Switching to H4831SC or even better H1000 for the 243 would lower peak pressure for the same velocity and likely increase bore life.
I have never shot these but there are some wildcats based off the 243 and 6mm Rem where H1000 is the fuel of choice and they report much better bore life. Certainly the science makes sense... how practical it is, I cannot say.
H4350 is a wonderful powder and I burn buckets of it but like all other Extreme powders, they can become very erosive once you go past magnum pressures. If both peak pressures are the same (243 vs cm), the fact that the 243 must burn more fuel would certainly cause more wear and tear.
BUT if you drop peak pressure substantially using a much slower powder, the bore temp is dramatically cooler and thus erosion can be much less. You aren't going any slower because you have so much more fuel to push on the bullet.
Fouling could go way up but we can clean our barrels at the end of the day.
SO..... just depends
Jerry
Hard to get enough h1000 in a 243 case and have competitive velocities.
4831sc pegs out around 3000 fps at 60,000. Same velocity in the 6 creed at the same powder charge. But as I mentioned, guys are seeing less erosion when using the same powder, theoretically due to shoulder angle.
Seems like a stretch to me, but what do I know ?




















































