Measuring throat erosion.

[Firearrow]

So I was told by an "expert" yesterday that I was measurig throat erosion wrong. I have been using my modified Hornady case and the COAL tool to measure my distance to lands, and then doing it again after 250 shots and comparing them.

So am I doing this right? Funny thing was the "expert" wouldn't educate me on how to do it correctly.

 

[tbrice23]

Thats how I do it. I don't know any other way. That expert must be a genius.

 

[Browninglover1]

You could always do this... It's a little more permanent though lol

 

[Canadian Bushman]

Thats how i check throat erosion.

Not everyday you see a barrel cut it half.
I bet theres a lot to learn looking at that.

 

[Barrelnut]

So I was told by an "expert" yesterday that I was measurig throat erosion wrong. I have been using my modified Hornady case and the COAL tool to measure my distance to lands, and then doing it again after 250 shots and comparing them.

So am I doing this right? Funny thing was the "expert" wouldn't educate me on how to do it correctly.

That's how I do it.

Also make sure you are using the same physical bullet each time. I keep the bullet with the modified case.

 

[Browninglover1]

Thats how i check throat erosion.

Not everyday you see a barrel cut it half.
I bet theres a lot to learn looking at that.

That was my Remington VLS 22-250 after 5k rounds. I lost the ability to load to the lands around the 2k round mark; the bullets couldn't stay in the case and reach the lands. It's was pretty cool to see it once I got it sectioned.

 

[Mikecr]

Curious, why would you need to actually measure erosion?

 

[FearNoWind]

I use the same bullet along with the Hornady OAL gauge to get an approximation of throat erosion but I think casting the chamber would provide more accurate data.

Curious, why would you need to actually measure erosion?

The distance to lands will increase as throat erosion increases.

 

[Mikecr]

The distance to lands will increase as throat erosion increases.

Why would you care what that distance actually is?
All that matters is best(as tested) CBTO.

 

[Firearrow]

Curious, why would you need to actually measure erosion?

Here is my thought process on why. I have been told that at around 1000-1200 rounds a 300 WM barrel will be "shot out". To me this means not being able to hold a .50 MOA group ETE. If for some reason my groups open up for some unknown reason I have refrences to check. For example temp to Vel differences, number of shots between barrel cleaning, amount of shots on the cases, ect ect.

I usually blam me for a bad string, or a bad day out at the range. But that doesn't mean that I won't go back and check a few things, and if my barrel likes a jump .09 and now because of throat erosion my jump is now .011 or .012 if have something to look into.

I know this might be way OCD for a guy who loves to hunt and is in no way shape or form a BR shooter. But if I am going to take long range shots I owe it to my self and the animals I am shooting at to know my bullet is going to hit its mark and make a quick kill shot. As long as I do my part, wink wink.

 

[FearNoWind]

Why would you care what that distance actually is?
All that matters is best(as tested) CBTO.

If your favorite load includes a jump of .005 and you experience throat erosion of .010 your jump to lands is now .015. As throat erosion progresses I generally find that I need to adjust my load to account for the variations in distance to contact with lands.

 

[Firearrow]

You could always do this... It's a little more permanent though lolView attachment 43461

As soon as I can get some good bubble gum and duct tape I will get my Dremil out and give it a good look.

 

[Dgd6mm]

If your favorite load includes a jump of .005 and you experience throat erosion of .010 your jump to lands is now .015. As throat erosion progresses I generally find that I need to adjust my load to account for the variations in distance to contact with lands.

Kenny Adams adjust bullet lenght and load after every match. Too some that may be extreme, but it works for keeping your accuracy to your load on target. Throats are eroding every time you squeeze the trigger, some barely, some more, and some a lot.

 

[dkhunt14]

If your rifle shoots best at 10 in the rifling and your throat moves 12 you will lose accuracy. Some cases like the 300 Weatherby IMP would move as much as 30 thousandths in 170 shots. I always check my guns by steelwooling a bullet and looking at the marks. Some other guns don't hardly move at all. If you are a match shooter you need to keep after it if you want the best accuracy. Matt