I had some problems with the 225's but my 30-375R barrel had 1600 rounds through it.
I made a lot of hits at ELR distances on day one, didn't clean the barrel, and on day two the vertical was horrible.
Got back home and cleaned the barrel really thoroughly and the rifle shot good again with the same load and box of 225's???
Bullet rpm to an extent in some calibers is going to go up. Longer bullets usually need a faster twist, velocity plays a part but it’s only a part of it.....
A 308 win at 2700fps in a 12 twist barrel the bullet is coming out at 162,000rpm.
A 6mm that needs a 8 twist and lets just say the bullet is also coming out at 2700fps is spinning at 243,000rpm. This same silly little 6mm bullet at 3000fps is spinning at 270,000rpm.
And we all want faster right?
Now lets factor in Steve123 post about cleaning....we’ve been saying for a while that especially with over case capacity for bore size cartridges you have to keep up with the cleaning. Pick a round count or even say the frequency of cleaning. A shooter who doesn’t keep up with the cleaning and doing it properly how do you put the bullet maker on the hook for bullet failures let alone the barrel has a ton of rounds on it?
One of the guys in the shop was at a match last year....was scoring a shooter two different days. The shooter shot both F open and FTR. The open class gun was a 6.5mm and the FTR gun was a 223 Rem. He shot one brand of bullet in the open gun and a different brand in the FTR gun. Both rifles where blowing up bullets and the shooter was cursing both bullet brands. After he talked to the shooter the 6.5 had a round count in the area of 5k rounds and the 223 gun had in excess of 9k rounds. Dude the barrels are toast! Not a bullet problem in that case.
I recently had a nice conversation with two different bullet makers and we all agreed that approaching 300,000rpm bullet failure is going to go up. My comment was I draw the line in the sand and it’s 300k.
I’ve got a barrel in 6.5CM on a rifle and the twist is 1-6.75 and I have 147 Hornady’s and 150SMK and 153 ATIPs coming out at an honest 2700fps. The rpm is at 288,000. I’m shooting 135ATIPs at 2800fps and they are coming out at 298,666rpm. The barrel only has 300+ rounds on it as of right now. I’d have to double check my log book to be exact but I have had no bullet failures at all. I’ve shot the gun out to a 1k yards. I’ve also shot box Hornady 140ELDM’s with no issues but only out to 430 yards I’ve shot those.
I do feel I’m on borrowed time barrel life wise before failures will start to happen. I’m going to throw a round count of around 1200-1500 rounds is when it will start to happen. So your thinking why did I go with that fast of a twist? There where new bullets coming out and we where all guessing to some extent what twist was going to be needed to stabilize them. The thought was a 7 twist might not be fast enough. That’s why I did the 6.75.
Now throw in the guy that says....Hey 2700fps out of a 6.5 isn’t fast enough so he has to have a 6.5 that will throw that 140gr bullet @ 3400fps! He needs/wants faster/flatter/buck the wind better velocity etc.. but even in a 8 twist that’s giving you 306,000rpm. Guys are doing it but like I said how do we put the bullet makers on the hook when a bullet fails?
We all at times are pushing the envelope and have to sit down and take a look at what really is reality.
Later, Frank