What's Normal for Throat Erosion ?

[67rschev]

Just a question for you all that have been doing this for a lot longer than I . My precision 308 has around 1800 rounds down range in the past 2 1/2 years . It still is just a hammer , and wouldn't trade it for the world . I've been keeping an eye on how far the lands have moved , and after these 1800 or so round the throat has moved .020 to .025 " . Its a 700 with a stainless Obermeyer 5R .298 tight bore . When I first started loading for the piece , I was loading a little hot , chasing some speed and was really zinging them . Found a great node at 2900 + . Got a little tired of using up my brass in 6 loadings , and we all know how scarce brass was the last year so the past 800 or so rounds , I backed off a few tenths . Found the loading was just as accurate at ~ 2860 , and the primer pockets are lasting much longer . My question is does this sound like normal erosion , or excessive to you all ? I have never spent so much attention to detail with loading for any of my guns till this one , so I never paid attention to land movement . Have used Varget exclusively and load .015 jammed for best results . Like I said , its still a sub .5 gun on an average day , and will print even better when I'm in the zone and the gun is on .

[C Ward]

Every barrel is a little different and the hotter the ammo the faster the wear but that sounds reasonable . Most 308's go 8 - 10 K but the Palma guy's , running fast ammo are around 4 K .

What method are you using to measure the throat ? With the Stoney Point / Hornady gauge you need to use the same bullet start to finish not just the same kind because of manufacturing tolerances giving different ogive lengths bullet to bullet .

[TheBelly]

Unless the accuracy starts to degrade, then I wouldn't change anything.

Once the bullet tells you that you need to change things, THEN start to change things. I've seen a 308 barrel with no rifling in the first several inches of barrel, but the thing can still shoot half MOA all day. (not my rifle, a loaner that I had the joy of using).