Throat erosion

Throat erosion is mainly a heat thing. The more powder the faster it goes. Some calibers are notorious like 243 for eating throats. The larger the overbore the worse off you are.

See any fire cracking yet?

264 win mag is another

That sounds excessive to me. What kind of loads are you running?

Did you keep the same test bullet and cartridge

From what I’ve read, ball powders tend to erode throats less than stick. The military seems to think so as well.

BreechFace said:

From what I’ve read, ball powders tend to erode throats less than stick. The military seems to think so as well.

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Shape means very little. Single base vs double base is the ticket.

From what this PRB post documented, it appears a little faster wear per 100 rounds than typical *competition* use...But not too far off. Unfortunately the article does not have 6.5 creedmore data (does have 6.5x47 and 6.5-284)

https://precisionrifleblog.com/2020/03/24/how-fast-does-a-barrel-wear/

JCSC said:

I have run a handful of loads, but all have been with H4350. Nothing above the 41.5 gr max with 140 hpbt.

no fire cracking that I can see, but I don’t have a note scope anyway.

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How much time between shots? A hot barrel supposedly burns out faster.
I don't know because I only shoot slowly when target shooting.
Wear it out and re-barrel

I've heard of people that buy enough brass to last the life of the barrel. When the barrel needs replacing, they ditch the brass too, and start over.

That's not excessive for 6.5 CM. You will only get about 3,500 rounds before the barrel will be shot out. Be glad its not a 6mm. Then, you would then be replacing the barrel after about 1,500 rounds.

Think about throat erosion and changing where the lands actually are after erosion. IMHO If anything is going to throw off best seating depth for your rifle, it is the erosion.

Some that chance the lands will cut the barrel back 1 thread and ream back to spec. This buys them a little more time. I prefer to use a bullet that likes the jump so your not adj the length on every batch of ammo you do.

AJC1 said:

Did you keep the same test bullet and cartridge

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I think this is really important - most especially with an extreme overbored cartridge which may only get 1,000 rounds before accuracy starts to erode. Get an accurate headspace and max COAL measurements on your rifle chamber when new and keep those measurements safe. On used rifles, take the measurements and watch the progression. I'm lucky to have a gunsmith friend with a borescope (and a lathe and a mill, etc.). Good gunsmiths with good borescopes are hard to find at least around here.

AJC1 said:

Throat erosion is mainly a heat thing. The more powder the faster it goes. Some calibers are notorious like 243 for eating throats. The larger the overbore the worse off you are.

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If it's a heat thing, as I have heard. Open your bolt and let the barrel breathe and slow down your shots. Letting the barrel cool a bit. This can help, I believe.

7mm Rum is Notorious for it. In researching mine I found the best way to extend barrel life is to let it cool and also run a cleaning patch down it after the 5th round or so every time you shoot. My cousin has a battery powered air mattress pump set up to blow air down the barrel of his 6.5 Creedmoor to cool it down between shots.

My various 204 and 20 practicals only make it around 2000 rounds. My son's 223's groups started opening up around 2700 rounds. My 270 was starting to go around 1500 rounds, but note 300-400 rounds were cast bullets).
From my experience 223's go around 3000 rounds for prairie dogs, that is 1 MOA or worse to rebarrel.

Sad thread, just for my own info: I'm having a new Lilja barrel installed on my old trusty 22-250. 1-8 twist for 70 - 75 gr match bullets. Wonder how many rounds it will take to lose some degree of accuracy? Rifle is being built for a Ground Hog / Egg Shoot match in NC first Saturday in April 2021. Guessing around 3000 fps for the loads, or maybe a little more. Depends where the sweet spot is.

Throat erosion is combination of several factors with Heat and Velocity being the big 2. The reason magnums are the first to give up, is more powder and the longer burn time. This gives you both heat and velocity moving over the highest heat area repeatedly. I don't like powders that run HOT, this just shortens the barrel life. Think Little-Gun, not recommend for revolvers but ok for Rifles? Same heat just not allowed to leak, so it's going to shorten the barrel life. Another powder is TG which runs hotter than blazes, mainly used is autos. I shot out a SS 223 Wydle chamber around 7000-8000 rounds trying to get it to shoot the light bullets. The barrel won, never did get it to shoot, replaced with a Shilen barrel. I have a brand new Kreiger Ultra Match barrel ready for my Match gun 223R which currently has 5300 round count. Reminds me I need to order some more barrel blanks to have on hand.