys and can be loaded hotter that they can with an AR thanks to our ned for gas pressure management. The 6 DTI, 6WOA and the 6X6.8 from BHW are all pretty fast. The real world aplication of the 58 in the 6X6.8 shows 3550 or so with excellent results down range on paper and fur. I don't do Quick Load as I suspect the extrapoltaions in many instances and thanks to not being rich have no direct first hand experince with the other two.

The brass on the 6 BR is a tad more expensive than the 6.8 base of the 6 DTI, 6 WOA and 6X6.8. Bushing dies are the only way to fly on any of these hot rok guns if you want the ultimate accurcay, IMHO. That,unfortunately,eliminates the sharper shoulder, non-standard cases like the WOA and DTI for straight neck down avoiding fireforming without spending bunches of bucks for custom dies vs a one size fits all standard non-bushing design. Adjustable neck tension is certianly your friend no matter which way you go.

I really am lokoing forward to seeing how the 6 BR shakes out. I am sure the accurcay will be stellar but puublished velocites always seemed a tad low to me.

Greg

 
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