Found a split in the barrel and choke

[Ram Ringer]

I have a Rem870 Synthetic Supermag Express chambered for 3 1/2" shells. I noticed it has a slight 1/4" long split starting at the muzzle. I removed the choke tube and it is split all the way down one side. I mainly shoot steel shot through the gun. The gun is less than a year old. The choke is a Remington full choke designed to use both steel and lead. It is several years old and has seen thousands of rounds put through it. I am wondering if the choke wore out and in the process of it cracking caused the crack in the barrel. Any thoughts?

[Synchronizor]

I'd agree, it sounds like the split choke tube was flexing during firing, stressing the thin metal on the end of the barrel and cracking it.

Chokes may be rated for steel shot, but that stuff is still hard on them, so if you're a high-volume shooter, they should be inspected frequently and replaced when appropriate. The loads you were using may have also caused accelerated wear. Most manufacturers advise against using steel shot above certain sizes and velocities in their steel-rated choke tubes with full or tighter constrictions.