Franklin Armory has issued a warning to folks who own one of their F17 series of AR15 rifle in 17WSM. If you own one of these rifles, please read the following information on cleaning with foam style cleaners, and using after-market triggers:
F17 SERIES OWNERS SAFETY WARNING!
* DO NOT USE FOAM CLEANERS ON YOUR F17 SERIES FIREARM.
* IF YOU HAVE USED A FOAM CLEANER, DO NOT SHOOT YOUR FIREARM AGAIN UNTIL YOU HAVE REMOVED ALL TRACE RESIDUE OF THE FOAM PRODUCT.
* IF YOUR PISTON IS NOT FREELY TRAVELING THE FULL LENGTH OF IT’S STROKE, DO NOT SHOOT THE FIREARM AGAIN UNTIL IT IS EVALUATED BY A COMPETENT GUNSMITH.
* DO NOT USE ANY F17 SERIES FIREARM WITH AN AFTERMARKET TRIGGER FEATURING A CANTILEVERED HAMMER FACE. IT MAY STRIKE THE FIRING PIN WHEN THE ACTION IS OUT OF BATTERY.
* ALWAYS WEAR EYE AND EAR PROTECTION WHEN SHOOTING.
Since the foam is designed to expand into every nook and crevasse, it flows through the gas port, into the gas block/cylinder.
We have had a couple of instances where FOAM CLEANERS were used by customers to clean their F17 rifles. Since the foam is designed to expand into every nook and crevasse, it flows through the gas port, into the gas block/cylinder. Whence in the cylinder, the sticky foams can generate carbon accumulation. The carbon would normally be blown out by the pressure of the gas port, but because the foams can stick like a gum residue, the carbon can cake up in the cylinder and around the piston. If this should occur, the piston will not be able to travel fully forward. If the piston travel is restricted, then the carrier will possibly bend the piston rod due to the restriction.
MORE IMPORTANTLY, it is also possible that the piston may keep the carrier from traveling fully forward and the bolt lugs from fully locking. If the firearm is also used with an aftermarket trigger that happens to have a cantilevered hammer face, it is possible that the firing pin may be struck WHILE THE ACTION IS NOT FULLY IN BATTERY!
If you have any doubt about the condition of your F17 Series rifle, then do not shoot it until you can have a competent gunsmith evaluate it. While it is best to remove the handguard to evaluate piston travel, a quick test can be performed by first ensuring that the firearm is unloading, then removing the upper from the lower, then removing the charging handle and bolt carrier group from the upper, and finally tilting the muzzle up and down. The piston should freely travel and provide an audible “clank” with every motion. If this test is in any way inconclusive, do not shoot the firearm again until it is evaluated by a competent gunsmith.