My 4 ar15's has 3 oz -+ buffers (5.56 ,300blk,22lr,223 rifle)16 " barrels for carbine ,20" for the rifle and they all run fine with factory or reloads . My Ar 10 has a 4 oz - + buffer 16 " barrel carbine and it has a very firm recoil off a lead sled(25lb weight) with horadry steel match 147gr ,a lesser firm recoil with 150gr /39.8gr imr 4895 off a bag, but double feeds and fte's with the reloads( about 200 rd down the tube on the 308 ). the question is should I go to a heavyer buffer H3,H4( 5 oz+, 6.4oz) on the 308 or wait till I have more rounds down the tube first and would a H2 ,H3 on the 556 and 300 blk help improve recoil with them ??