HS Precision Throat Erosion

mosquitoshooter

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Hello all, I have over 1,000 rounds in my HS Precision HTR in 308 and today I noticed with my Hornady Overall Length Gauge that the bullet appears to be .020 longer in order to engage the lands than when new. Throat erosion of .020 basically. It is only six months old and again 1,000 rounds shot through. I have ridden this thing hard in only six months but my question is, is this rate of erosion normal? It seems to be retaining its accuracy but will I need to ditch the barrel soon? Ive heard some say these 308 barrels can go for 10,000 rounds. I am beginning to doubt that. At least while retaining the 1/2 moa accuracy it currently has. Thoughts?
 

jrbet83

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Re: HS Precision Throat Erosion

10,000 is alittle much. 4,000 is a more reasonable match competitive round count.

.020 seems like more than would be expected for a .308 with 1,000, but there's no magic number on how much a throat can grow before accuracy goes too. some guys on here re-barrel shooters, and find out the throat is SUPER long, but was still shooting. others see accuracy start to go, and measure the throat, and it's relatively short. you can only shoot it and keep on eye on your accuracy. sorry for the relatively vague response, but there's no one right answer or cut in stone amount/number.
 

one shot ST

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Re: HS Precision Throat Erosion

Other things to check is.... was correct the first meausure ?
 

Victor N TN

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Re: HS Precision Throat Erosion

Benchrest shooters figure .005" in OAL per 500 rounds. But that's with a 6PPC. Less than half the case capacity of a 308.

Your 308 will still be able to shoot through the same barrel at 10,000 rounds. But it won't be as accurate. Accuracy starts falling off after 4,000 rounds. You can have the chamber re-cut and bumped back. That will add some time to the barrel. But if you have to pay someone to do it, you may as well have a new barrel fit to your rifle.

I have one of my benchrest barrels that has been rechambered 4 times already. It still shoots really well. Remember the crown every time you have the barrel off.

Good luck.
 

shadow4

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Re: HS Precision Throat Erosion

Did you use the exact same bullet to measure your throat that you used the first time.......... if not it could just be bullet to bullet variations. I kept THE bullet I first measured my throat with when I got my new rifle and put it aside for so that I can get exact measurements in the future, and not have to wonder if bullet variation, or lot to lot variation is giving me false readings.
 

sandwarrior

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Re: HS Precision Throat Erosion

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mosquito</div><div class="ubbcode-body">Hello all, I have over 1,000 rounds in my HS Precision HTR in 308 and today I noticed with my Hornady Overall Length Gauge that the bullet appears to be .020 longer in order to engage the lands than when new. Throat erosion of .020 basically. It is only six months old and again 1,000 rounds shot through. I have ridden this thing hard in only six months but my question is, is this rate of erosion normal? It seems to be retaining its accuracy but will I need to ditch the barrel soon? Ive heard some say these 308 barrels can go for 10,000 rounds. I am beginning to doubt that. At least while retaining the 1/2 MOA accuracy it currently has. Thoughts?</div></div>

As noted there can be some variation in measurements. You have to use the same tool to measure each time. That includes the same bullet if you use it as part of the tool. Better to get an ogive comparator then you have the same tool each time for that. Also, while it may seem extreme that's only twice what Victor in TN uses as a comparison for a Bench gun. Bench guns have to hold a lot tighter accuracy than a tactical gun. Even though they still need to be very consistent.

I would take a look at WHY you think you are getting so much erosion. Powder, bullet, load pressure, and time between strings all come to mind. Can you think of a way to reduce it but still maintain adequate velocity? Are you hopping it up for too much velocity? I know a lot of guys who are very proud of the fact that they can get 2700 out of a 168, or 2650 with a 175 gr. bullet. The point is to make it consistent and if you have to back off then you'll extend barrel life. It may mean calling more wind and trajectory than you think you need to, but again barrel life is one of those consistency things to think about.

FWIW, I have a 30-06 with the throat eroded .250"+. It still shoots sub MOA @ 300. I'm not going to change the barrel or set it back until it won't shoot anymore. It's so eroded I can't seat a Berger 210 to the lands and have it in the case.