Do Velocity, SD and Accuracy Drop at End of Barrel Life

[Catfur]

1100+ rounds ago (using the same bat primers and the same bat jug of powder), my 6XC load shot 3030fps, SD of 6 and nearly .35" Avg groups. Now (probably 30F temp difference), the same load shoots 2935fps, SD of 14 and .7" groups. Barrel was not new when re-chambered for 6XC (probably had ~500 on it).

Is this normal behavior at the end of the barrel life?

 

[fgregorio]

It is, but it feels too early in terms of round count.
Try not cleaning the muzzle crown for say 100 RDS and have a look at the fouling footprint.
A barrel in good condition will print a tiny triangle in front of each land and nothing else.
If you have a worn out barrel you will find those triangles to be bigger and you'll find some fouling between the triangles. It looks like hairline cracks shaped out of powder fouling.
If that fouling between the triangles is a touch more than that, my suggestion is to stop cleaning the barrel. Beyond that you could try honing the first few inches of the barrel. Check out the thread " extending a barrels accuracy life by honing" or something like that.

 

[dkhunt14]

It is possible the temperature difference threw the load out of its node. When my barrels start to loose their edge I see shots leak out of the group. Usually it is vertically. I have had barrels go at 500 rounds and have others go at 1100 rounds. Now I shoot 1000 Yard BR and need great accuracy. The way we shoot them by firing fast hurts the throat. It also depends on what powder, what barrel, rate of fire and what cartridge. Some just last longer then others. It also depends on what level of accuracy you want or need to compete. Matt