- be fine for walk-and-pastes?

From what I hear, it sounds like with the same 75/77gr load, it should shoot MOA or less to 200yds for another 3000rds, but magically opens to 3-4 MOA at 600yds.


I'm trying to figure out if someone actually has an equipment issue, or just needs "special tires" to help them mentally. A high SS with consistent scores of either 160s on windy days or 180s on pleasant days, and mostly vertical stringing makes me think they're just having difficulty with irons.

As the throat erodes it starts getting cracks in it. That's the only way I can describe what it looks like in a bore scope. These cracks can effect the jacket of the bullet enough that long range accuracy suffers. Sometimes JB paste can bring some life back into the barrel. Otherwise it's just a fact of service rifle shooting. 3K is all I have ever gotten before flyers at 600 start. You can be banging away with 10's and X' and suddenly a 7 comes out of nowhere.

Frank

Attached File

Also a function of gas blow-by as the throat advances.  Around 3,000 rounds I'd have two groups in 300 rapids with different centers, and un-called flyers out of nowhere in the 7, 8, and 9-rings at 600.

About how much advance?

I don't specifically remember but maybe a hundredth per thousand rounds.  I burned out a stainless Douglas/Marchant Brownells barrel at around 3,000 rounds.  I've seen other guys burn out ER Shaws at a whole lot less.

Chrome Moly or stainless?

The first barrel I wore out was a CM Douglas in a Compass Lake upper.

I had shot a personal best of 7511 on a Saturday and the next Saturday, I had trouble hitting the target.

I found the throat had eroded far enough that an 80SMK touching the rifling was no longer in the case. 2500 rounds.

I went to SS and never looked back.