28 Nosler throat erosion 😳😳

This is from my dads rifle. I've loaded for it since the very beginning. It's been shooting 155 Hammer Hunters with 84gr. of N570 for about 200 rounds. When the gun was brand new I checked the jam on the bullet (case on the left). I've been chasing a steep velocity drop lately, so I decided to recheck it by jamming another bullet. .236" of throat erosion in right around 200-250 rounds 😬😬.

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Speed of said load?
 
Speed of said load?
Started out at 3350FPS, then it was barely hitting 3250FPS before I did a new assessment. I have no doubt I can just bring it back up to speed now that I know what's going on. Probably just seat them .150 longer and add 2 grains of powder and it'll be right back in there. But for now I have a fresh 50 loaded up at the original charge weight and seating depth. Still shoots good though.
 
Same lot of powder when going from 3350 to 3250?
Yeah it is. I had the exact same thing happen on my own personal 28 Nosler also. At around 400 rounds I started with 169 Hammers with 83gr. N570 at 3300FPS. By the time the barrel was shot out around 800 rounds, I needed 88gr. of N570 to maintain that speed. And a 169 hammer wouldn't even fit inside the case neck and touch the lands.
 
Understand, I've worked my way thru multiple 7 Mashburn Super barrels and there is a history of chasing lands and losing some speed.

Price we pay for driving a race car I guess
 
This throat erosion thing is an interesting phenomenon. The heat of the powder I'm sure has an effect although the actual difference between the powders in the chart was interesting to me. This flame cutting process is impacted by so many factors. Duration and temperature seem to be the primary contributors to erosion. It is beyond my understanding why a 28N can be shot out in less than 800 rounds and some chamberings can last several thousand shots of high temp powders. Oh well, every little thing adds up I guess. As many have stated it is the price we pay for performance.
 
Of interesting side note, while the 28 Nos is about 100 fps or so faster than my beloved 7 Mashburn Super it has way less barrel life!

I'm hearing plenty of chatter about 28 Nos barrels being toast sub 1000 rounds.

Over the last 3 decades I've been thru multiple Mashburn barrels and they generally begin to foul a bit in and around 1700 rounds, accuracy stay fine and shortly there after I begin to chase the lands a bit. I've had plenty good speed and accuracy to over 2500 rounds.

Guess one would have to ask is the extra 100 fps or so really all that worth it....just a thunk eh
 
When your barrel starts to go south, you'll occasionally get a flyer, not consistently, but maybe 1 out of 6 or 7 shots. It'll be the one you swore was a good hold.
 
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