The video opens by laying out a head-to-head comparison of three key 5.56 NATO loads: M193, M855, and MK262. Each round is matched to a different AR-15 style rifle to illustrate intended use. A retro 20-inch M16-style rifle represents the original platform for M193, a 55-grain ball round developed in the 1960s for 1:12 twist barrels and running around 3290–3250 feet per second. A 14.5-inch carbine with a Trijicon optic is used to showcase M855, the 62-grain “green tip” with a steel penetrator optimized for 14.5–16 inch barrels and intermediate barrier penetration, along with the updated M855A1 variant at roughly 2920 fps. An 18-inch Mk12-type rifle is paired with MK262, a 77-grain open tip match load moving around 2750 fps, designed to trade raw speed for heavier weight and improved long-range accuracy. The concept of grain as a unit of projectile weight is briefly explained to set up later velocity and trajectory comparisons.
The discussion turns to how projectile grain weight only measures bullet mass, not powder charge, and how heavier bullets generally produce lower muzzle velocities. Ammunition selection is framed around mission and purpose, with emphasis on accountability for every shot and the risk of overpenetration when using full metal jacket rounds, especially in home-defense scenarios. Hollow points or frangible loads are recommended for close-range defensive use, while the three 5.56 FMJ-based options are positioned for training and duty roles. M193, at about 55 grains and roughly 3250 fps, is described as a cost-effective, high-speed training and distance round. M855 and M855A1, 62-grain green tip penetrator loads, are highlighted for better performance through intermediate barriers and for dumping energy after penetration. MK262, a 77-grain open tip match round, offers a flatter, more predictable trajectory and higher performance at distance despite lower velocity around 2750 fps. New NAS3 casings from Black Arc Munitions are mentioned for pushing 77-grain OTM rounds toward M193-like speeds, leading into a planned range test using the Mk12 as a precision baseline.
The Mk12 rifle is established as the precision baseline for the live-fire comparison. It is zeroed using a T.REX Arms 25-yard zero target to confirm a 100-yard point of impact, ensuring that subsequent groups from different loads can be fairly compared. Initial velocity readings during this process show numbers in the 3300 fps range, giving a reference for how fast the platform is running under the day’s conditions. With the zero confirmed, the shooter prepares to fire 10-round strings of each ammunition type: M193 55-grain ball, M855 62-grain green tip, and MK262 77-grain open tip match. The test is conducted at 100 yards, with a focus on both group size in minutes of angle and chronograph data for average velocity. Environmental factors such as warm, humid weather and the effect of barrel and suppressor heat are acknowledged as variables that may influence group dispersion and flyers as the strings progress.
The first full test string uses M193 55-grain ball ammunition. Ten rounds are fired from the Mk12 at 100 yards, with velocities recorded in the low 3300 fps range and an average around 3324 fps, confirming that M193 is the fastest of the three loads tested. On target, the M193 produces a group roughly in the 1.5–2.5 MOA range, with one notable flyer that may be attributable to a cold bore shot or early string conditions. Despite not being a match-grade load, the M193’s performance is described as acceptable and consistent enough for emergency or fighting use, especially given its affordability and availability for bulk training. The results reinforce M193’s role as a high-speed, general-purpose round that can still deliver combat-effective accuracy out to typical engagement distances when fired from a quality rifle like the Mk12.
Next, the test moves to M855 62-grain green tip ammunition, featuring a steel penetrator core. A 10-round string is fired from the same Mk12 platform at 100 yards. Chronograph data shows an average velocity around 3070–3073 fps, clearly slower than M193 but still within typical 5.56 NATO performance. On paper, the M855 groups exhibit more vertical stringing and a looser overall pattern, estimated in the 2.5–3 MOA range. Some rounds cluster reasonably well, but there are noticeable flyers and inconsistent impacts that spread the group vertically. The shooter notes that barrel heat, suppressor temperature, and the warm, humid conditions may contribute to this erratic behavior, yet the pattern still appears more variable than with M193. The coverage on target is described as strange and less predictable, suggesting that while M855 offers barrier penetration advantages, it may not deliver the same consistency or precision as the other loads in this particular rifle.
The final live-fire string uses MK262, a 77-grain open tip match round from Black Hills. Ten rounds are fired from the Mk12 at 100 yards, with the chronograph showing significantly lower velocities around 2780 fps and an average near 2788 fps, reflecting the heavier projectile. Despite the reduced speed, the on-target performance is clearly superior. The MK262 groups are noticeably tighter, estimated at about 1.25–1.5 MOA or better, with several shots stacking closely together. The consistency is attributed in part to Black Hills’ strict lot-to-lot standards and the match-grade nature of the OTM projectile. The heavier 77-grain bullet is also noted as being less affected by wind and external environmental factors, enhancing its suitability for long-range and precision applications. These results reinforce MK262’s role as the top-tier, accuracy-focused 5.56 load in the test, trading velocity for precision and downrange stability while still remaining combat effective.
After reviewing the targets, the discussion compares the three loads in terms of combat effectiveness rather than pure benchrest precision. Anything that can stay within a roughly 3-inch circle at 100 yards is considered combat effective for typical engagements. M193, with its 1.5–2.5 MOA performance and high velocity around 3324 fps, is seen as a fast, viable fighting round, especially for emergencies and general-purpose use. M855’s 2.5–3 MOA groups and vertical stringing make it less predictable, though its penetrator core still offers advantages against intermediate barriers. MK262 stands out with 1.25–1.5 MOA or better, delivering tight, repeatable groups and benefiting from its heavier 77-grain bullet’s resistance to wind and atmospheric disturbances. The impact of heat, suppressor temperature, and humid conditions on group size and flyers is emphasized, underscoring that real-world performance is influenced by more than just factory specifications and advertised velocities.
The video concludes by naming MK262 as the clear top-tier 5.56 round among those tested, thanks to its consistent 1.25–1.5 MOA accuracy, tight stacking groups, and stable external ballistics. When forced to choose between M193 and M855, the presenter favors the 55-grain M193 due to its more predictable grouping and the fact that its single notable flyer can be explained as a cold bore shot, whereas M855 showed odd vertical dispersion and inconsistent impacts. The conversation shifts to what shooters actually buy, stockpile, and train with, including the idea of keeping bulk quantities of cheaper loads while occasionally purchasing smaller amounts of MK262 for serious use. Practical advice is given to zero rifles with the load that will be fired most often, such as M855 if that is the primary training round, while recognizing that shooter skill ultimately determines real-world accuracy. The importance of matching ammunition choice to mission, budget, and realistic engagement distances is emphasized.
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