CMMG Endeavor 6.5 Creedmoor: From Unboxing to 1000 Yards

It’s always fun to try something new and different. And that’s exactly what I’ll cover in this article! I’ve shot AR-10s chambered for 308 Winchester many times, but haven’t yet shot a 6.5 Creedmoor AR-10, until now that is!

CMMG Endeavor 300-Series 6.5 Creedmoor AR-10

CMMG is best known for their AR conversion kits (22LR), Banshee AR pistols, and Resolute AR Carbines. The CMMG Endeavor lineup is a bit of a departure for CMMG, and is focused on long-range precision. CMMG has implemented their same attention to detail, multiple trim level options, and lifetime warranty with Endeavor (just like with Banshee and Resolute).

From the CMMG Product Page:

For shooters and hunters who need to reach out to extended ranges, CMMG’s ENDEAVOR is built to maximize long-distance precision. This lineup features all your favorite long-range calibers, with a variety of barrel lengths, furniture and high-performance triggers to maximize your marksmanship. Explore the ENDEAVOR 100, ENDEAVOR 200 and ENDEAVOR 300 series to find out which configuration is best suited for your long-range needs.


CALIBER: 6.5 Creedmoor
BARREL: 24” 1:8 Twist, 6.5 Creedmoor, Heavy Taper 416SS, SBN
MUZZLE: CMMG SV Brake, threaded 5/8-24
RECEIVER: Billet 7075-T6 AL upper, Billet 7075-T6 AL Lower
HAND GUARD: CMMG RML15 M-Lok hand guard
FINISH: Cerakote Standard
TRIGGER: Geissele Automatics SSA 2-Stage
TRIGGER GUARD: Integrated Into Lower
MAGAZINE: 20rd Magpul PMAG (LR-308)
WEIGHT: 11lbs 5oz(unloaded)
LENGTH: 45.2″

What’s In the Box

The CMMG Endeavor 300 6.5 Creedmoor comes with everything you need to start shooting except an optic, optional bipod (you can shoot with a front bag), and ammunition.

Above you can see what’s included, right after we pulled everything out of the box:

  • Lower assembly
  • Upper assembly
  • Instruction booklet and literature
  • (1) PMAG 20 20-round magazine
  • Slip 2000 lubricant (sample size)

Accessorizing and Preparing the Rifle

With the goal to go straight from 100 yards to 1000 yards, I wanted to make sure we setup the rifle properly, and this time I wanted to put an ARCA rail on this AR-10 so that we could use the Warne Skyline bipod which has an integrated ARCA mount.

Fortunately, the Endeavor comes with an M-LOK handguard, and I had an M-LOK ARCA rail, so things went together smoothly. Then it was time to install the optic!

Above: Nikon Black 1-Piece Cantilever 30mm mount (MSR height) and  Nikon FX1000 6-24x50mm First-Focal Plane scope with zero stop- a great setup for a long-range AR!

100 Yard Quick Sight-In

This had to be one of the quickest sight-in jobs I’ve done to date! I did a boresight (look down bore, adjust windage/elevation until reticle and bore view agree) and after that my first shot was on the 8.5″x11″ paper target! I was only about 4″ off the target spot, so with ShotMarker, it was a quick matter to get things locked-in. In 10 minutes, I had the rifle zero-d, the turrets zero-d, and the zero stop set- BOOM!

Getting On Target at 1000 Yards

For this shooting session, I used the Shooter App. I entered the rifle specifics and the ammo specifics (including velocity and BC for bullet) which yielded the following dope for 970 yards:

With our rifle ready to go, and dope calculated for our target, it was time to head up the hill to the 1000 yard firing line. The plan was to use ShotMarker (setup with solar power at 1000 yards) to validate dope, and get on target at 1000 yards (966 from where we were shooting that day), and then move over to the steel target.

Above: ShotMarker setup installed at 1000 yards (solar panel has been installed since this picture).

When I shot my first shot, I didn’t see anything on ShotMarker virtual target, so I opened up the ShotMarker sensor monitor which showed that my shot was LOW. Hmmmm…. that’s strange I thought! Here’s what things looked like once I got on target (after an initial bring-up):

You can see behind the sensor monitor that the shot is now visible on the target, and I had a 1″ grid on the ShotMarker virtual target to estimate my offset with. In the end, I had to come up an additional MIL (8.5 up instead of 7.5). Even after entering the weather/altitude data things were still almost a MIL off. It could be that our bullet BC wasn’t accurate, or we could have improperly estimated the muzzle velocity (muzzle velocity was at 100 yards, so I had to add about 120fps to my numbers from 100 yard sight-in). In any case, we were able to quickly get a 1000 yard come-up.

Then it was time to try and hit the 10″ x 10″ (taller with IPSC extension) steel target. The first shot was within about 2″ of center (see above). Now that’s what I’m talking about! With some variable wind I was on and off the target intermittently, but was able to place 3 in a row on the target, as seen in the video.

All three shooters took turns, and we ended up placing quite a few shots very accurately for elevation. You can see on the steel target inset (drone view) above how we had windage deflection due to the variable side wind. Overall a GREAT 1000 yard range day. I’ll be moving this target so what we get a true 1000 yards (needs to move back 30 yards total) at a later date.

Here’s what was truly amazing: We used factory ammo, an AR-10 rifle, and had an SD of 3.5 for velocity for 5 shots at 1000 yards. On this ShotMarker snapshot there is a large group size (34.7″) because this was the “get on target” string of shots:


Federal Factory Ammo: Gold Medal Berger 130 grain Match

For all of the shooting in this story we used the same factory ammunition: Federal Premium Gold Medal Berger 130 grain 6.5 Creedmoor. I was very happy with how this ammunition shot, and was surprised by the SD of 3.5 FPS for one of the 5-shot strings (see previous section).

I’m now curious what kind of groups this ammunition would be capable of with this rifle. For this story I specifically avoided shooting groups because I was very curious about “going straight to 1000 yards”, and not obsessing at 100 yards. While this worked out, I still need to investigate why my dope calculation was so far off (about 13% for elevation). I’ll have to figure that one out!

What’s Next

There are two things I’m looking to do with this rifle next:

  1. Shoot suppressed (muzzle is threaded 5/8 x 24)
  2. Do more testing and test hand loads

What do you all think of this rifle, scope, and ammunition? Please leave a comment! I can’t wait to do more shooting with this setup.

If you want to get your own CMMG Endeavor 6.5 Creedmoor AR-10, check out the product page at CMMG.

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One thought on “CMMG Endeavor 6.5 Creedmoor: From Unboxing to 1000 Yards”

  1. You are probably my favorite “real world” blogger-always good info and informative subject matter.

    I built a 6.5 CM AR-10 a couple years ago-its a mutt built with no two parts from the same manufacturer. Two most important parts are the Criterion barrel and the Geisselle SSA-E .

    Sure was satisfying to hit steel with it at 1250 yards-I was using my reloads though.

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