Everything being the same with the load , weighed charges , same bullets , same COL , Same Primers , same Brass ( LC ), two twist rates , side by side comparison . Why would a a 1-8 be faster then a 1-7 at one velocity , but slower at a higher velocity , they were different Powders used , but why would that have anything to do with it . The side by side comparison in the first test with TAC Powder the 1-8 avg. was 25 fps faster then the 1-7 twist , then with a different Powder ( Xterminator ) with a larger Powder charge , do a 180 & switch the 1-7 having an avg. velocity of 43 fps faster then the 1-8 twist .
Is it the Piston system with the atmospheric discharge using less gas to operate the Action properly or efficiently ( because its adj. ) meaning more gas is actually staying in the Bore , behind the Bullet , then the DI system that is fixed orifice & the wasted or excessive gas is going into the Upper Receiver ?
Both Barrels are 16" , Mid Gas systems , the 1-7 is Nitrated & the 1-8 is Stainless steal , both about the same round count . ( low ) 1-7 a Piston system. 1-8 a DI system .
Thoughts ?