80 grams is 2.8 oz...looks like you have a standard carbine buffer.
It's like the timing on an engine...improper buffer weight can result in too early or too late timing for the bolt unlock/opening and bcg cycling.
Here is a good description of what is occurring in AR15s: http://ar15barrels.com/prod/operation.shtml
AR15 Buffer Weights
Standard Rifle - 5.2oz
Standard Carbine - 2.9 - 3.0oz (different sources)
H - 3.8oz
H2 - 4.6oz
H3 - 5.4oz
Colt 9mm - 5.5oz
RRA 9mm - 5.6oz (seen elsewhere as 5.4oz)
Enidine Carbine - 4.25 ounces plus three pounds of hydraulic force
Spike's Tactical T2 - 4.3oz
MGI Carbine- 7.1oz
It's like the timing on an engine...improper buffer weight can result in too early or too late timing for the bolt unlock/opening and bcg cycling.
Here is a good description of what is occurring in AR15s: http://ar15barrels.com/prod/operation.shtml
AR15 Buffer Weights
Standard Rifle - 5.2oz
Standard Carbine - 2.9 - 3.0oz (different sources)
H - 3.8oz
H2 - 4.6oz
H3 - 5.4oz
Colt 9mm - 5.5oz
RRA 9mm - 5.6oz (seen elsewhere as 5.4oz)
Enidine Carbine - 4.25 ounces plus three pounds of hydraulic force
Spike's Tactical T2 - 4.3oz
MGI Carbine- 7.1oz