Like the .300 AAC Blackout and unlike the 6.8 SPC and other "larger bore" AR-15 cartridges, the .277 Wolverine is based on the widely available 5.56×45mm parent case.
Initial design focused on optimal performance with supersonic bullets in the 85-115 gr (5.5-7.5 g) class, therefore a 1:11 twist rate barrel with 5R rifling was selected.
Initially developed, tested, and marketed as a proprietary cartridge, MDWS publicly released the detailed chamber and headspace specifications for the .277 Wolverine in June 2015.
[citation needed] Ready-to-load brass and/or loaded ammunition is available commercially from several sources including: JB's Firearms, LLC and OutdoorShooterSupply.
In October 2017, Starline produced 50,000 newly manufactured cases head-stamped ".277 WLV" for MDWS; all were sold in under 72 hours of posting.
[citation needed] 277/6.8mm bullets are widely available from all major reloading component manufacturers (e.g., Speer, Sierra, Hornady, Nosler, Barnes, Remington, Winchester, Woodleigh, Lehigh Defense, Hawk, etc.)
in a wide range of bullet weights from 85 to 200 grains (5.5-13 g) and styles useful in the .277 Wolverine - including lead-free practice, competition target, varmint, defensive, and game hunting.
[citation needed] The AR-15 family of rifles has been chambered in a wide range of cartridges, from the diminutive .17 rimfire up to the massive .50 Beowulf.
After researching both of them extensively, and having a lot of conversations with many, many experienced professionals and enthusiasts, I decided to move forward with a new cartridge design that would hopefully combine the attributes of both, and dismiss the deficiencies.
With the success of the 300 BLK, hand-loaders wondered which other bullet options could be adapted to fill the opportunities between the two existing extremes, using an AR-15 pattern rifle.
However, when shortening a bullet to create an option with a lower weight, there is a limit that should not be exceeded when a good ballistic coefficient is desired in order to maintain the best possible stability, accuracy, and retained velocity at the longer ranges.
When a fired bullet slows to the supersonic-to-subsonic transition speed (roughly 1,100 FPS at sea level, slightly lower at higher altitudes), its can lose stability.
Although the .277 WLV and the 300 BLK can both fire a selection of heavy or light bullets, the barrel rifling twist-ratio is fixed, and is chosen to optimize the expected task that will be given to it.
For both of these calibers, longer-range shooting with light bullets at super-sonic velocities can benefit from a longer barrel and a relatively slow twist, such as 1:11 (one rotation in eleven inches).
Sub-sonic velocities using heavy bullets have the option of using a much shorter barrel, and are more accurate when using a relatively fast rifling twist, such as a ratio near 1:8 (one rotation in eight inches).
This means that although they both use the same parent case, the 277 WLV has more powder capacity, which is a benefit when trying to achieve the best possible velocity when using the lighter super-sonic bullets (24.5 gr of water in an unloaded case for the 300 BLK, 27.6 gr for the .277 WLV) When using the AR-15 family of rifles, all three of these alternative calibers use the same bolt carrier group (BCG) and upper receiver as the standard 5.56 x 45 rifle.
The 300 BLK requires the forward-most alignment ribs inside the NATO STANAG magazines to be removed, due to the larger diameter of the bullet.