The PSG1 is mechanically based on the
Heckler & Koch G3 battle rifle that employs a
roller-delayed blowback operating system. Its shot-to-shot variation is expected to be better than 1
minute of angle (MOA) with match ammunition. This level of accuracy is only average compared to most modern bolt action sniper rifles, but is still exceptional for a semi-automatic rifle and at one time was claimed to be "one of the most accurate semi-automatic sniper rifles in the world." The rifle has a strengthened receiver with rails welded over the channels where a retractable buttstock would slide and features numerous other upgrades and such to meet the necessities of police sniper units. The two sliding locking rollers that hold the bolt in battery during firing are not cylindrical shaped like in normal G3 rifles, but semi-cylindrical shaped to offer a non-random more precise positioning on corresponding flat surfaces in the barrel extension locking recesses. The PSG1 also features a low-noise bolt closing device (similar to the
forward assist on many
M16 rifles). PSG1s are not supplied with
iron sights but come equipped with the
Hensoldt ZF 6×42 PSG1
scope with an illuminated
reticle. The scope has a built-in
bullet drop compensation range adjustment feature which can be adjusted from 100 to 600 m. It has a heavy
free-floating barrel with
polygonal rifling and an adjustable stock. The stock is of high impact matte black plastic and has a high degree of adjustment. It is adjustable for length, and includes a pivoting butt cap and a vertically-adjustable cheekpiece. The forend is fitted with a T-way rail for sling swivel or tripod. The rifle also features a removable and adjustable trigger unit, for further individual fitting of the rifle. The trigger pull can be modified and the whole assembly is removable from the pistol grip. The pistol grip is of a target-style with an adjustable palm shelf.
PSG1A1 The
PSG1A1 variant was introduced by Heckler & Koch in 2006, and features two major improvements. First, the cocking handle was relocated a couple of degrees counter-clockwise. This was because when locked rearward, it could physically interfere with the long scopes often used on the rifles. The second modification involved the replacement of the outdated Hensoldt scope. Non-police users often found the scope's 600 m range limitation and simple crosshairs inadequate for their needs. In addition, the rechargeable batteries are difficult to recharge and for which to find replacements. A final fault is that Hensoldt does not service the scope in the United States. For these reasons, the PSG1A1 has been outfitted with a
Schmidt & Bender 3–12×50 Police Marksman II scope, mounted on rings. To remedy brass ejection a
brass catcher must be installed. ==MSG90==