6.5 Patriot Combat Cartridge (6.5 PCC) Review

6.5mm AR-15 Wildcat

Forming the 6.5 Patriot Combat Cartridge (PCC) from virgin brass. From left to right: virgin 223 Remington case, case trimmed to length, case necked up to 6.5mm, loaded 6.5 PCC (pre fire form), fire formed 6.5 PCC case, and loaded, fire formed 6.5 PCC case.

6.5 Patriot Combat Cartridge (6.5 PCC) Review

I am a big fan of 6.5 mm (.264″) cartridges and the idea of a new 6.5mm wildcat for the AR15/M-16 quickly caught my attention.  Known as the 6.5 Patriot Combat Cartridge (6.5 PCC), it utilizes a 223 parent case and only requires the change of barrel and magazine in a standard AR-15/M16.  Existing 223/5.56mm AR15/M-16 parts are compatible with the design.  No new bolt or strange brass required.

AR-15/M16 cartridge line up (left to right): 223 Remington/5.56mm NATO, 6.5 PCC virgin brass, 6.5 PCC fire formed brass, 6.5 Grendel, 6.8 SPC, 300 AAC BLK, 7.62x40 WT and 30AR. Note the relatively short (.145") neck on the 6.5 PCC.

AR-15/M16 cartridge line up (left to right): 223 Remington/5.56mm NATO, 6.5 PCC virgin brass, 6.5 PCC fire formed brass, 6.5 Grendel, 6.8 SPC, 300 AAC BLK, 7.62×40 WT and 30AR. Note the relatively short (.145″) neck on the 6.5 PCC.

Illirian Engineering and Design created this cartridge.  They sell barrels, magazines and reloading dies for it. They were nice enough to lend me a 20″ stainless steel polygonal rifled barrel and Lee Reloading die set.

Developed as a 6.5 mm alternative for the AR15/M-16 platform, the 6.5 Patriot Combat Cartridge utilizes a 223 Remington parent case.  I used new Winchester 223 brass to form my 6.5 PCC cases.  I trimmed the cases to length, and necked them up to 6.5mm using the sizing die.  This initial batch was loaded and fired to form the brass to the chamber. During this process, known as fire forming, the brass expands against the chamber wall, increasing case capacity and changing the shoulder angle.

Forming the 6.5 Patriot Combat Cartridge (PCC) from virgin brass. From left to right: virgin 223 Remington case, case trimmed to length, case necked up to 6.5mm, loaded 6.5 PCC (pre fire form), fire formed 6.5 PCC case, and loaded, fire formed 6.5 PCC case.

Forming the 6.5 Patriot Combat Cartridge (PCC) from virgin brass. From left to right: virgin 223 Remington case, case trimmed to length, case necked up to 6.5mm, loaded 6.5 PCC (pre fire form), fire formed 6.5 PCC case, and loaded, fire formed 6.5 PCC case.

A World's Finest case trimmer (223 Remington) made short work of the initial brass trimming.

A World’s Finest case trimmer (223 Remington) made short work of the initial brass trimming.

Since I use a Forster press, the seater die needed to be modified.

Since I use a Forster press, the seater die needed to be modified.

A short piece of steel stock allowed the seater to work with my press.

Adding a short piece of steel stock allowed the seater to work with my press.

Since the case requires a decent amount of trimming, I used a World’s Finest 223 case trimmer to cut the brass to length.

In order to evaluate the new barrel, I built an upper receiver with the following parts from Brownells:

6.5 PCC upper receiver

6.5 PCC upper receiver

For testing and evaluation, I mounted a Trijicon USMC Rifle Combat Optic and Harris bipod on the upper.  My warhorse M4 lower with Geiselle SDC trigger completed the rifle.

6.5 PCC rifle as tested.

6.5 PCC rifle as tested.

Five round groups were fired for load development purposes.  Shooting was done from a bench with a rear bag.  A 2″ black dot was used as a target.  Velocity data was obtained with a MagnetoSpeed ballistic chronograph.  Target distance was 100 yards.  Results are posted below:

WARNING: The loads shown are for informational purposes only.  They are only safe in the rifle shown and may not be safe in yours.  Consult appropriate load manuals prior to developing your own handloads.  Rifleshooter.com and its authors, do not assume any responsibility, directly or indirectly for the safety of the readers attempting to follow any instructions or perform any of the tasks shown, or the use or misuse of any information contained herein, on this website.

6.5 PCC load development results- CCI 450 primer- Winchester brass- Presented for information purposes only.  Consult Illirian Engineering for data
Load # Bullet H335 (grains) Velocity feet-per-second SD Group size inches
1 Fire form 100 NBT 25.0 2357 9.1 1.036
2 100 NBT 27.0 2517 16.5 1.989
3 100 NBT 27.5 2540 10.6 1.581
4 100 NBT 28.0 2564 3.7 1.086
5 100 NBT 28.5 2589 17.2 2.072
6 100 NBT 28.8 2620 13.8 1.891
7 120 NBT 24.5 2140 27.2 1.418
8 120 NBT 25.0 2154 3.1  .779
9 120 NBT 25.5 2195 20.5 1.653
10 120 NBT 26.0 2227 13.6  .757
11 120 NPT 26.2 2254 19.1 1.259
Representative 100 yard group.  This one was fired on a QIT-99 head box during the zeroing process.

Representative 100 yard group. This one was fired on a QIT-99 head box during the zeroing process.

