Normally muzzle brakes are fitted to reduce recoil, jump and flash. The Sako factory TRG muzzle brakes are however detachable if a user does not wish to use one. Generally TRGs are outfitted with a Zeiss or Schmidt & Bender PM II telescopic sight with fixed power of magnification or with variable magnification. Variable telescopic sights can be used if the operator wants more flexibility to shoot at varying ranges, or when a wide field of view is required.
The TRG-42 has a reputation for being very hard on sighting and mounting components in its .338 Lapua Magnum chambering. Due to its relative light weight it generates fierce recoil that can damage a high end telescopic sight.
In 1989 Sako Ltd. (Riihimäki, Finland) introduced the TRG-21 precision rifle as a sniper rifle model chambered for the .308 Winchester cartridge. A more hunting orientated variation of the TRG was later introduced as the TRG-S M995, which uses the same receiver (short action) and bolt (different bolt handle) as the TRG-21 with the exception that the receiver is open at the top rather than possessing a cartridge ejection port as found with the TRG-21. Subsequently, a second sniper rifle with a 20 mm longer scaled up magnum action emerged as the TRG-41 in order to take advantage of the .338 Lapua Magnum cartridge. Similarly, a hunting variant of this model, again using the same bolt (different bolt handle) and with the receiver open at the top was introduced as the TRG-S M995 Mag in magnum calibres up to .338 Lapua Magnum.
Even thought the TRG-21 obtained its origins from the successful Sako TR-6 target rifle, the 4.7 kg (10 lb 6 oz) TRG-21 was designed as a result of a thorough study of sniper requirements. With the introduction of the TRG bolt-action, Sako moved away from the modified two-lug Mauser bolt-actions, favoured during the past, to an action with a symmetrical three-lug bolt of 19 mm Ø, displaying a locking surface of 75 mm². The evolution of this design continues to the present and can be found in Sako's most recent hunting rifle offerings, the Sako 75 and the Sako 85.
To make the TRG system more suitable for military use Sako upgraded and improved the TRG-21/41 design in the late 1990-ties. Besides the rifles themselves TRG accessories like the muzzle brake and bipod that lets the rifle "hang" below the hinge-point offering a more stable shooting position with large and heavy aiming optics on the rifle where also improved. This resulted in the TRG-22/42 rifle system.
Sako never totally forgot the target rifle origins of the TRG system. The necessary accessories to attach sighting components such as match grade peep sights or target aperture sights and a mirage strap are all available. Equipped with these accessories the TRG can be used for non military or law enforcement tasks such as 300 m UIT standard rifle competition, CISM competition or other kinds of full bore target shooting. The rifle is commonly seen in long-range competition where it has done very well.
The TRG system’s purposive design features, reliability in adverse conditions and consistent accuracy performance (a capable marksman can expect ≤ 0.5 MOA consistent accuracy with appropriate ammunition) have made it a popular, though expensive, sniper platform.
The TRG’s main commercial competitor/equivalent on the high end factory sniper rifle market is the Accuracy International Arctic Warfare product line, that is capability wise generally on par with the TRG system but even more expensive.
The TRG system is almost unique in being a purpose-designed sniper rifle, rather than an accurised version of an existing, general-purpose rifle.
The heart of the TRG system is a cold-hammer forged receiver and barrel. Both provide maximum strength for minimum weight as well as excellent resistance to wear. The "resistance free" bolt has three massive lugs and requires only a 60-degree bolt rotation; both features should be appreciated by the shooter during multiple firings that require rapid projectile placement on the target. The bolt handle is the appropriate length and sports a large synthetic bulbous knob that provides a firm, positive grip. On top of the receiver a 17 mm integral dovetail rail with shape connection drillings for a recoil lug provides for fixing mounting components to accommodate different types of optical or electro-optical sights. Folding iron sights can be obtained for secondary or emergency use.
The free-floating, heavy, chrome moly barrels (chrome moly barrels resist throat erosion better offering a longer accuracy life than stainless steel barrels) for the available cartridge chamberings all have a different length, groove cutting and riflingtwist rate optimized for their respective chambering and intended ammunition. On special order TRG rifles can also be supplied with stainless steel barrels. Two types of flash eliminator/muzzle brakes are available as an accessory with one being threaded to accommodate a sound-suppressor.
For the .308 Winchester chambering the 280 mm (1 in 11 inch) right-hand twist with four grooves was selected over the 305 mm (1 in 12 inch), traditionally found for the .308 Winchester, as a compromise when switching between supersonic and subsonic cartridges. The .300 Winchester Magnum chambering also has a non-traditional 280 mm (1 in 11 inch) right-hand twist rate. For the .338 Lapua Magnum chambering an also non-traditional 305 mm (1 in 12 inch) right-hand twist rate was selected to optimize the rifle for firing 16.2 gram (250 grain) .338-calibre very-low-drag bullets. Longer, heavier very-low-drag bullets like the Sierra HPBT MatchKing .338-calibre 19.44 gram (300 grain) require a 254 mm (1 in 10 inch) twist rate to stabilize them.
The receiver's large bedding surface is mated to an aluminium alloy-bedding block by three screws for maximum stability. This combination ensures an unusually high degree stability.
