I'm of the opinion that since the flame is 'different' between the flat base and boat tail bullets, that the throat erosion should be 'different'. Whether the difference is noticeable in the real world and whether its worse for flatbase or for BT bullets???
That above statement from AJ is so very true. And lets say this posts goes on for 2 years and has 1000s of replies. In the end it will still boil down to the above statement. In theory there is a difference, but in the end does it really make a difference in barrel "life". no
To expand on this a little, myself and a couple close friends who are big into long range BR shooting have done many experiments and one of our latest is shooting flatbase bullets in 600 and 1000yd BR competition. It a long story as to why, but something we wanted to try and test out.
Anyway, the test started out great. The first 6.5 140gr FB bullet design started shooting like a house-a-fire and won the first match out. We had a lot of success and no problems for awhile. Time goes by and these bullets started comping apart in flight and I ended up with several DQ for insufficient impacts on the targets to be scored.
When we ran into the bullets coming apart problem we talked with another long range competitor who is also a mechanical engineer by trade and has his own Oehler M43 permanetaly setup in his backyard shooting range. He informed us of some of his own experiments with his own 6mm FB bullets that came apart and showed comet tails on 25yd targets. He took a lot of 6mm FB bullets that would come apart in flight and cut a 3 degree boattail on the bback of them and they quit coming apart as often. He used the same barrel, Lot# of bullets, powder, everything on his own range and was able to reduce the number of blowups by simply cutting a 3 degree?? taper on the back of the existing bullet jacket.
That right there says there is a difference in heat transfer/generation between boattail and FB bullets under controlled test conditions. But as was pointed out above what does it really mean in the overall life of a barrel? I keep exact records of all of my competition rifles. I can't tell the difference in barrel life between the two bullets. The throat goes out first in a barrel and I beleive it has more to do with temperatures and pressure more than anything mecanical in the bullet.
Or to state it another way... what is the quickest way to burn out a barrel? Shoot hot loads at high velocity or increase your sustained rate of fire without a cool down period! And you can do both of the above with or without boattail bullets.