What is the Precision Armament Class 3+™ Advantage?

Class 3+ Thread Class Explained

Class 3+ is a proprietary Unified National (UN) thread class, designed by Precision Armament to provide superior performance in muzzle device attachment technology.

Class 2 is the official Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) spec thread class for all barrel and muzzle device threads. Class 2 provides a minimum fit allowance on the male thread, which ensures the threads will mate with clearance and have a low probability of seizing or galling, even with a little debris in the works. However, the tolerance zones for Class 2 are sizeable, which can result in poor concentricity and alignment accuracy. At best, this will lead to decreased accuracy, and at worst it could result in a baffle strike.

Class 3 threads, on the other hand, feature a much tighter tolerance zone which guarantees more accurate muzzle device and suppressor alignment. However, Class 3 is not a suitable thread spec for barrels and muzzle devices because it does not permit any allowance for fit. Class 3 threads can technically be machined to an interference fit and still be in tolerance. Even when not at an interference fit the slightest particle ingress can result in a thread seizing or galling situation. There is nothing worse than installing that high end suppressor or muzzle brake on your expensive barrel and damaging them both during installation or removal.

Class 3+™ combines the best of both worlds, and then takes it a step further! Class 3+ adopts an even tighter tolerance zone than UN Class 3 threads, which guarantees the most accurate alignment achievable. Additionally, Class 3+ adopts the fit allowance of Class 2 on the male thread and adds additional fit allowance to the female thread resulting in the largest fit allowance of any UN thread class. This provides the absolute lowest chance of thread interference, seizing, or galling. Class 3+ is completely compatible with all existing barrel and muzzle threads and guarantees the highest level of accuracy and the lowest possibility of interference regardless of the thread class it is attached to. This is the Precision Armament Class 3+ advantage.

Precision Armament Class 3+ Products