Part 2: A Hunting Rifle for the 21st Century in 6.8 mm Remington SPC

The loads mentioned in this article are safe in my particular rifle, but should not be used without first reducing the load in your rifle, and working up to maximum loads.  Check your loading data against a reliable source before attempting to work up a load.

                In Part 1 of this article, I described the new hunting rifle that I built in 6.8 Remington using the AR-15 platform, and promised to write a follow up article once I had gotten some more experience with the rifle, particularly its effectiveness on game.  I also told you in that original article that LSA President, Dan Zelenka had also built a new hunting rifle in 6.8 Remington using the AR-15 platform, but that he had taken a very different approach to his hunting rifle.

 

My rifle (top) and Dan's rifle (bottom) demonstrate the versatility of the AR-15 component system.  Dan's rifle was built on a carbine-length barrel that is free floated under the tube style hand guard.  The skeletonized buttstock also significantly reduces the weight of the rifle.

                I just got home from three days of hog hunting in Gonzales County, Texas, and now have some experience to report.  Dan has likewise taken game with his 6.8 Remington.  But, before we get into the performance of the round, let's first talk a bit about the two rifles.
 

                In the previous article, I described, in detail, how I built my rifle.  Briefly, I built my 6.8 Remington rifle around a Bison Armory stainless steel 20 inch barrel, with an SPR fluted profile and rifle length gas system in 1" in 11" (1:11) twist with a black Cerakote finish.  The barrel weighs 2.4 pounds.  I also equipped the rifle with fancy walnut furniture, which, by the way, I deeply regretted as I was stalking pigs over about 6 miles of walking.  The walnut furniture sure looks good, but it added a lot of weight to the rifle making it a much better stand rifle than still hunting rifle.  My rifle with a Leupold Rifleman 3-9X40 mm scope attached weighs 10.7 pounds.

                Dan's much lighter rifle is far better for stalking and still hunting.  His rifle was built around a Palmetto State Armory stainless steel 18 inch light profile, 6.8 SPC II chambered 1:11 twist barrel with a graphite black Cerakote finish weighing in at a spritely 1.75 pounds. In keeping with his goal of building a light weight carbine, Dan installed a Clark Custom Guns carbon fiber free float handguard and an Ace skeleton ARFX buttstock. The overall weight of his rifle with a Nikon 3-9X40 mm scope in a Burris P.E.P.R. mount is only 7.2 pounds. Although light, the rifle is capable of extremely good accuracy and leaves nothing on the table concerning effectiveness on game.  If you are considering building a lightweight, stalking rifle, this is the way to go.

6.8 Remington Loads Developed for Hunting Hogs and Deer  Bullet Powder Charge Weight (Gr) Muzzle Velocity (FPS) Group Size (in) Jay's Rifle Group Size (in) Dan's Rifle 95 Gr Barnes TTSX RL-10X 29.5 2675 ± 09 0.25 110 Gr Nosler AccuBond A2200 26.9 2553 ± 21 0.16 27.5 2599 ± 14 0.29 28.0 2628 ± 11 0.22 28.6 2706 ± 14 0.10 Dan's load (95 Gr Barnes TTSX)  used Silver State Armory (SSA) brass and CCI 450 primers.  Jay's loads (110 Gr Nosler AccuBond) used SSA brass and Remington 7½ primers.

Itemized List and Associated Costs for Dan's Rifle Item Supplier  Cost Barrel, lower parts kit, upper parts kit and gas block Palmetto state Armory  $    336.24 Bolt carrier and butt stock PK Firearms  $    210.00 Trigger (Geisselle SSA-E) White Oak Armament  $    210.00 Fore end Clark's Custom Guns  $    105.00 Gas tube White Oak Armament  $       15.00 Magazines (2) Brownell's  $       86.00 Crush washer  $         3.00 Cerakote finish  Ritten Precision  $       40.00 Upper and lower receivers  $    225.00 Cost to assemble  $    100.00  $ 1,330.24

                After considerable research by Dan, and discussions between the two of us, Dan and I decided that the Barnes 95 Gr. Tipped Triple Shock (TTSX) bullet would yield the ideal trajectory along with outstanding terminal performance on game.  Both Dan and I independently worked up loads with this bullet.  While Dan's rifle loved the Barnes 95 Gr. TTSX, my rifle hated it.  In the previous article, I covered in great detail my attempted loads with that bullet, and I'm sorry to report that continued load development resulted in me abandoning the bullet.  It is not at all clear why his 6.8 SPC II chambered barrel with a 1:11 twist likes the bullet, whereas my 6.8 SPC II chambered barrel with a 1:11 twist hates the bullet.

Accuracy is excellent from Dan's rifle with the Barnes 95 G. TTSX.

 

                Dan suggested that I try the Nosler 110 Gr. AccuBond bullet, as he had heard good reports of terminal performance with this bullet from other hunters.  Luckily, my rifle took to this bullet, and typically put the first two shots from the rifle into the same hole, with the third shot falling about one inch from the two-shot group.  This pattern is of note, as I previously had not paid any attention to the placement of each shot in the previous groups.  It is certainly possible that my rifle patterned the same way with the Barnes 95 Gr. TTSX bullets.  Because the barrel on my rifle is not free floated (unlike the barrel on Dan's rifle), the heating of the barrel after two shots may move the point of impact resulting in larger 3-, 4-, or 5-shot groups.  Interestingly, Dan's rifle did not shoot well with the 110 Gr. AccuBond bullets.

