Frog48
Member
I have a Bushmaster M4 style carbine, with flat top and removable carry handle. I've done some searches online, and apparently I cannot use backup iron sights unless I also replace the front sight post with a taller one, because Bushmaster does not use "F marked" front sight bases on their flattop models.
What other companies do not use F marked bases on their flattop models?
What other companies do not use F marked bases on their flattop models?