Introducing the 6.8x45mm UCC Urban Combat Cartridge

Kramer Defense Solves AR-15 Ballistic Inadequacies

6.8x45mm Urban Combat Cartridge UCC Ammo
6.8x45mm Urban Combat Cartridge UCC Ammo
Kramer Defense
Kramer Defense

 Las Vegas, Nev. – -( After four years of research and development, Kramer Defense announced the commercial release of the 6.8x45mm Urban Combat Cartridge (UCC) as a cost-effective, ballistically superior upgrade for the AR-15, M16, and M4 platforms.

The 6.8x45mm UCC provides military, law enforcement, and civilian users the ballistic performance similar to the 6.8mm Remington Special Purpose Cartridge in a package that is significantly more cost-effective and easily retrofitted to existing AR-15 patterned carbines.

Based on the 5.56 NATO cartridge case, the 6.8x45mm UCC offers a significant ballistic advantage over its parent cartridge and even outperforms the 7.62x39mm and the popular .300 AAC Blackout cartridges, when fired from similar barrel lengths.

The accompanying ballistics chart comparing these cartridges shows the advantage that the 6.8x45mm UCC provides the user.

6.8x45mm Urban Combat Cartridge UCC Ballistics Chart
6.8x45mm Urban Combat Cartridge UCC Ballistics Chart

The result of the company’s development work is a cartridge that offers AR-15 users the ultimate in flexibility. The 6.8x45mm UCC has proven to be ballistcally superior in short-barreled AR-15 carbines, cycles flawlessly in selective-fire weapons, handles projectiles suitable for hunting applications, and has performed extremely well in initial sound suppression tests.

“While we were focused on a solution for combat, the end result is probably the most efficient cartridge you can put in an AR-15,” said Larry Kramer, president of Kramer Defense.

“The 6.8x45mm UCC offers the best trade-off balance of increased terminal performance, cartridge size, projectile weight, velocity, weapon compatibility, magazine capacity and controllable recoil. It really is the ultimate intermediate caliber.”

Kramer Defense has loaded ammunition and complete AR-15 upper receivers for the 6.8x45mm UCC in stock and ready to ship.

6.8x45mm Urban Combat Cartridge UCC
6.8x45mm Urban Combat Cartridge UCC


Kramer Defense currently offers two commercial loadings for the 6.8x45mm UCC:


AR-15 Upper Receivers

  • Complete upper receivers available through Kramer Defense feature:
  • High pressure tested and magnetic particle inspected bolt
  • Premium Lothar Walther barrels made of LW19 chrome moly steel that are polygonally rifled, chromed lined and have a twist rate of 1:11.3


About Kramer Defense

Kramer Defense is a veteran owned and operated, small business located in Las Vegas, Nevada founded with the goal of designing new cartridges and operating system components for the AR-15 / M16 / M4 weapon systems. All products made by and for Kramer Defense are manufactured in the U.S.A. For more information visit

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Young Thomas

Isn’t this just a direct ripoff of the .277 Wolverine?




No, it’s not a ripoff of the 277 Wolverine. The 6.8×45 Kramer was introduced to the public in June of 2008.
The Wolverine was developed in 2014, and the specs and details released in June 2015.
Kinda hard to rip-off something that doesn’t show up til 7 years later.
Both great little cartridges, developed by two great companies. Shame they draw out these kinda silly comments.


Oops! I meant to also post this link for the 277 Wolverine


Could use the same projectile in a 6.8X48mm cartridge!


Tactical advantage is a reason for more knockdown punch. Exceeding thresholds that have stood for a long time makes the AR platform a much greater threat. The compatibility issue is more than icing on the cake.


Well as a combat cartridge it will easily exceed the 5.56…You know…that cartridge that never should have been in the first place…100-120 grain bullets will take all the medium game in the US…Penetrate harder targets…You know the things that are expected from a competent cartridge…Only swap out the barrel and comp and your good…This is what the 5.56 should have been in the first place…I was actually wanting a 7mmx45 but this may just be what I’m looking for…Considering the limitations the AR mag and rifle present this is a great idea…

Adam Anderson

If you are going to compare to the 5.56 please post the data for the double tap 80gr HPBT and Hornady 5.56 superformance 75gr AMAX. This is a more realistic representation of decent 5.56 ammo vs now retired and obsolete practice rounds. Also include the 270 wolverine that is gaining a lot of traction. And while you are at it post about the 6×45 and pick a solid load from Corbon or 85gr from black hills. These and many others have all superior power to the blackout and russian and they are easy to load rounds and they use standard… Read more »

Justo Cruz

Military personnel and Law Enforcement agencies have been using the 5.56 round successfully for many years. I see no reason to switch to any of these odd ball rounds that will probably not even be in production in the next 10 or 20 years from now. 5.56 and 7.62×39 has been around since before I was born. If it was good enough for them before my time it’s good enough for me.


This is very interesting and I would like to see more ballistic information about the cartridge and comparable weights in all ranges from lite to heavy bullets. Plus reloading information on this cartridge and equipment.


Yawn…… What can this do that my 6.8 SPC II can’t.

Steve Stave

Well you you won’t need a different bolt and magazine for starter’s


It is my understanding the magazines do have to be modified for the neck.


i am definitely interested I would like to see the cartridge so you have them for sale now and does anyone make dies!
What is the parent cartridge the .223 rem/ 5.56x45mm and the necked up to the 6.8? I have 300 balls and I am not impressed I don’t like the 6.8 doc so is this going to be the next disappointment? Just let me know about dies and parent cartridge and will it be anything heavier than the 120 gr!
Like I say definitely interested and I am a 35 year gunsmith so I can sell it sure!!!!