[b]I’m looking to get a 6.8 upper 11.5" where can I find the complete upper at a decent price $500’s?
Also I heard that the 223 or 556 magazine can be used for 6.8 rnds and a normal 30 round mag of 223 will hold 24 or 25 rounds of 6.8?, and if they are used for both are there any short comings that would make doing so worth not doing? [/b]
6.8 does not function in 5.56 mags.
5 to 7 rounds is typically the most that you can fit into a 5.56 mag and expect it to function. Beyond those numbers, the mag walls swell and will not fit in the mag well. I believe that some people have been able to fully load some 5.56 mags- HK mags if I recall correctly. There is nothing cheap about the 6.8 cartridge. If you are serious about taking the 6.8 plunge, I would suggest you save up a little more coin and purchase a quality upper. The post above mine would be a good place to start.
Just get some 6.8 mags. Unless you reload 6.8 is $1/trigger pull. And even brass plus primers plus rounds plus h322 are still going to be $0.75/round. mags are the least of your cost.
ok makes sense
Well I have found a good price I have decided to go with a RRA 6.8 Car Complete Flat Top Upper with picananny gas block,
But my question is I want to cut this to 11.5 inches and then I want a 5.5 flash hider is there one to fit the thread size thats on this barrel or can I have the barrel threaded to accept 1/2 x28?. and with the twist rate it has is it sufficient enough or ideal for the 11.5 inch length I want?
6.8 SPC Rem Chamber SAAMI II—Forged A4 Upper Receiver—Chrome Moly 16" Wilson Barrel 1:10 Twist—CAR Handguard—A2 Flash Hider 5/8-24 Thread
part 2
What would be the Differnce in Performance between a 1/10 twist and 1/11 twist at 11.5" and 16" Barrel lengths using the 6.8 round?
5.56 mm muzzle devices no workie with 6.8 mm projectiles. Were you the kid in Kindergarden trying to make the square peg fit in the round hole?
The 6.8 typically uses the 5/8-24 thread as done.
Finally saw the CAR length gas, deleted remark.
From the shooters at 68forums, a difference in twist might make an incremental decrease in chamber pressure. On a 11" it may be so small it’s not detectable without lab equipment. The hunters looking for max velocity go with 11.5 or 12 inch rifling with the least lands possible, down to three. That pushes things up to 3000 fps - in 16" barrels.
What’s nice about the 6.8 is it’s reputation for keeping most of that at 11".
Finding the best ammo to shoot that guns sweet spot will be the fun part.
Thanks Guys got another question does anyone know if Rock River will be offering piston systems?, and would there really be a big help having one over the D I system.
And also thinking about getting the factory RR rail system will that make a significant difference as opposed to regular hanguards in dissipating heat?
Also has anybody tried Right2BearARms 6.8 Ammo, What do you think of it?
How Long are RRA 6.8 Car Hanguards ?, Does anyone know if the RRA Carbine Length Free Float Rail System will accept Adams Arm or Cmmg Carbine length Gas Piston Sytem w/o Modification?
CAR handguards are the shortest - and most AR builders are moving to midlength to have better gas dynamics. It’s not as hard on the internals as a carbine length sometimes turns out.
Moving to piston driven is problematic. There are some good companies going that route, even Remington introduced a new upper yesterday. None are discounted, all are proprietary, parts are hard to get. That means long waits for spares, and only at their price. The result is that you get a gun that doesn’t get quite as dirty as DI - but all guns get dirty.
Free float handguards are nice for the looks, mount a lot of equipment, and do prevent a sling from moving the barrel and point of impact. They seem to be about a 1/4 MOA improver. A better quality barrel will do as much. Disappating heat is variable - AR’s don’t really get hot unless a lot of mags are run through quickly. If you plan to shoot 4-5 mags continuously in a string of just a few minutes, there will probably be other problems over the long run. Regardless of the handguard, things will heat up.
Fit of various combinations of handguards, gas blocks, etc is a common question - but not that many have tried them all. It’s easier to get dimensions off websites and compare yourself. The vendor is the best source of info as they have tried most of them and received feedback from customers who’ve done things no one thought of before.
Check the SHOT 2010 threads for info on new products. Most makers hold off on announcements until the show, and they are usually the only ones with knowledge of their future plans. Since the invention of the internet, more are holding future products a lot more quiet. It seems that small groups of brand fanatics create difficulty with their complete lack of knowledge about product development and their repeated requests for instant gratification.
New products can take years to bring to the market, and it is a risk that the money spent will be lost in a resounding sales dud. The handgun market is full of examples. The new S&W .380 looks like one, too, but that’s my opinion of it’s looks.
Excellent Answer !!!, Thankyou