6.8 comparison chart------Information gathered from respective websites
Manufacturer	barrel twist	chrome/ CM	chamber/cone angle	Bolt	gas system length	muzzle thread	M4 ramps
DPMS	11x6	CM	SAAMI	commercial	carbine	1/2/--28	???
STAG	10x6tested	chrome	SPCII-HP-?	commercial	carbine	1/2--36	No
RRA	10x6	CM	SPCII-HP-?	commercial	mid	5/8--24	yes
CMMG	11x6	chrome	SPCII-HP-?	commercial	car/mid	5/8--24	Yes
Bushmaster	10x6	???	SAAMI	commercial	carbine	???	???
Yankee Hill	10x6	chrome	SPCII-HP-?	commercial	carbine	1/2--36	Yes
Model 1	9.5x6	CM	SAAMI	commercial	carbine	1/2--36	No
AR Performance	11.25x5R	nitro-carburized	6.8x43 HP-45 degree	9310 alloy	mid	5/8--24	Yes
AR Performance	11.25x5R	S Carb. Stainless	6.8x43 HP-45 degree	9310 alloy	mid	5/8--24	Yes

6.5 Grendel using Bill Alexanders max loads in a 16" barrel- zeroed at 200yds drops at 300yds.
due to energy being less than 1000ft lbs 300 yds is about max for taking deer or hogs with either caliber.
the same temp, pressure, line of sight and program used to figure all drops in both calibers.
100 Nosler-2600fps--drop 9.4/801 ft lbs
107 SMK-2545fps-----drop9.5/878ft lbs
123 SMK-2472fps----drop 9.4/1083ft lbs
120TSX-2472fps----drop9.8/984ft lbs

6.8 SPC SSA factory ammo 16" barrel
100 Nosler-2700fps--drop9.0/809ft lbs
110 Nosler-2630fps--drop9.0/939ft lbs
110TSX-2630fps---drop 9.5/856ft lbs ------added
6.8 handloads max
100 Nosler 2950fps---drop 7.4/993ftlbs
110 Nosler 2750fps--drop8.2/1040ftlbs

Available factory ammo

6.5 Grendel
Hornady-123 Amax
Wolf -120fmj
-------123 soft point
AA----120 Nosler
-------123 Lapua
-------129 SST
-------90gr TNT

6.8 SPC
BVAC-------110 Vmax
---------------115OTM
Corbon------110 TTSX
--------------115 SMK
--------------115 subsonic
DoubleTap--95TTSX
---------------110 Vmax
---------------115 FMJ
---------------110TTSX
---------------110 OTM
Hornady-----110 Vmax
---------------110 OTM
Hunting Shack-110 Vmax
---------------115 OTM
Rem.---------115 FMJ
---------------115 HPBT
--------------115 corelokt
--------------115SMK
Sellier&Bellot-110 TTSX
-----------------110 Vmax
SSA------------85 TSX------------SSAs loads available in Commercial and Tactical velocities
----------------90 TNT
----------------95 frangable
----------------97 AP
----------------100 Nosler Accubond
----------------110 Nosler Accubond
----------------110 Sierra Pro hunter
----------------110 TTSX
----------------115 SMK
-------------95gr Barnes TTSX coming soon