OPS INC™ 7×7 Collar

The 7×7 Collars are a new take on an old Allen Engineering product. Formerly known as the M4 Collar, we renamed them to avoid confusion with the M4 suppressors which they are not compatible. The name “7×7″ comes from the step the collar sits on.

To determine the correct collar sizing you should first verify that you have the correct 7×7 step on your barrel. With a set of calipers, measure the distance between the shoulder and the step. You should be getting around .700″. Now measure the diameter of your barrel between the shoulder and the step. You should be getting around .700”. If both of those measurements line up then you have the 7×7 step.

If you have the correct 7×7 step we can move on to determine the correct collar size. With your calipers, measure the diameter of your barrel after the 7×7 step on the side closest to the gasblock. Whatever size you measure order the matching collar. If you are between the .005″ sizing, round up to the larger size.

A-Mount= AEM5, AEM5k, AEM5-30, AEM5-30k. B-Mount= AEM2, AEM3, AEM4

For more information on fitting it to your barrel click on the MORE INFORMATION tab above.