I tested the cartridge against Paul Howe’s CSAT standards.  These standards are shot using sights (no point shooting), with the rifle starting on safe with the muzzle below the belt.  Only clean hits in the scored area of the target count.  If any round misses, the drill is a failure.  I fired three different drills, 1-shot center mass, 2- shots center mass, and 5 shots center mass, one to the head.    I ran each drill five times and posted my average times below.

Drill # Range Description Average time (s)
1 7 yards Ready, fire 1  .75
2 7 yards Ready, fire 2  .81
3 7 yards Ready, fire 5 center mass, 1 to head 1.72

I selected the first drill for two reasons: I needed to warm-up and wanted to see if the combination of 20″ barrel and 13″ hand-guard would slow me down.  They didn’t.  The second and third drills helped me establish split times to see if the increased bullet mass would slow follow up shots.  Somewhat surprisingly, they didn’t.  My times with a 16″ 5.56 gun are remarkably similar.

I created this table to compare the 6.5 PCC’s muzzle energy with other 223 Remington based AR wildcats (I did take the liberty to include the 7.62×39 even though it has the 220 Russian as its parent case).   Results are posted below:

Muzzle Energy Comparison of AR-15/M16 Cartridges based on 223 Parent Cartridge
Cartridge Bullet Weight (grains) BBL (in) MV (fps) ME (ft lbs)
5.56 NATO FMJ 55 20 3306 1335.1
5.56 NATO FMJ 62 20 3097 1320.8
223 Rem BTHP 68 20 2740 1133.9
223 Rem BTHP 77 20 2796 1337.0
300 BLK OTM 125 16 2208 1353.5
300 BLK Accutip 125 16 2308 1478.9
300 BLK OTM 220 16 1090 580.5
7.62×40 WT NBT 125 18 2325 1500.8
7.62×40 WT TSSX 110 18 2447 1462.9
7.62×39 HP 123 16 2326 1478.0
6.5 PCC NBT 100 20 2620 1524.6
6.5 PCC NBT 120 20 2254 1354.1

The information presented above is based on data that I personally collected, no guessing, no box labels.  The barrel length varies depending on the cartridge, however, the table does provide a standard for comparison.

Note the 6.5 PCC 100 grain load provides the greatest muzzle energy in this data set.  Also note the 7.62x40WT/125 NBT (second place) was fired from an 18″ barrel.  In similar length barrels, the two cartridges would likely have similar muzzle energies.  The 6.5 mm 100 gain NBT has a sectional density of .205 while the .308 125 NBT has a lower sectional density of .188.  The cartridge with the greater sectional density should provide greater penetration on game.

Sample of .224″ (5.56mm) and .264″ (6.5mm) bullets. Left to right: .224″ 55-grain FMJ, .224″ 62-grain M855, .224″ 68-grain BTHP, .224″ 77-grain SMK, .264″ 100-grain NBT, and .264″ 120-grain NBT.

Sample of .224″ (5.56mm) and .264″ (6.5mm) bullets. Left to right: .224″ 55-grain FMJ, .224″ 62-grain M855, .224″ 68-grain BTHP, .224″ 77-grain SMK, .264″ 100-grain NBT, and .264″ 120-grain NBT.

What is the 6.5 PCC’s maximum point blank range?

The maximum point blank range (MPBR), allows a shooter to sight in his weapon at a given distance to hit a target of a given size when holding center mass.  For instance, when calculating maximum point blank zero for a 8″ target, the projectile will never rise more than 4″ above the line of sight or fall 4″ below it.  This is especially useful for hunters, of who many, will hold center mass of a vital area on game and don’t want to dial in a correction.  For comparison purposes, our calculations assume a 1.75″ sight over bore height (most AR-15s have a distance of ~2.6″ over the bore).

Maximum point blank range for the 6.5 PCC on an 8″ target is 284 yards.  17 yards shorter than a 16.5″ 223 Remington with Federal 55 grain FMJ (302 yards) and 29 yards longer than the 7.62×40 WT/125 NBT (255 yards).

How does the 6.5 PCC compare to the 6.5mm/TCU?

The 6.5m/TCU is a popular choice for use in the in silhouette competition.  Although I am not personally familiar with it, I was able to examine some 6.5mm/TCU data and compare a reamer print of a 6.5 PCC with a 6.5mm/TCU (Kiff, Gunsmith’s Book of Chamber Prints, page 357).  The TCU utilizes a 40 degree shoulder (PCC is 32 degrees) a case 1.749″ long (PCC 1.6450″), with a neck length of .255″ (PCC is .145″).  According to some old forum posts by the designer, it appears the PCC was the TCU optimized for the AR-15/M16 platform.

So what do you think of the 6.5 PCC?

I like it.  While it may not have the raw velocity or muzzle energy of a 6.8 SPC, it does offer shooters a step up in performance over the 223 Remington- while utilizing a common parent case, standard bolt and magazine.  I find this cartridge particularly interesting for the hunting deer within 200 yards.  While I wouldn’t take a quartering shot on a monster buck in heavy cover, I would feel adequately equipped for a hunt in the northeastern woods.

For a high volume shooter, a downside would be the extensive brass preparation and fire forming required.  Looking at the length of the cartridge neck (.145″), I was actually surprised it shot as well as it did (a major criticism of the 300 Winchester Magnum is the short neck length compared to its bullet diameter).

If you are an AR guy looking to get into wildcats this may be the ticket for you.  For more information on the 6.5 PCC contact Illirian Engineering and Design.

Doug H.- thank you for your assistance.

 

For information on alternative AR-15 cartridges take a look at:

Wilson Combat’s 7.62x40WT (Wilson Tactical) Review

300 AAC Blackout Review

Remington R15 30AR Review (Model 60100)