Barrel going south?

[eagleskier]

How do you tell if your barrel is burned out? My rifle is a 300 WSM and I have been shooting 175 SMK ahead of 65.4 grains of H4350. While I know that this cartridge burns up barrels fairly quickly, I have 731 rounds through it and it seems to be having trouble holding groups. I was able to hold 1/2 moa groups at 200 yards and now it seems hard to hold 1 moa.

I don't have a bore scope so that is out. The only thing that I have come up with is to start over on a load development and see if that helps.

Of course it could be me but like a lot of other sports it is never the indian, it's always the arrow.

Feel free to move this if it is not in the right place.

 

[SONIC SAAMI]

Re: Barrel going south?

Everything on the rifle is tight and the bore is clean?
If so then I would say the barrel is toast.

How fast do you push the 175s?

 

[eagleskier]

Re: Barrel going south?

They are moving at about 3050.

One thing that I did try was finding the lands by using a dowel. I still have the marks on the dowel from when the rifle was new. I put inserted a bullet touching the lands and put the dowel in. The best that I could tell, it was the same as when new.

 

[SONIC SAAMI]

Re: Barrel going south?

@731 rounds you have zero throat erosion?

 

[mtrmn]

Re: Barrel going south?

I know you're talking a WHOLE different ball game, but AR15 barrels would barely be broken in at 731 rds. It just strikes me as odd that a barrel would be shot out with less than a thousand rounds. But, that's probably why I'm no match shooter...

Surely you've checked all the obvious stuff-loose scope mounts, stock screws, etc etc. Maybe your shooting conditions or something have changed since load development? I would think when you go into re-development you'll find a load it likes again. Maybe get another known good shooter to throw a few groups out with it.

 

[bas402]

Re: Barrel going south?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: eagleskier</div><div class="ubbcode-body">They are moving at about 3050.

One thing that I did try was finding the lands by using a dowel. I still have the marks on the dowel from when the rifle was new. I put inserted a bullet touching the lands and put the dowel in. The best that I could tell, it was the same as when new. </div></div>

To tell you the truth you need to use a set of mic's to measure the throat, but since you didn't take the measurements with a mic when it was new... you will never know but I find it hard to believe that there is not ANY throat erosion. Heck throats will start the erosion process within the first 100 rounds and just keeps going though it will be very minimal but after that many rounds at that velosity... trust me you have throat erosion. Get yourself a mic and a Stoney point gauge and measure the throat and then set your bullets .020" off that measurement (ogive) as a starting point.
Sully

 

[eagleskier]

Re: Barrel going south?

Thanks, this is the kind of info that I am looking for. 731 rounds sounded too few to me as well. But I was looking for something to try from all you guys with much more experience with this than I have.

Any other suggestions?

 

[turbo54]

Re: Barrel going south?

Eagle, where in H'ville do you live? That's where I'm from! North end/Madison.

700ish rounds seems low for the barrel going away, but it happens.

I suggest you do a seating depth test.

Load several groups of 5. Keep your charge weight where it's at now.

Load 5 the same length you have been.

Load 5 .010" longer

Load 5 .020" longer

Load 5 .030" longer

If none of those group better, your throat is sad.

You could try the Tubb TMS, to smooth it out and hopefully get smore life, but a get a new barrel headed your way.

 

[milo 2.0]

Re: Barrel going south?

I don't think your barrel is toast, but there is some throat erosion. Try a new load is what I'd do, but would switch to a Berger hybrid bullet. They are not so sensitive to seating depth.
I had to do this in a 7mm saum, at 800rds, using a 175gr Berger, it went to crap. Switched to a 180 hybrid and ran another 1150rds through it. Then set it back 2 1/2", shoots better than ever, hope to get 3300rds total out of it.

 

[1lnbrdg]

Re: Barrel going south?

I always wonder about all the big hoop-a-la on the different throats for a cartridge. It might me a big deal for the 1st 500 rounds fired but after that, there is enough erosion that it doesn't matter, you don't have what you started with.

 

[Apex Motorsports]

Re: Barrel going south?

the first things I would do would be bore scope it, Check for loose scope mounts, over/under torque on scope/stock etc. Could have copper fouling if you haven't stripped the copper 300wsm will copper up faster than say 308. Also if you have a cheap scope (sometimes also with expensive scopes) you could have a broken erector etc. In my experience if known good ammo isn't shooting and I am not uber tired and shooting like a dumb ass it's usually things like scope mounts being loose that cause zero shift. So make sure you use thread lock on all the scope components and use quality mounts. Especially the hardware that holds the scope rails in place. Those usually come loose and no one suspects them.

 

[1lnbrdg]

Re: Barrel going south?

My 1st M1A barrel went south after 1200 rounds.

Short barrel life happens. The 300 Win Mag is a known barrel burner, just as a 6.5/284.

1K rounds and you are looking for a new barrel anyways. Play with it a little but with 700+ rounds on it, I'd start planning on a new barrel and I wouldn't waste a whole lot of time.

 

[eagleskier]

Re: Barrel going south?

Turbo54: southeast towards G'ville in Hampton Cove. Like most everyone else I am not "from" here. Been here since 1993 but always in Dixie.

