It has been brought to our attention that the bolt weights have some compatibility issues with Ceiner/Atchisson MKII bolts (and potentially other lesser known variants) that have a flat firing pin (listed as “firing pin, flat (MKII)” here: http://www.22lrconversions.com/ordpg-prts-ar.htm).
DO NOT use the bolt weight with a MKII or similar bolt with a flat firing pin, as a dangerous situation may occur.
If your bolt has a round firing pin, (such as CMMG and other recent variants) the weight can be used. See the photos below.
