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LWRC Piston System Technology
Reports from military organizations who have compiled
data, both empirically and through testing, deficits were found related to
the issued legacy direct impingement carbine. In response LWRC set out to
engineer, develop and produce a line of self regulating short stroke
piston operated carbines for military, law enforcement duty and for
civilian use. Those deficits of the legacy carbine identified were:
- Decreased reliability
- Decreased weapon service life
- Increase weapon down time due to repairs and
maintenance
- Pronounced muzzle rise and recoil
- User maintenance intensive
- Environmentally sensitive
- Rapid heating in sustained fire leading to small
parts and catastrophic failure
- Bolt lug failure
- Poor terminal ballistics related to the 5.56 NATO
cartridge
LWRC engineered a solution that retains 80% parts
commonality with the issued legacy carbine. The principal improvement
comes with the incorporation of a self regulating short stroke gas piston
system. The low mass "cup and nozzle" system uses 100% of tapped gas
pressure to overcome the mass and resistance of the carbine’s moving
parts. Once the mass and resistance is overcome, the system vents all
excess gas in a "staged vent and dump" of residual gas.
The system is so efficient; it does this in only 6/10ths
of an inch of movement. Extraction is far more positive and consistent
shot to shot. Regardless of the loading, the piston only uses as much
force as is required to cycle the action. No more, no less. The piston
stroke is consistent even with a suppressor in use.
Most importantly, none of the trapped gasses are
channeled into the bolt carrier group or the receiver of the weapon. That
alone eliminates the intensive cleaning regime of the legacy rifle. It
also means the bolt carrier group and associated springs are not subject
to the searing heat of the tapped gasses which can lead to parts failure.
All carbon is vented harmlessly under the hand guards or rail system. LWRC
carbines are far more reliable regardless of user maintenance than the
legacy direct impingement carbines.
The weapon chamber temperature is lowered as the upper
receiver and rail system are no longer searing hot from tapped gasses and
can now effectively operate as a heat sink conducting heat away from the
receiver extension and chamber.
The short stroke piston system employing a "cup over
nozzle" short stroke arrangement limit the reciprocating weight of the
piston system and thus prevents disturbing the barrel harmonics and
accuracy. With reciprocation of the piston cup, carbon is scraped away
from the internal walls of the cup by the fixed ribbed nozzle and blown
harmlessly out of the vent holes with the next cartridge fired. This makes
the piston system almost maintenance free.
The differences in handling characteristics of LWRC’s
weapons over the direct impingement legacy weapons are astounding. Recoil
is light, muzzle rise is greatly reduced. It is most amazing that this can
be accomplished with an LWRC carbine that is ergonomically identical with
almost no weight penalty over the legacy direct impingement carbine.
Terminal Ballistics
While LWRC manufactures weapon in chambered in 5.56mm
NATO, LWRC embraced the Rem 6.8mm SPC to address the poor terminal
ballistics of the NATO cartridge that are exacerbated by carbine length
barrels. 6.8 SPC was developed by military professionals for military
professionals. The weapons platform is identical in size and weight yet
firing 6.8mm SPC, twice the mass is delivered to the target when compared
to 5.56mm NATO. The short pressure curve of 6.8 SPC makes it ideal for use
in short barreled carbines and the optimal operating system is a self
regulating short stroke piston.
Example:
55 Grain M193 (5.56mm) from a 10.5" barrel = ~2350 Feet per second
110 Grain Rem 6.8mm SPC from a 10.5 barrel = ~2290 Feet per second
Clean, cool, reliable, mission essential.
How it Works:
LWRC Short Stroke Piston
Traditional Direct Impingement
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