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Discussion Starter · #1 ·
I acquired a 6.8 upper (18" bbl, 1:11 twist) last November because I wanted something heavier than a .223 and lighter than 300 Blk. I chose the 6.8 because of the range of bullet weights and versatility of uses. I reload for all my guns and looked forward to working through some loads for this rifle as well. I have run into some "challenges" with this cartridge and hope to get some help from those with experience at this task. One thing I noticed is that no one except Accurate Arms appears to show any load data for 130 and 140 grain bullets. Hodgdon and Lyman stop after 115 grain. At least the info I have doesn't. Another concern is the small and large primer brass available. Together with the use of magnum primers. I usually have better success when using Remington match primers and normally only use magnum primers when I see evidence of ignition problems. I would appreciate any guidance on the use of magnum primers and whether small or large primers are an advantage or not. I've not considered this cartridge in a bolt action but I am curious if accuracy is as illusive as it seems to be with an AR platform.
 

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Welcome to the forum!

Stick to small primer, only Remington makes large primer, everyone else is small now. This cartridge is designed to use a max 120gr bullet at magazine length and any data beyond that must be from your own testing.

Many say to use only mag primers in autoloaders, I use Winchester small primers and have never had an issue. Rem 7 1/2 are good too.

Accuracy is not elusive with this round or necessarily the platform either, maybe one particular gun here and there, but not the AR15 as a whole. My gun shoots an honest sub MOA out to 500 meters.

But, if you wanted lighter than 300bo, why try to shoot 130-140gr bullets? Stick to 90-120gr and the 6.8 will be happy and treat you well.


-Alexander
 

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Also ditch the printed book data as a go to, look here for and drop charges by 10% and work up till you get what your looking for. Most data out there is very conservative even factory ammo is loaded hotter.
 

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Discussion Starter · #4 ·
Thanks for the info. I actually wasn't looking for a cartridge in the 130 / 140 grain range but found it curious that any information over 115 grains was very sparse. I have been using partial boxes of various weight bullets hoping to find that part of the desired combo and unfortunately 115 bullets are not easy to find (at least around here) even at retail. Widener's had a 250 rnd. box of Nosler Cust. Comp. for under $40.00 so I jumped on it. 130 grain bullets seem to be very plentiful so....
Hornady 110gr. V Max seem to do quite well as do Speer 100 gr. soft points.
Interesting thing about printed load data is even the same author suddenly lowers charges for apparently no reason. Lawyers!!
 

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130 grain bullets can be easily run in the 2550-2600 range in a 20" barrel with proper reloading.
I run the 130 Sierra PH with AR-COMP around 2600 from a 20" ARP Barrel but generally stick to 120 grain and under for general use.
As others have stated use the published data as a starting point, some of it is running 100fps slower with the same components and charge wieght from the sub par specs of the barrels they used compared to my 20" ARP barrel.
 

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Welcome aboard!
Yeah, that's the reason for lowering the loads in the books. They are based on an outdated 6.8 spec chamber. That IIRC only 2 companies make (ARP is good to go.). Most bullets used are from 85 to 120gr (Hornady SST). Any longer & you run into issues with Magazine allowable COAL (Berger 140gr is an exception.). Some here cut the front of the magazine to allow for longer COAL.
 
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