Throat erosion question

[TroyMN]

How much would you expect from a .223, 24.5 RL15, 80gr Berger VLDs, 2890 fps. Over about 500 rounds it looks to be .021, seemed high?
Most shoots have been once each 2 minutes to keep barrel from getting too hot. Last 180 rounds were F-class at 80+ degrees (22 rounds in 10-15 minutes).
Thanks for your input.
Troy

 

[rminut]

considering some people find that after .050 of wear a barrel can go south at anytime, it might be considered fast wearing. The bigger factor is that the wear is even on all the lands/grooves, if it's even the barrel can last very long compared to uneven wear. some say that double based powders like RE15 can cause more wear.

 

[DIBBS]

I wouldn't worry about throat erosion, shoot it until it no longer meets your accuracy standards/needs, then rebarrel. Barrels are part of the "consumable item portion"of the various shooting venues we enjoy, and wear out at varying rates depending on rate of fire, powder burned, type of powder etc. Hopefully you can chase the lands for a bit as the throat erodes/wears, and when accuracy goes south, put a new tube on.

 

[fdshuster]

Also depends on the type of bullets used. Those long 80 grainers will wash out a throat quicker than 45 to 55 gr.. I used to get a ittle over 4500 rounds out of an AR barrel when using the "little" 50 to 55 gr., then started using more of the 80 gr. SMK's. Barrels were done around 3000 rounds fired.

When I say "done" i mean they would not hold MOA any longer, bad enough that they could not be used in a match. Want to hit tin cans at 50 to 100 yards? Sure they will do that but nothing more.

 

[lpreddick]

interesting... throat erosion as related to bullet weight. i'm under the impression that lands erosion is more a factor of HEAT and actual burning of the steel..i see dried creekbed and longitudinal cracks in the lands with my hawkeye. go further in the bore and the lands are perfect...the same bullet went through this entire bore. i read elsewhere that powder burn rate may have a greater effect on lands erosion than the bullet's weight. heavier bullets are usually propelled by slower powders and the lighter ones go with the fast powders. granted, some cartridges are notorious for erosion regardless of powder burn rate...the .243 comes to mind here.

 

[spclark]

How much would you expect from a .223...?

Your numbers seem a little high compared to what I'm seeing in my stuff. What brand of barrel? Some are reported to stand up better over time.

You may see the rate slow a bit now that your barrel's well broken-in though I'd keep an eye on it.

 

[GrocMax]

I bet if you factored in bearing surface length between the 55's and 80's and number of rds to 'bad tube' the resulting number would be about the same.

Bullet brg length x rds fired.

interesting... throat erosion as related to bullet weight. i'm under the impression that lands erosion is more a factor of HEAT and actual burning of the steel..i see dried creekbed and longitudinal cracks in the lands with my hawkeye. go further in the bore and the lands are perfect...the same bullet went through this entire bore. i read elsewhere that powder burn rate may have a greater effect on lands erosion than the bullet's weight. heavier bullets are usually propelled by slower powders and the lighter ones go with the fast powders. granted, some cartridges are notorious for erosion regardless of powder burn rate...the .243 comes to mind here.

 

[skiutah02]

Troy,

Here is some data that may help.

223 90gr 250 rounds fired (50 of which were at same time as you during a MN match), 0.001" erosion (1st measurement was after 1st 20 shots)
308 155, 178 and 185gr at 1000 rounds 0.006" erosion, now at 2700 an additional 0.009" (80+ at same match as you). Drew

 

[jsthntn247]

considering some people find that after .050 of wear a barrel can go south at anytime, it might be considered fast wearing. The bigger factor is that the wear is even on all the lands/grooves, if it's even the barrel can last very long compared to uneven wear. some say that double based powders like RE15 can cause more wear.

Funny that you mention this. I proposed a question on the reloading section earlier this week and got hardly any response. Folks acted as this made no sense. I've noticed that two of the 5 lands are .020 longer. I can no longer shoot bullets off of all of the lands without getting horizontal dispersion. I have to soft seat bullets .040 to get rid of the horizontal. When the barrel was new and all lands were square, accuracy was phenominal .015 off. I proposed that the uneven wear was causing the horizontal dispersion because the bullet was contacting the lands unevenly and when jammed, the bullet was centered.

 

[lpreddick]

absolutely! i determine the distance to the lands by seating a bullet slightly long and chamber. a buffed bullet(4-0 steel wool) with overhead lighting will show the land's engravings and when new, these marks are square and equal...most of my barrels are 4 groove. after many rounds, the marks become thinner and rounded and as i back the bullet out of the lands, one will disappear. move back a few thous and only 2 remain, then none. a jumped bullet will obviously enter the lands off balance and may well affect accuracy. "touching" is now risky, but a good "jam" should help correct this discrepency.

 

[gdc/dc]

My 9317 got to hittin everywhere and nothing helped. It had 10k plus thru it. Prairie dogs were its time spent. Sent it back to savage and the report from them was throat erosion. Twas a SS barrel bull . I traded em for same gun .was happy with them. J.c.

 

[jsthntn247]

absolutely! i determine the distance to the lands by seating a bullet slightly long and chamber. a buffed bullet(4-0 steel wool) with overhead lighting will show the land's engravings and when new, these marks are square and equal...most of my barrels are 4 groove. after many rounds, the marks become thinner and rounded and as i back the bullet out of the lands, one will disappear. move back a few thous and only 2 remain, then none. a jumped bullet will obviously enter the lands off balance and may well affect accuracy. "touching" is now risky, but a good "jam" should help correct this discrepency.

This is the gospel truth!!

 

[6fatrat]

Keep shooting and enjoy. Don't worry about the throat , the accuracy killer is the fire cracking that occurs in the grooves in the first 1 to 2 inches of the barrel. My space gun shooting mag length ammo jumping .09+" shot a 200 with 14 x's at 600 prone last fall. The uneven throat erosion, cleaning rod wear???

 

[TimP]

There is a good chance there was a little reamer fuzz left behind and your initial measurement was a little skewed. Check after the next couple hundred rounds and see if it hasn't settled down.