Building a 6.5 Grendel for all purpose use
So...... I have decided to start building high end 6.5 Grendel rifles. As the military is looking for a replacement for the venerable 5.56 that has been in service so many years now, the 6.5 Grendel looks like a very appealing replacement. Over the past sixteen years of the Global War on Terror, one glaring draw back of the 5.56 caliber M4 has stood out. The round just cannot respond to the 7.62X39 fired from the Russian PKM machine gun. The max effective range of the PKM is around 800 meters, and when engaged from that distance, US soldiers on the ground must rely on their MK48 or M240B 7.62 machine to accurately engage the PKM fire. This is obviously a huge problem considering that there are relatively few 7.62 machine guns compared to the M4's or M16's that almost all soldiers carry on the battlefield.
I decided that if I am going to do this, I want to use only the best parts available for the rifle so that I can truly see what the capabilities of this round are. Some of the parts that I have used on my first build include a Wilson Combat matched forged receiver set, Geissele Mark IV 15in rail and Geissele SSA trigger, Lilja 19.1in stainless steel barrel, Seekins Precision lower receiver build kit, and a Luth-AR MBA-3 adjustable butt stock on a mil-spec buffer tube. I was expecting this rifle to be relatively heavy and I built it to be more of a long range gun (out to 800 meters) but in the end, it is not much heavier then any of the other AR's that are out there and a damn sight lighter then some.
BUILDING THE RIFLE:
Once I got all the parts for the build, I pre-fit everything to make sure there would not be any issues with assembly. This is where you appreciate buying quality parts. The parts I bought for this build are:
Wilson Combat Matched forged receiver set
Lilja stainless steel 19.1 inch mid length gas system barrel in 6.5 Grendel with matched bolt
Lilja stainless steel muzzle break cut from the same steel as the barrel
Geissele SSA trigger
Geissele Mark IV hand guard w/ Geissele gas block
Aero Precision Nickel boron bolt carrier
Seekins Precision lower receiver build kit
Luth-AR MBA-3 adjustable mil spec butt stock
Harris 6" adjustable bi-pod
The build was pretty straight forward with no real issues. The Wilson Combat receiver set was Cerakoted FDE and whoever they have doing there Cerakote does not skimp on the coating. That being said, the holes in the receiver had to be reamed out a little because I could not get the take down pins or the safe selector switch to move. A minor complaint really. The Lilja barrel fit very snug in the upper receiver but not so snug that it had to be forced in. Once the barrel was fit in to the receiver, the Geissele barrel nut was torqued to the recommended 40 ft lbs, and the after installing the gas block and gas tube, I slid the Mark IV hand guard over the barrel nut, which had a very precise and snug fit, lined it up with the rail on the upper and snugged down the two set screws and it looked fantastic. I can't say enough about this rail system from Geissele, it is really bomb proof. Next step was to assemble the lower receiver with the Geissele SSA trigger and finish it off with the Seekins Precision build kit, which is top notch and really makes the build look great. After that was done, I slid on the Luth-AR MBA-3 and got down behind the gun to adjust it to me. Like I said earlier, once it was all done I was amazed at how light the rifle actually was. I was excited to get it out to the range and see what it could do.
So I finally got it out the range to do a little shooting and see how this rifle is going to shoot. I set a target out at 50 yards just to make sure I was on paper and didn't have to chase rounds around the range all morning. After a few clicks of adjustment, I was able to move the target out to 100 yards and see how it grouped. I purchased two boxes of ammo (which is very limited currently) from Cabellas. Both boxes where Hornady. The first was 123 Grain SST and the second was their 123 VLD ammo.
After getting everything dialed in at the bench with the scope and the rest, I loaded up a couple of the 123 Grain SST's. The first 5 round group was disappointing and might have grouped at 2 MOA, but I think it was probably a little bit over that. I knew that the gun should shoot at least 1 MOA and realistically much better then that. I After shooting 4 five round groups and getting no better then 2 MOA, I switched to the 123 Grain VLD's and hoped that the change in ammo would also create a change in group size. As, I hoped, the new ammo did effect the group size.....and how! The VLD's printed at just over 1/2 MOA, and that was probably my inability to really shoot an AR as accurately as some other can. I came up with shooting bolt guns for long range accuracy and have never gotten comfortably with driving tacks behind an AR platform. But, none the less, the VLD's really got the job done. After cleaning the barrel, the first round had a point of impact approximately 1/4 inch from the rest of the group, which had all four rounds touching. Not bad for a gas gun at 100 yards. The word on the street is that the 6.5 Grendel really prefers 200 yards over the standard 100 yards that everyone like to zero at. Unfortunatly, I didn't have the time to move it out to 200 on this day and I am really looking forward to getting out and driving it a little further on the next range day. Stay tuned.
A little more shooting....
So after mounting a quality optic and zeroing the rifle, I headed back to the range to see what it is really capable of. I started out by putting the rounds through the chrony so I knew for sure how fast they were going and once I got the data I plugged it in to my Ballistic Calculator so I would know what adjustments to make on the scope. Next I took the target out to 200 meters to see what kind of groups I could get and was hoping for a minute of angle or better. Turns out, I got much better then that and had a few groups of 1/2 minute using 5 round strings. This is all with factory ammo, I haven't even started reloading fort his caliber yet.
Once I was confident that the rifle could hold those groups, I moved on to shooting steel at 600 yards. Since I forgot my steel silhouette target, I had to take a swing at the 12
inch triangles at the 600 yard line. After I checked my ballistic calculator and made the +67 click adjustment, I fired one round and it went high over the target. I put the reticle on the point of impact, and decided to make a 10 .01 mil rad click drop and the next round impacted smack dab in the middle. From there I fired 10 more shots and all of them impacted the steel. Not bad for 600 yards with an AR-15 rifle.
I'm looking forward to the next range session with this pretty exciting new rifle. Stay posted........