Internal differences include a new buffer system and a change to polygonal rifling.

Supporters of polygonal rifling also claim higher velocities and greater accuracy.

Polygonal rifling may leave striations that are difficult to match to a particular barrel.

A number of advantages are claimed by the supporters of polygonal rifling.

It has a heavy free-floating barrel with polygonal rifling and an adjustable stock.

Another system, polygonal rifling, gives the bore a polygonal cross section.

The hammer-forged barrel has a female type polygonal rifling with a right-hand twist.

From the G3A3 the barrel had polygonal rifling.

Another feature of this pistol is the use of polygonal rifling in the barrel bore.

The rifling used in the Rogak version was a hybrid of polygonal rifling.

Alternatively MG3 barrels can also have polygonal rifling.

HK also developed modern polygonal rifling, noted for its high accuracy, increased muzzle velocity and barrel life.

Although uncommon, polygonal rifling is still used in some weapons today with one example being the Glock line of pistols (which fire standard bullets).

The PM barrel configuration boasts polygonal rifling, which in theory will wear longer and gather less fouling.

More recently, polygonal rifling, a throwback to the earliest types of rifling, has become popular, especially in handguns.

The Desert Eagle's barrel features polygonal rifling.

The barrel has the same bore profile as the PSG1, including polygonal rifling, and lacks a muzzle device.

Initially Jericho pistols used barrels with polygonal rifling, which sometimes produces slightly higher velocity due to better bullet to barrel fit.

Traditional land and groove rifling is used in most competition firearms, however, so the advantages of polygonal rifling are unproven.

Metford's polygonal rifling was adopted to reduce fouling from powder residue building up in the barrel, and also made it easier to clean as well.

During World War 2 polygonal rifling emerged again in the German MG 42 machine gun.

This type has a smaller bore area than the male type of polygonal rifling designed and used by Lothar Walther.

Some firearms manufacturers, such as those using polygonal rifling like Glock and H&K, advise against the use of cast bullets.

The MG42 successor the Rheinmetall MG 3 machine gun can also have polygonal rifling.

Polygonal rifling is not very common, used by only a few European manufacturers as well as the American gun manufacturer Kahr Arms.