Noted in this article: www.defensereview.com/...News&file=print&sid=741...

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..."Constant-Recoil" for gas-operated firearms/weapons was invented and patented by the famous, prolific, and Chinn Award-winning small arms designer/developer Jim Sullivan (L. James Sullivan) for his Ultimax 100 LMG (5.56x45mm)....Sullivan invented Constant-Recoil for gas-operated weapons in order to make the ultra-lightweight Ultimax fully/easily-controllable when fired on full-auto (off-hand shooting). He owns the patent on it (which has since expired)...

Sullivan's latest small arms project, the "Backbone" Weapons System (a.k.a. "Backbone" Family of Lightweight Small Arms and Ammo") utilizes something called "Constant-Reaction" to accomplish the same recoil mitigation/attenuation as "Constant-Recoil" in a lighter, more compact envelope. The "Backbone" is a true family of machine guns, including (but not limited to) an 11-pound, 100-shot 7.62x51mm BFR (Belt-Fed Rifle) GPMG (General Purpose Machine Gun) that's fast-reloadable on the move (as fast to reload as an assault rifle) and a 6.5-8-pound (depending on config.) 60-100 shot 5.56x45mm Rifle/MG assault rifle/LMG/SAW (Light Machine Gun/Squad Automatic Weapon). Once fully-developed, the "Backbone" family of machine guns will signficantly outperform all currently fielded machine guns in most (if not all) combat-relevant aspects--including (but not limited to) the FN M249 SAW, FN MK46 MOD 0 SAW and FN M240 GPMG.
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