Now check scatter values, MP-41 has better barrage.
ROF of MP-41 on barrage is 6.95
ROF for grw34 on barrage 5.5
that is 126% not 300% as you claim
https://coh2.serealia.ca/#67
Reload duration on barrage
ROF MP-41 3,58 sec
ROF GRW34 1,25 sec
So MP-41 dont have better barrage as you said?