– 16.25 in Stainless Steel
– Button Rifled – 1 Turn in 16″ Right Hand Twist – all Models and all Calibers
– OD is 0.695″
Weight (basic unit only):

– Approximately 5.3 lbs

Overall Length:


Fixed Stock: 30 1/8 in
Length of pull: 14 1/8 in
Telestock: Min. 25 7/16 in; Max. 33 15/16 in
Length(s) of pull: 9 5/8, 12 1/4, 14 1/4, 16 1/4, 18 1/4 in
M4 Style Stock: Min. 31 3/16 in; Max. 35 1/16 in
Length of pull: 15 3/8 in – 19 1/4 in


Fixed Stock: 29 1/4 in
Length of pull: 13 3/8 in
Telestock: Min. 24 3/4 in; Max. 33 1/8 in
Length(s) of pull: 8 3/4, 11 1/2, 13 1/2, 15 1/2, 17 1/2 in
M4 Style Stock: Min. 30 1/2 in; Max. 34 3/8 in
Length of pull: 14 5/8 in – 18 1/2 in


Fixed Stock: 29 5/8 in
Length of pull: 14 1/8 in
Telestock: 25 1/8 in; Max. 33 5/8 in
Length(s) of pull: 9 5/8, 12 1/4, 14 1/4, 16 1/4, 18 1/4 in
M4 Style Stock: Min. 30 7/8 in; Max. 34 3/4 in
Length of pull: 15 3/8 in – 19 1/4 in

Straight Blowback Action

About interchangeable stocks for the CCU

Older CCU’s with the welded-on fixed stock may be upgraded to accept the interchangeable stock system. You need to order a Retrofit Housing Kit. The kit comes with a new buffer assembly and a new housing configured to accept the interchangeable stock system. On the ‘MANUALS/PRICE LIST’ page you can see the ‘INSTALL STOCKS.pdf’ for more details on how the new stock system works. Also note that the new design housing has a square front. Mech Tech will supply a filler plug which slips over the barrel to bring the retrofit cosmetically up to date. if your barrel has a muzzle dec fitted, the filler plug will not slide over the barrel. Contact Mech Tech and make arrangements to send in just the barrel for dec removal and reinstallation – this will be free of charge but you must pay the return shipping.

Mech Tech CCU in competitive shooting

The Mech Tech CCU is being used in the world of competitive shooting sports! We understand that it meets power factors suitable for the 3-gun events and we have a number of customers using it in them. It makes sense of course to use a familiar grip and trigger pull for long gun shooting. It also simplifies the competition by using 2 ammos (pistol and shotgun) and one set of magazines for pistol/rifle. The USPSA has a pistol caliber carbine division and the CCU is being used there as well. The power gains available from the 16” barrel can be significant.

Selecting ammunition for your CCU

There are certain factors to consider when selecting ammunition for use in the CCU’s. The CCU is a ‘blow back’ type action. The main design element in a blow back is the weight (mass) of the bolt. This must be chosen to anticipate the ‘hottest’ loads encountered. The physics of a blow back action is such that the bolt mass and the bullet weight (mass) work together to limit the amount of the case which is allowed to move out of the chamber while the bullet is still in the bore. When the round is fired two things happen immediately:

1) the bullet begins to move out of the case mouth and up the bore
2) the case begins to move to the rear pressing against the breech face.

To elaborate, the case acts like a piston pushing out of the chamber to the rear and the only thing limiting the amount of movement of the case is the mass of the bolt – contrary to popular belief the recoil spring plays a negligible role in the initial case movement. The real design issue is to limit to a safe value the distance over which the case moves to the rear out of the chamber over the time that the bullet is still in the bore. As long as the bullet is in the bore the gas pressures are high and the case must have sufficient support to prevent case head blow-out or other pressure signs. The bolt weight in the CCU is enough for a good safety margin and as such the ammunition needs to be powerful enough for reliable ejection. Standard 9mm ammunition will work in the CCU. 9mm ammunition labled as ‘target’ loads generally are not ‘hot’ enough to reliably cycle the action.

Use only ammunition of the caliber and style for which the CCU is designed. Only use high quality ammunition loaded by licensed commercial ammunition manufacturers (factory ammunition) which meets applicable SAAMI, CIP or NATO standards. The use of reloads or ammunition from unknown suppliers has the potential to be unsafe and also will void the warranty of the CCU. Mech Tech does NOT recommend using +P+ ammo in our CCU’s.