A great deal of creative thought was expended for the TRG stock design. In addition to sniping requirements, the TRG is designed to conform to both UIT and CISM regulations. The base of the ergonomic injection-moulded polyurethane forestock is made of aluminium and encompasses the bedding block with the bedding block serving as a point of attachment for a bipod. The polyurethane buttstock with its pistol grip and integrated aluminium skeleton to add strength, is designed for right- and left-handed shooters. The rear of the buttstock possesses a series of spacer and angle plates to regulate the length of pull and curvature adjustments that can be tailored for the individual shooter. The buttplate is adjustable for both height and pitch. Finally, the cheek-piece is adjustable for both height and pitch as well.
An almost over-engineered folding skeleton type buttstock designed for right- and left-handed shooters is also available. The stock is hinged behind the pistol grip and folds to the left side and locks into position. In folded mode TRG rifles become 250 mm shorter. The steel parts of the folding stock are manganese phosphatised and the polyurethane parts are coloured olive drab. The rear of the buttstock is adjustable for length of pull and height. The cheek-piece and rear support are also adjustable for height. These adjustment options allow shooters of various sizes and shapes to tailor the TRG folding stock to their personal preferences and are quite rare for folding stocks. The pistol grip body has a steel loop for a hook type military sling swivel.
The safety lever is located in front of the trigger inside of the trigger guard and can be operated without producing mechanical noise. The two-position safety locks the trigger mechanism, locks the bolt in closed position and blocks the firing pin. The safety is on when it is in its rearmost position. It is off when it is pushed to its most forward position. When the weapon is cocked the firing pin protrudes from the rear of the bolt-action, making it possible to feel if the weapon is ready to fire or not in poor visibility.
The two-stage trigger mechanism displays an adjustable trigger pull weight of 1 to 2.5 kg (2 to 5 lb) and can be adjusted for length, horizontal and vertical pitch. The advantage of these features is to prevent trigger movement in an inappropriate direction that would cause the rifle to move off target. Trigger travel is short with no noticeable over-travel. As a safety factor, a safety notch is incorporated into the trigger in order to prevent discharge resulting from a strong impact on the rifle. The smooth operating safety lever is located inside the trigger-guard. It locks the trigger mechanism in addition to locking the bolt in a closed position and to blocking the firing pin. A major advantage of the TRG is that the trigger mechanism can be removed without additional disassembling of the rifle.
The detachable box magazine is based upon centre feeding for maximum reliability as well as precise positioning of the cartridge into the chamber.
A sling attaches to the left or right side of the buttstock by pushing the quick detachable swivel into a socket located at the read of the stock. The forward portion of the sling attaches to rails located on the side or underside of the forestock.
Sako accessories for the TRG system include auxiliary iron sights for emergency use, a muzzle brake/flash-hider, match sight mounting set, telescopic sight mounting sets, MIL-STD-1913 rail (Picatinny rail), accessory tri-rail for TRG forestock (top), accessory rail for TRG forestock (bottom), night sight adapter, silencer (sound suppressor), various slings and swivels, cleaning kits, soft case, and a heavy-duty transit case.
Template:FIN - The Finnish Army purchased 490 TRG-42 rifles. It is known as the 8.6 TKIV 2000 The Finnish Defence Forces (FDF) 8.6 TKIV 2000 rifles have custom made Zeiss 3-12x56 Diavari VM/V T* 30 mm telescopic sights with eye safe laser filters mounted. These sights are equipped with first focal plane "FinDot" reticles (a regular mil-dot reticle with the addition of 400 m – 1200 m holdover (stadiametric) rangefinding brackets for 1 meter high or 0.5 meter wide targets). Reticle illumination is provided by a tritium ampoule embedded in the elevation turret. The elevation turrets have 100 m – 1400 m Bullet Drop Compensation (BDC) knobs calibrated for the Lapua Lock Base B408 cartridges the FDF issues its 8.6 TKIV 2000 marksmen. FDF snipers are trained to compensate BDC induced errors that inevitably occur when the environmental and meteorological circumstances deviate from the circumstances the BDC was calibrated for. The reticle elevation has 0.25 mil (0.25 mrad) adjustment intervals (total elevation range = 18.6 mils), while the windage has 0.1 mil adjustment intervals. The FDF thinks 0.25 mil elevation intervals are easier and quicker to use with Arctic mittens and that the difference between 0.1 and 0.25 mil adjustment intervals is negligible for anti-personnel sniping (0.1 mil at 1400 m = 14 cm (0.3437747 MOA), 0.25 mil at 1400 m = 35 cm (0.8594367 MOA)). All vital screw slots are designed to be operated with .338 Lapua Magnum cartridges instead of screwdrivers.
↑The Finnish Army found out during a test/trails program and 7 years of actual service that the barrels of their Sako TRG-42's lasted 7000 to 8000 rounds with Lapua Lock Base B408 factory ammunition before showing impermissible accuracy decay. The Finnish Army consistent accuracy requirement for these rifles is ≤ 1 MOA at 1000 m. If this requirement is not met the TRG-42 gets a new .338 Lapua Magnum barrel. This is normal practice for active high performance precision rifle operators who regard barrels as expendable items. The continuous use of very powerful handloads (which results in higher muzzle velocities) resulted in much quicker throat erosion reducing the TRG-42 barrels accuracy life to 1500 to 2000 rounds.