S size. Positive you will need some force, but this is due to the fact that the short change buckle is held in place by friction. This is likely to be the weak point to anyone but I have found this to become of no problems for me, the sling https://4-30-round-m2-30-cal-maga76414.post-blogs.com/55547008/what-does-black-rain-ordnance-mean