What you are suggesting is basically what I plan to do. First thing is to start with a new OCW test centered around my present powder weight (65.4). Then go with different seating depths starting at about .020 off the lands.

As soon as I get a chance I will take it to my gunsmith for a look through the bore scope.

I also plan to swap out the scope with another one that should be better.

 

[X-fan]

Re: Barrel going south?

If the original load was developed via OCW you should just be able to let the bullet out and accuracy will return.

I was intentionally abusive to a factory Remington barreled 300Win (lots of rapid fire) and I got 1300 rounds before I got tired of cleaning it....Still shot well.
Another factory 300Ultra went south at 1100 rounds...Wasn't real kind to that one either.

730 rounds shouldn't kill a 300WSM...Unless you "cleaned it to death".

 

[Country]

Re: Barrel going south?

There is numerous things it could be. Start with a scope change to confirm the scope has not gone south .
Then check for bedding issues , stock warpage , oil in the bedding , garbage in the bedding , loose action screws .
Then try a projectile change just incase the ones that you are using now are not as intrinsicly accurate as the first ones you used which can happen.
If that does not change anything , then switch to a flat base bullet and if some lost accuracy suddenly returns then that can indicate that the barrel has suffered some wear.

 

[clmayfield]

Re: Barrel going south?

90% of accuracy issues can be traced to optic / mount. Insure that base screws, rail cross bolts and scope rings are all torqued to spec and try again. The recoil of a 300WM tends to jar things loose. I have had screws back out with my 308. Frustrating, but easily solved.

It is possible that the barrel is shot out in fewer than 1,000 rounds, but not likely.

 

[Drgonzo_1981]

Re: Barrel going south?

I can guarantee that it is throat erosion. Have read much on it and was really skeptical until I saw it for myself in a 7 rem mag that I had worked up a bughole load with 168gr bergers. I had to start changing seating depth after about 150 rounds! If you are running the loads hot., it is just the way it works! I would definitely get a mic for any rounds you reload, after having really gotten serious about shooting and seeing the difference it makes in my loads, I will have one for all my rifles!

 

[X-fan]

Re: Barrel going south?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WestTxMarine</div><div class="ubbcode-body">I can guarantee that it is throat erosion. Have read much on it and was really skeptical until I saw it for myself in a 7 rem mag that I had worked up a bughole load with 168gr bergers. I had to start changing seating depth after about 150 rounds! If you are running the loads hot., it is just the way it works! I would definitely get a mic for any rounds you reload, after having really gotten serious about shooting and seeing the difference it makes in my loads, I will have one for all my rifles! </div></div>
I agree.
Going from 1/2 MOA to 1 MOA at 200yds it seems like a minor tuning problem. At 700 rounds there is definitely throat erosion to be accounted for.

 

[ChadTRG42]

Re: Barrel going south?

Try a couple of things.

1- chase the rifling by seating the bullet out further and see if this helps restore.
2- rework the load by testing about .2 to .3 grains above and below your normal load and see what you get.
3- clean the rifle good. My comp rifles like no more than 130 to 150 rounds before accuracy falls off.

2 things happen when a barrel goes south. It looses speed and accuracy falls off. Chrono your loads and see what you have from when it was new. If the methods above do not work, you need a new tube.

 

[eagleskier]

Re: Barrel going south?

My next trip will include my chronometer to check the velocity. Thanks for the tip.

Could number of reloadings on the brass contribute?

 

[metal2meat]

Re: Barrel going south?

When I was in college I got my hands on a Winchester M70 22-250. I took it everywhere and shot the heck out of it. On a coyote hunt I missed three fairly easy shots. I stopped and shot a trashed refrigerator to check my rifle. At eighty yards I shot a 10" group!! I went home and checked all my screws, everything was tight. I had read that the 22-250 could be hard on barrel life so I quickly determined my barrel was toast. Took it to a smith and he could have took me for some bucks but instead asked if I had another scope to try. I changed scopes and sure enough, I was back under an inch!

Twenty years later, same gun, lots more rounds down the tube I started losing accuracy again. Granted I hadn't shot it as much as I did in the "early days", but I started thinking I'd finally burned the barrel out. I'm guessing I had approximately 800-1000 rounds through it. So I put it up for a while.

A friend turned me on to JB Bore paste a few years ago. On a whim I put some through the old 22-250, what could it hurt? Same loads I shot 20 years ago were back under an inch and closer to 0.5"!!! I always kept it clean and used copper solvents, but the copper that came out with the bore paste was amazing.

My opinion, try the cheaper simple fixes first. If they work- great. If not, at least you're not out much. Tighten screws, change scopes, check bedding and contacts, different cleaning and different loads/seating depths, whatever. It's great when you find a simple fix. Good luck

 

[eagleskier]

Re: Barrel going south?

My steps so far. First I have swapped the scope out and used the opportunity to check all ring and base screws. Second, I have annealed my brass. They had been shot 7 times without it. Third, I am redoing the OCW with 1 gr less to 0.5 gr above my normal load. Fourth, I will be checking velocities of the current loads with that of previous loads.

Anything else that I might try?

I'll post results as soon as I get back from the range.

 

[worldhunter]

Re: Barrel going south?

Copper fouling?