Whether you\u2019re stacking coyotes and hogs, a law enforcement officer on duty, or defending what\u2019s yours, performance isn\u2019t negotiable.<\/p>\n
The M855 green tip and Mk318 have been the standard for decades, each with its own strengths. But let\u2019s be honest\u2014they\u2019re not perfect. The M855 punches through barriers but lacks reliable stopping power. The Mk318 expands better but isn\u2019t the ultimate solution.<\/p>\n
Enter the HOP Munitions 62-grain Solid Copper REX. Built to outperform both, this round delivers devastating energy transfer, accuracy, and barrier-blind performance\u2014without the downsides of traditional loads.<\/p>\n
M855 Green Tip: The Military Workhorse<\/h2>\n
The M855, widely recognized as the \u201cgreen tip<\/a>,\u201d is a 62-grain full metal jacket round featuring a steel core. Designed for military use, its primary advantage is penetration, making it effective against lightly armored targets. Key specifications include:<\/p>\n While the M855\u2019s steel core enhances penetration, its terminal performance can be inconsistent. Fragmentation is unreliable, and expansion is minimal, limiting its effectiveness for hunting or applications where immediate stopping power is critical.<\/p>\n The Mk318 Mod 0<\/a>, often referred to as the \u201cSilver Bullet,\u201d was developed to overcome the M855\u2019s shortcomings. Extensively used by the USMC, this open-tip match (OTM) round offers:<\/p>\n The Mk318\u2019s open-tip design facilitates controlled expansion and fragmentation, significantly improving lethality without sacrificing accuracy. However, advancements in ammunition technology have driven the need for even more refined options for tactical, hunting, and duty applications.<\/p>\n Taking cues from the proven performance of the Mk318, we\u2019ve pushed the limits even further with our 62-grain Solid Copper REX<\/a> (Rapid EXpanding) round. Designed to outperform both the M855 and Mk318, it boasts:<\/p>\n These specs translate into deep penetration, devastating knockdown power, and exceptional accuracy\u2014making this round ideal for law enforcement, military, coyote and hog hunting, and home defense.<\/p>\n The Solid Copper REX is engineered for controlled expansion and consistent energy transfer. Compared to the M855\u2019s steel core and the Mk318\u2019s open-tip design, the REX delivers significantly more reliable terminal ballistics. It is the ideal choice for duty use where stopping power is necessary.<\/p>\n With a ballistic coefficient of .300, the REX provides a flat trajectory and excellent wind resistance, ensuring accurate shot placement at extended ranges\u2014critical for law enforcement marksmen and military professionals.<\/p>\n Made entirely from solid copper, the REX eliminates lead contamination while maintaining extreme durability. It reliably penetrates barriers without structural failure, making it ideal for duty and tactical scenarios.<\/p>\n Thanks to its high velocity and energy transfer, the REX is ideally suited for hunting small-to-medium game, home defense, and professional use by law enforcement and military personnel.<\/p>\n Tier 1 military units have long favored the\u00a077-grain Open-Tip Match<\/a>\u00a0(OTM) round<\/span> for its accuracy and devastating terminal performance. Its heavier weight provides excellent flight stability, making it a go-to choice for precision shooting. Notable specs include:<\/p>\n The 77-grain OTM\u2019s boattail and open-tip design contribute to its superior long-range performance. However, to maximize stabilization, it requires a 1:7 or 1:8 twist barrel.<\/p>\n For those committed to 77-grain loads, HOP Munitions also offers a 77-grain HPBT<\/a> option, delivering the same precision and performance expected from this bullet weight.<\/p>\n That said, for shooters looking for a well-balanced alternative, the 62-grain Solid Copper REX bridges the gap between the lightweight versatility of the M855 and the specialized precision of the 77-grain OTM.<\/p>\n Although lighter than the 77-grain OTM, the REX achieves comparable accuracy and terminal effect, making it a practical choice across various mission requirements.<\/p>\n\n
Mk318: The \u201cSilver Bullet\u201d<\/h2>\n
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![\"Mk318](\"https:\/\/cdn-ildeanb.nitrocdn.com\/WfSYgsTNsGINqorISNFoOjQQQrKTrUAP\/assets\/images\/optimized\/rev-ba9458e\/www.thetruthaboutguns.com\/wp-content\/uploads\/2025\/03\/Mk318-Mod1.png\")
<\/figure>\n<\/div>\nIntroducing the Next Generation: HOP Munitions 62-Grain Solid Copper REX (Rapid EXpanding)<\/h2>\n
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![\"HOP](\"https:\/\/cdn-ildeanb.nitrocdn.com\/WfSYgsTNsGINqorISNFoOjQQQrKTrUAP\/assets\/images\/optimized\/rev-ba9458e\/www.thetruthaboutguns.com\/wp-content\/uploads\/2025\/03\/HOP-62-grain-REX-1024x768.jpg\")
<\/figure>\nKey Advantages of the Solid Copper REX<\/h2>\n
Superior Stopping Power<\/h3>\n
Exceptional Precision<\/h3>\n
Eco-Friendly and Durable<\/h3>\n
Versatility Across Applications<\/h3>\n
Closing the Gap on the 77-Grain OTM<\/h2>\n
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![\"77](\"https:\/\/cdn-ildeanb.nitrocdn.com\/WfSYgsTNsGINqorISNFoOjQQQrKTrUAP\/assets\/images\/optimized\/rev-ba9458e\/www.thetruthaboutguns.com\/wp-content\/uploads\/2025\/03\/77-grain-OTM-1024x800.png\")
<\/figure>\n<\/div>\nWhy Switch to the 62-Grain 5.56 REX?<\/h2>\n