CZ 457 Borescope - 6 Months Later

I've shot nothing but CCI Std Velocity. After shooting, I pulled through 5 patches until they came out clean. No lube or cleaning supplies.

[arlxen]

The lands aren’t chewed up, it’s just lead. It builds up over time.

[jonleone]

Whats up with crown area. Looks a bit chewed up.

[nelsonm]

the crown i horrible... prob 90% of the issue... my MTR crown is sharp and clean! shot amazingly well.

[malbirrell]

Interesting damage to the lands just inside the muzzle. Piloted crown tool ?

[PeakyBlinder]

There is no step from the chamber to the lands,
I'm sure my barrel was ported incorrectly.

[michaelhill]

What are your 50 and 100 yard groups like with the CCI SV? You need to do some serious carbon removal starting at your chamber, thats a lot of carbon buildup.

[caseysetsodi]

How do you get a barrel that clean? What are you using?