Why 6.8spc?
 

Well I started looking into 6.8spc when thinking about doing a new AR build but I have recently decided to go with a 300 fireball instead. Looking into loads and such I do not see why 6.8 spc exists. When looking at a "perfect" setup for the military why in gods name did they not think to mess with the 300 fireball (whisper) platform. I dont see anything that 6.8 does better than 5.56 that 300 does not do and better. 6.8 only has one bullet weight where with 300 you can go supersonic or subsonic. Finally, why would the military build something that needs a new upper when you can do the job better with just a barrel swap.

I am just not getting it, is there any reason to go with a 6.8?

I too have looked into the 6.8SPC and wondered why the 6.5 Grendel didn't win that contest. Both of these 6's give more energy at shorter ranges and the 6.5 gives a lot better terminal ballistics at ranges over 500 yards.

Both of these cartridges detriment was making ammo heavier, or the lack of use is probably the same reason why our military isn't using dragon skin armour.

Politics.

I have looked at the 300 Whisper and can't justify its existance over the 7.62x39. With C-Products making reliable mags, it makes for cheap practice ammo, a higher velocity than the 300 Whisper and it too can be loaded down to sub-sonic velocities as well.

My personal choice was the 6x45. Again just a barrelswap.
6mm projectiles from 40 to 107grains and velocities higher than the same bullet weight in the parent 223 cartridge.

For longer range work I chose the 243WSSM.

What is everyone elses thoughts?

The 6,5 Grendel breaks bolts when loaded to pressures that give you the stated ballistics.


You are absolutly correct... it is about the number of rounds/lbs.



The C-Products mags are not that reliable. I do agree that the 7.62x39 is an intresting cartridge, just as the 30 Rem. is an intresting cartridge.

If the 6.5 Grendel or the 6.8 SPC were going to break into military use the had to be able to use the same bolt and mags! (By the way shooting a Beta-C mag is very cool). Also if you want to see what really killed off the 6.5 Grendel or the 6.8 SPC military asperations look at the Sierra or Hornaday catalogue and look at the new .22 caliber heavy weights:

77 gr HPBT also called the open tip match bullet
80 gr HPBT
90 gr HPBT

One might have some problems with the 80 and 90 pills... but I think you get my point. These bullets shoot nearly as flat and hit as hard as the ~90 gr bullets out of the 6.5 Grendel or the 6.8 SPC.

320pf

YEs it probably wouldnt take much R&D to figure out a way to make 90grn 5.56 feed reliably. At least not the $$$ the army would spend replacing uppers.

reinforcements
 

I do not mean to direct people away from this site, but these is quite a discussion going on at AR25.com. It would be nice to get some more 300 whisper views represented there. The group there is VERY 6.8 SPC focused.

Here is the link
(AR-15 » AR Variants » Why 6.8 when 300 whisper is available.)

http://www.ar15.com/forums/topic.htm...f=121&t=351653

By the way kogashuko started this by asking the same question on the ar15.com site

320pf

old post but still very UNTRUE on several levels. the 6.5 grendel is NOT breaking bolts.BUT IT IS still in operation in MANY places of action in our armed forces hands ( Afghanistan is seeing how effective it is vaporizing camel jockeys at 1000 yards as we speak!) now try getting the 80 and 90 grain bullets out of a .223 to shoot 600+ while still staying SUPERSONIC! do the math, it wont happen with them. IT WILL with the grendel.

WOW, I didn't realize that the Grendel was in Afghanistan. What's the NSN for the the ammo and rifles? :bangin:

Kevin

Run the 6.8 brass through a 30 Herret die and you get something considerably more useful when coupled with the right barrel twist.:wink:

Too easy. It happens all the time with 77 and 80 gn bullets.

Afghanistan is the last place I would want to be with an oddball caliber like the Grendel. Getting ammo and spare parts could prove tough. When I was there it isnt like walking down the street and picking them up at the 7-11. If you want 9x19, 5.56 or 7.62 it is easy. 300 WM, 338 Lapua and 50 is hard enough.

Did the Math.


Name: 5.56
Ballistic Coeff: 0.362
Bullet Weight: 77
Velocity: 2650
Target Distance: 200
Scope Height: 1.500
Temperature: 70
Altitude: 1000

Ballistic Data
~~~~~~~~~~~~~~~
Range Elevation Velocity
0 yds -1.50 in 2650 fps
25 yds -0.07 in 2592 fps
50 yds 1.04 in 2534 fps
75 yds 1.81 in 2478 fps
100 yds 2.24 in 2422 fps
125 yds 2.29 in 2366 fps
150 yds 1.95 in 2312 fps
175 yds 1.19 in 2258 fps
200 yds -0.00 in 2205 fps
225 yds -1.63 in 2152 fps
250 yds -3.73 in 2101 fps
275 yds -6.30 in 2050 fps
300 yds -9.46 in 2000 fps
325 yds -12.96 in 1949 fps
350 yds -17.10 in 1900 fps
375 yds -21.90 in 1852 fps
400 yds -27.38 in 1805 fps
425 yds -33.57 in 1759 fps
450 yds -40.49 in 1714 fps
475 yds -48.14 in 1670 fps
500 yds -56.55 in 1626 fps
525 yds -65.73 in 1584 fps
550 yds -75.68 in 1542 fps
575 yds -86.42 in 1501 fps
600 yds -98.44 in 1462 fps
625 yds -111.41 in 1424 fps
650 yds -125.57 in 1387 fps
675 yds -140.94 in 1352 fps
700 yds -157.49 in 1318 fps
725 yds -175.23 in 1286 fps
750 yds -194.15 in 1254 fps
775 yds -214.72 in 1225 fps
800 yds -236.79 in 1197 fps