Interesting info from James from Shoten Armory:

While the enclosed (attached) photos are obviously of Mossberg 500 barrels, we
receive the same results from our ported Remington barrels as well. You will
notice I did not specify a length. The barrel by itself is a 20″ and the two barrels
together are set up differently. One used to be a 28″ vent rig reduced to 18.” and
ported by Shoten Armory while the other is a stock 18.5″ Mossberg barrel with
Mossberg heat shield with Shoten Armory porting and bead front sight.

While we have Remington barrels set up the same way, we do not have suitable photos
that would allow you to see the tight and clean machining we did and the fact that
we actually use a multiphase drilling and deburring process inside and out to insure
zero tooling marks.

It is important to note a number of things here:

1) We do NOT backbore the barrels. Doing so does affect spread pattern of shot but results
in a drastic reduction of slug accuracy.

2) We are able to show up to 65% reduction in muzzle flip in an 18.5″ barrel using either
00 Buckshot or slugs.

3) in most cases, the wall thickness of Mossberg barrels is generally thicker than Remington.
Meaning, a lighter weight barrel is more prone to flip than a heavier weight barrel. The Remington
LE barrels are heavier and are far more comparable to Mossberg. I’ve run calipers on all of my
barrels and generally, the Mossbergs are heavier and with more substantial wall thickness. Still, the
porting results we have seen on Remington barrels have been very comparable in keeping with the advertised 65% maximum muzzle flip reduction we’ve been receiving.

I can easily go into more depth here from an engineering standpoint, but from a shooter’s standpoint, they are more interested in end results in their hands.

Barrel Porting

Barrel Porting