I was curious as to what the "1-7" marking on my DPMS barrel means. My supplier said the barrel is 1/9 twist, does this mean it's actually a 1/7 twist? Any input would be greatly appreciated!
Specs on the barrel:
16" DPMS Preban barrel Cal 5.56
Here's a picture:
That is a heavily oiled up 1:7 twist barrel.