Yup, they're pins
Cylindrical in shape, definitely pins. 10/10 would pin muzzle device with these again because the NFA and ATF are retarded.
3/32 x 3/16 Dowel Pin for permanently attaching a muzzle device.
Stainless Steel
Cylindrical in shape, definitely pins. 10/10 would pin muzzle device with these again because the NFA and ATF are retarded.