MV related to round count

[dunraven]

What typically happens to MV as round count increases toward the end of expected barrel life? Can this help predict the end of a useful barrel? Thx.

 

[Dusty Stevens]

No correlation. Target tells the tale

 

[rwj]

No correlation. Target tells the tale

“Darn” flyers!

 

[Dusty Stevens]

“Darn” flyers!

RDF?

 

[shoot4fun]

What typically happens to MV as round count increases toward the end of expected barrel life? Can this help predict the end of a useful barrel? Thx.

Sounds like you’ve talking to the PRS guys.

 

[Big_Daddy]

What typically happens to MV as round count increases toward the end of expected barrel life? Can this help predict the end of a useful barrel? Thx.

I wish it was that easy and clear cut....LOL

My old varmint gun has close to 10,000 rounds thru it and while the accuracy has diminished, the muzzle velocity has not.

Your targets will tell you when it is time to re-barrel.
I save pictures, with measurements, of large number of my targets just for this purpose.

 

[rwj]

RDF?

To me, a flyer is a shot that at least doubles the group size and wasn’t called when the shot broke. When they start to appear regularly, not randomly, is when I start planning for barrel replacement. I’m sure that there are other replacement criteria, but I’ve yet to notice any significant change in MV...

 

[Ned Ludd]

There are very clear signs when a barrel starts to wear. The throat and first inch or two of the barrel will start to feel rough when you put a cleaning patch through it, and it will be fire-cracked when observed through a borescope. Not long afterward, you will usually start to see it coppering up at the muzzle much more rapidly. These are extremely overt and obvious signs of barrel wear.

The problem is not that you can't detect such signs of wear, it is that the signs only tell you the barrel is undergoing normal wear, they may or may not tell you anything about when precision/accuracy will start to fall off. I had a .308 F-TR barrel with a little over 3600 rounds on it. It had a very rough throat, was heavily fire-cracked for the first couple inches, and coppered up fairly rapidly. Nonethless, that barrel shot cleans with good X-counts in 3 out of the last 4 F-TR 600 yd matches where I used it. If I hadn't run out of the Lot # of bullets I had worked up the load with, that barrel would likely still be on that rifle. So there is no magic warning light that tells you when a barrel will stop shooting with good precision, even though it should be pretty obvious when the throat area starts getting heavily worn.

 

[xswanted]

I had a 20-250 I shot out a few years back.

55s at 3700 FPS.

Shot great all the way until it was done. Velocity was consistent.

When this barrel went, it went fast. Missed a coyote. Then hit him with a follow up. This happened a few times over the winter.

Shot some groups to verify and after the fifth or sixth shot that day I had a bullet go through the target near sideways.

At this point but no time before was the only tome I saw erratic velocities.