Buffers are timing devices like a distributor, but will also cause short stroking if too heavy or not enough gas.
I'm sure everyone has seen this chart above. I pick the heaviest in the chart for that particular barrel thats suppressed. Like 16in mid gas I used an h2 for use with a can.
Pic above is cam pin strikes in a 20in 6x45 rifle gas with h3 bullfer. Suppressed with warm loads.
^^^ 16in mid gas 6.8 with h2, suppressed warm loads. Probably should put an h3 in it.
^^ 16in 223 carbine gas with standard 3 ounce buffer suppressed with mild loads h3 buffler would have prevented this. Bolt unlocks waaaay too early. Makes gun extremely nasty too.
All these guns had adjustable gas blocks for every single shot and were adjusted to the last click that the bolt was held open on last shot with empty mag. When I look at other guns it's the first thing I look for to see if timing is correct.