I was wondering how many shots it takes your guns throat to move lets say .010 lets say the gun is a 30-06 also another case could be a 7mag. I know there area lot of variables, I am just looking at typical conditons

CC,

In my experience with shooting a lot of pds, erosion is not linear in progression. It starts slow, and then gets worse quickly, as the throat lengthens.

I am finding out the metal used in the barrel can have a lot to do with it also.

In my 22-250 heavy gun, the first .010 lasted about 2000 rounds. Approximately 2000 rounds later it was throated over .050.

My dads 243 at 2000 rounds is approximately .040

Brothers 7mm is .015 at about 1000.

My 300 WM is approximately .020 at 2000.

All guns are shot conservatively. We try not to over heat the barrels, and I use the slowest powder I can get away with.

Jim

I have a 16 year old Browning A-bolt chambered in 338 WM. I have shot roughly 600 rounds through it. This is my best guess as I did not keep precise records.

Four years ago, my accuracy dropped off with my pet load. So I swapped powders and went to a different seating depth which brought things back in line. A few months ago, I used an RCBS Precision Micrometer to measure the distance to the lands. This is the same tool I originally used to establish my initial seating depth years ago.

For some reason in my reloading records, I recorded the lands beginning within a range of .005 rather than a specific point. I must not have been able to get a consistent reading with the tool back in the day. When I measured it a few months ago I was surprised to see my throat had moved forward .007-.012 from the original range. Fortunately, I have more than enough room in my magazine box to accomodate the length needed for accurate shooting.

Hey cc

It is really hard to keep accurate numbers and measurements to the lands can vary no matter what your system of measuring is. That being said I have kept track of my Hart 280AI barrel shooting 160 gr Accubonds with RL22 (the slower your powder the more the throat wear) and after approximately 370 shots my measurements have gone from 3.330" to 3.375" which is .045".

Here are some others from my spread sheet but there are some anomalies and these may not be as exact as I would like them to be:

22-250 - 55 NBT - mostly Varget - 225 shots -2.515" to 2.520" - .005"
30-06 - 200 AB - RL22 - 250 shots - 3.378" to 3.3950" - .017"
300 win mag - 200 AB - RL22 - 800 shots - 3.505" to 3.5885" - .088"

These are the only ones where I have shot the same bullet from beginning till now and the number of shots is estimated.

CC, it's important, if you exactly want to measure the throat wear, to do this in the same way. I use a Stoney Point Chamber OAL Gauge, which proofed to be very accurate to me. When I want to reload a new batch I always measure the seating depth to the rifling about ten times with a bullet of the former batch to know the difference and take the average of the findings. Then I do the same with bullets of the new batch to settle the gap for the reloadings and I save one for the next measurement.
After 265 Gamekings over 60 grains H 4831sc, RWS brass and CCIbr primers, I found a throat wear of .004" in my Sako .270 Winchester. After some 5000 rounds I had to replace the barrel, because I had to place the bullets too far out. I keep exact record of my firings, so I am sure of the number of rounds.
Recently I mounted a Lothar Walther SS-barrel on my Sendero .270 and after some 250 rounds I still cannot find any wear, using 130 grainers TTSX over the same 4831.
Nice day,
Jan