I am going to start this by setting the context. The barrel is a 26” Rock Creek 1-8” twist MTU contour 5R, chambered in 6.5 Creedmoor. The large majority of rounds fired through this rifle were the Sin City Precision team load. The load is fairly mild and is by no means a “hot” load. We shoot practical precision rifle matches so some of the shot strings are long (up to 20 rounds in a single stage) and the barrel gets very hot. We use our rifles in the manner they were meant to be used, but do not go out of our way to abuse them.
We do not often bother with setting a barrel back. We try to keep fresh barrels on our competition rifles and reuse old ones for different projects or just general tinkering. We also do not bother chasing the lands and adding powder to the case. When we say barrel life, we mean how many rounds your load will shoot before the throat erodes to the point it causes a significant loss in velocity. What is a significant amount of velocity? We consider 100-200+ fps a significant loss. The velocity loss is enough to cause a miss because your bullets a dropping more than normal. You can also experience a loss in accuracy because the amount your bullet is “jumping” to the lands increases. Both, setting back a barrel and chasing lands will allow you get get more rounds on the barrel. The barrel will eventually die.
Bill let his barrel go a long way and mainly because it still shot well, the velocity loss was not very noticeable. It is also difficult to identify if small changes in DOPE are cause by atmospheric conditions or a velocity loss. I do believe though, the barrel was no longer shooting as consistent then when it was new. What I mean is Bill would shoot 3 rounds. Two of the rounds would be on top of each other, with one slight flier. He shot multiple 3 round groups and we noticed this with a couple of them. Overall the rifle still shot really well. Despite this, a new one was long overdue.
Now for the meaty part, barrel life, barrel life, barrel life. Everyone wants to think you are going to shoot a 6.5mm cartridge and get .308 Winchester barrel life. I am here to tell you that is not true what so ever. Not in the least bit, not for the type of shooting we do. On average a 6.5 Creedmoor shooting factory ammo will die at around 2,000-2,500 rounds. We have noticed some barrels do better than others and make it past the 2,500 round mark. We attribute this to the barrel hardness. When cutting them on the lathe you get a feel for the material. Some barrels like Benchmark, Lothar Walther and Krieger are notably harder than others and have better barrel life. Rock Creek and Bartlein seem a little softer and usually only make it to the 2,000-2,200 round mark. (I do want to add all the mentioned barrels exhibit awesome accuracy)
As you can see from the example we have provided here, the throat is beat. The free bore has been greatly extended, and over the course of its life the load went from jumping 0.002” to jumping A LOT! New systems are coming along like carbon fiber wrapped barrels from Proof Research and the Straight Jacket system from Teludyne Tech that are supposed to extend the barrel life of these high performance cartridges by removing heat. Which one is better? I have no idea honestly. I think time will decided which of the two mentioned products, is the real deal. I believe it is very possible they both are the real deal.
Barrels are a consumable product. They are going to wear out. The more you use them the faster they wear out. Treating your barrel like a set of brake pads is the best way to look at it. If you mainly drive on the highway using the cruise control, your brake pads will last a long time. If you take your car out to Spring Mountain every weekend and bomb around the track, chances are you are going to wear your brake pads very quickly. Because of the volume and manner we shoot (long shot strings, high round counts) our barrels do not last as long. Could you get 3,000+ solid rounds from a 6.5 Creemoor? Sure, I imagine that barrel is going to be babied like a new born but it is plausible.
What did we learn? We are NOT shooting .308’s. Your 6.5mm barrel is not going to go 5,000-8,000+ rounds. The performance you gain comes at a cost, and that cost is barrel life.