The Iver Johnson AMAC-1500/5100 (aka RAP Model 500 or aka RAI 500 or, depending on source, 'AMAC-1500' or 'AMAC-5100') is a 36 lb manually-operated single-shot sniper rifle/anti-material rifle. The 29" barrel with a massive 7" two-stage muzzle brake on its end (barrel plus muzzle brake OAL of 36") has a 1 in 14" twist rifling rate, an adjustable crisp trigger pull between 3 lbs - 8 lbs, an adjustable stock length of pull between 13.75" to 15.5," and a stock comb adjustable to +1.5" for operator tuning. The rifle featured a removable "shell holder" rotating bolt with three lugs. For each shot, the removable bolt was rotated and removed from the receiver, then a cartridge was inserted into a half-circular retaining ridge breech bolt face, and then bolt with cartridge were inserted back into receiver and locked closed prior to firing pin cocking and firing. As such, there is no 'safety' once the bolt is engaged with a live round other than counter-rotating the bolt from the locked position. The rifle does not have any integral open sights as only telescopic sights were intended to be used. The integral receiver dove-tail rail with cross-key is set up for a scope mount with fixed ring spacing and 60 min of angle elevation. The rifle was not designed to be fired offhand, and thus had no forearm; instead, each rifle was issued with integral stout folding bipod attached to the receiver that allowed harmonic tuning adjustment in the bipod tube. For carry, rifle was easily disassembled into several major parts. There are several variants that also have larger calibers for this same design. Design and Background The Iver Johnson AMAC-1500/5100 is a derivative of the RAP Model 500, which was originally designed by a team led by Jerry Haskins of Research Armaments Prototypes (RAP, or RAI [incorporated]) (Jacksonville, Arkansas) as the Model 500 in 1981 at the request of US Armed Forces (SOCOM not created until April 16, 1987). Jerry Haskins formerly worked with Doug Champlin of Champlin Firearms but left to form his own company in 1971 (name confusion lists D. Haskins as the creator which was a misnomer of Champlin's first initial and Haskins last name). Both weapons are similar; the main differences are the barrel shape, the muzzle brake, and the bipod. Subsequently, the design was purchased by Daisy Weapon Systems (Rogers, Arkansas) who sold the AMAC 1500/5100 manufacturing