                The Barnes TTSX and the Nosler AccuBond are two very different hunting bullets.  The newer design of the TTSX bullet is based on Barnes' original TSX bullet. In 2003 Barnes introduced the triple shock (TSX) bullet.  Following feedback from hunters, Barnes improved the TSX by adding a streamlined polymer tip, resulting in the Tipped TSX.  The bullet has a 100% copper body with multiple rings cut into the shank. The added polymer tip boosts ballistic coefficient and improves long-range ballistics. The tip and a nose cavity of the bullet provide even faster expansion than was realized from the original TXS design. Terminal performance boasts complete penetration, near 100% weight retention, and four razor-sharp cutting petals that double bullet diameter.  The TTSX creates tremendous internal damage from instant expansion, deep penetration, and quick kills.

                Released in 2001, Nosler’s AccuBond bonded core bullets deliver expansion and penetration with outstanding weight retention at all normal hunting velocities and ranges. The tapered, highly concentric bullet jacket is constructed from gilding metal that produces minimal fouling compared to most bonded core bullets that use pure copper jackets. The jacket is bonded to a lead alloy core that is engineered for balanced expansion. The bonding process eliminates component separation, resulting in 60-70% weight retention.  The AccuBond bullet features a white polymer tip that prevents deformation in the magazine, boosts aerodynamic efficiency, and initiates expansion. This bullet also features a precisely formed boat tail that serves to reduce drag and provide a more efficient flight profile for higher retained energy at long range.
 

                Dan drew first blood with his new rifle on a nice, big bodied doe that weighed 140 pounds.  The doe was hit in the left chest by the 95 Gr. TTSX at 162 yards, and dropped in her tracks.  With a muzzle velocity of 2675 FPS, the bullet was traveling at 2193 FPS when it hit the doe with 1014 ft-lbs of energy.  The bullet entered through the left chest, nicked the spine, and then exited on through the right chest.  The impact with the spine certainly contributed to the deer dropping in its tracks.  Damage to the right chest area was dramatic, testifying to the rapid expansion of the TTSX bullet.

The 95 Gr. TTSX entered the chest on the left side, hit the bottom of the spine, and exited through the right chest wall.  The damage to the off-side ribs is significant.

Barnes 95 Gr TTSX Nosler 110 Gr AccuBond Range Velocity Energy Trajectory Velocity Energy Trajectory (yds) (FPS) (ft-lb) (in) (FPS) (ft-lb) (in) 0 2675 1509 -1.5 2706 1788 -1.5 50 2520 1340 -0.07 2582 1629 -0.1 100 2371 1185 0 2462 1481 0 150 2226 1046 -1.48 2346 1344 -1.34 200 2087 919 -4.72 2232 1217 -4.25 250 1953 805 -9.96 2122 1099 -8.91 300 1825 702 -17.48 2014 991 -15.51 350 1910 891 -24.25 400 1810 800 -35.37

                I took a nice 80 pound boar on my recent hunt in Texas.  The shot was made from the standing position at 60 yards while the pig was staring straight at me. Although I was aiming for a head shot, I missed slightly to the left, causing the bullet to enter on the right side of the chest through the protective cartilage shield near the hog's throat.  The extreme angle of the bullet caused the bullet to hit the spine, and exit well back on the right side through the ribs.  Like Dan's doe, the pig dropped in its tracks probably as a result of the bullet impacting the spine.  With a muzzle velocity of 2706 FPS, the bullet hit the pig at 2558 FPS with 1598 ft-lbs of energy.  There was less apparent damage to the off-side ribs, but the size of the exit hole left no doubt that the bullet had expanded and had plenty of retained weight.
 

The 110 Gr. AccuBond entered the chest on the right side near the throat, hit the bottom of the spine, and exited on the extreme left rear of the rib cage.  The large exit wound can be observed on the outside of the ribcage.

                Dan and I are both thrilled with the performance of our rifles to date.  Neither of us has taken any long shots on game, although the 6.8 Remington should be effective on light skinned game out to around 300-400 yards, depending on the load.  Assuming that a bullet needs at least 1800 FPS of retained velocity to expand, Dan's load with the 95 Gr. TTSX will be effective out to 300 yards, although there is significant bullet drop for a rifle sighted in at 100 yards (Dan's rifle is not sighted in for 100 yards).  My load with the 110 Gr. AccuBond will be effective out to 400 yards.  These figures notwithstanding, neither Dan nor I are very unlikely to put ourselves into hunting situations where a shot that far is likely with these rifles.  Both of us simply have too many tack drivers with much more energy that are the correct choice for long distance hunting shots.

Bullet Powder Charge Weight (Gr) 85 Gr Barnes TSX FB A2200 31.0 RL-7 29.0 H4198 28.5 95 Gr Barnes TTSX A2200 30.0 H335 30.5 100 Gr Nosler AccuBond A2200 29.6 110 Gr Hornady HPBT A2200 28.6 H322 29.2 H335 30.5 RL-10X 29.2 110 Gr Sierra ProHunter A2200 28.6 H322 29.2 H335 30.5 RL-10X 29.2 From Bruce Record, who has a 6.8 Rem with 1:10 twist barrel

As a side note to this article, after LSA Member Bruce Record read the article he forwarded to me some of his pet loads for the 6.8 Remington.  Keep in mind that I have not shot these loads, so I cannot attest to their safety or accuracy.  Please be sure to consult a reloading manual before working with these, or any other loads.