Blow back is just old school. Good when it was out.
MPX with gas ports is the future for 9mm PCC.
I have had two MPXs never had an issue with either one.
MPX- 16" vs 8" barrel- what one will create more gas pressure at the comp?The 16" factory barrel,
or the 8"' factory barrel- I will be using the 2.5" comp from the new 16" carbine barrel.
For anyone that has the new carbine with the 16" barrel- thread pitch IS
M 13.5L same as their 6 and 8" barrel's
Doubled checked with two Sig gunsmiths at the Exeter NH plant.