Groups go to hell after 7 shots?

[thefitter]

Is there anything that can cause ones accuracy to go bad after just a few shots.

Totally clean barrel, 1st shot is always dead nuts on followed by 5-6 in one hole. Then it goes to hell.

Is the barrel fouling in some drastic way? Is it shot out? It's a stock .308 Rem 700 with 3000 rounds through it. I thought a .308 usually lasts 5000 rounds.

Thanks

 

[Samdweezel05]

I had a 6mmbr barrel that would shoot little ragged holes for the first 10 rounds of a clean barrel then go to crap. I got lucky and found a load the shot very well on a clean barrel and not so well on a slightly fouled barrel. I now do all my load testing on a barrel with 15-20 rounds through it first.

 

[fdshuster]

Most 308's have a record of approx. 4000 rds fired before moa accuracy becomes a problem, as verified in Kevin Thomas's testing of 4 308 barrels, in the Sept. 1998 issue of "Precision Shooting". You did not say what the barrel contour is. Sporter, Varmint or heavy Varmint? If it's a lightweight I'd be looking at barrel heat. If not that then I'd check the bedding, or rather, lack thereof. Most barrels do best when they are free-floated.

 

[thefitter]

Most 308's have a record of approx. 4000 rds fired before moa accuracy becomes a problem, as verified in Kevin Thomas's testing of 4 308 barrels, in the Sept. 1998 issue of "Precision Shooting". You did not say what the barrel contour is. Sporter, Varmint or heavy Varmint? If it's a lightweight I'd be looking at barrel heat. If not that then I'd check the bedding, or rather, lack thereof. Most barrels do best when they are free-floated.

It's described by Remington as "20” Heavy Barrel". It's in a Accuracy International Chassis System, so it is free floated.

Could it be some bizarre fouling issue? I always get a ton of copper out of it after even only 80 rounds?

Thanks

 

[dantiff2]

Only 80 rounds

I've found my remmy barrels are a PITA to clean with that many rounds through them. Is it possible your not getting it really cleaned? My 30 cal Remington barrel takes hours to clean after 50 rounds. I have a Shilen barrel that cleans up in minutes after 50 rounds.

Dan

 

[thefitter]

Only 80 rounds

I've found my remmy barrels are a PITA to clean with that many rounds through them. Is it possible your not getting it really cleaned? My 30 cal Remington barrel takes hours to clean after 50 rounds. I have a Shilen barrel that cleans up in minutes after 50 rounds.

Dan

Not sure I see what you are getting at. What difference would it make if I was not getting it clean? Do you mean that it's getting that much more fouled after just 7 more rounds?

I use Barnes CR10 and a bronze brush. Takes about an hour with all the soaking.

Whats your procedure?

Thanks

 

[bozo699]

Fitter,
I think your expecting to much out of a factory barrel.
If your getting 5 or 6 in one hole with a factory barrel I would be happy, if you took a bore scope I can almost guarantee you it would look like your sidewalk. depending on how it has been taken care of it could easily be shot out @ 3000 rounds. Unscrew that factory tube and put a good barrel on it and you will get what your looking for,.... top accuracy and easy to clean, JMHO
Wayne.

 

[RonAKA]

I use Barnes CR10 and a bronze brush. Takes about an hour with all the soaking.

Barnes CR-10 is a good copper cleaner. However, bronze contains copper. I would switch to a nylon brush with a cotton patch wrapped around it. You may be getting a false positive for copper using a bronze brush.

 

[thefitter]

Fitter,
I think your expecting to much out of a factory barrel.
If your getting 5 or 6 in one hole with a factory barrel I would be happy, if you took a bore scope I can almost guarantee you it would look like your sidewalk. depending on how it has been taken care of it could easily be shot out @ 3000 rounds. Unscrew that factory tube and put a good barrel on it and you will get what your looking for,.... top accuracy and easy to clean, JMHO
Wayne.

I get what you are saying but they question is - why only the first rounds of the day are accurate?

 

[whiskey08]

shoot 5 and clean, if the groups hold then its fouling or the barrel? If it doesnt, id look at the scope or mounts.

 

[LCazador]

You need a bore scope check , but bottom line is your barrel is shot out . I don't care who says what , you can't get more than 3K out of any barrel and that is only if you shot it very slow between shots . That bore is so gone that it only needs a few shots to foul , and foul badly it will . I have watched the progression of many barrels that were about to go , and when they are close they go fast . You can see bits and pieces of the bore fall out with every shot . As these bits and pieces fall out the jacket material that is removed on each shot becomes quite significant . You need a bore scope to see all this . Everything else is just a guess .

 

[Heavies]

My brother has a Remmy PSS in .308, and It will not shoot with a very clean barrel.

He is on a trip so I was working a new load for him with 155's. Now this gun is a genuine .5 MOA rifle. I have seen it time and time again from 100 to 600 yards. When I had it, it wouldnt group for beans. After consuting with my bro, I found I had cleaned the gun too much. I could tell that the barrel is very rough. Pushing patches down the bore feels like pushing patches through a rusty pipe. I have found that the gun likes to shoot fouled up.

My suggestion is, try fouling the barrel up with 10 shots, then rework the load a little, like how it had been suggested above. Then don't clean the barrel down to bare metal when you are done shooting. Just clean enough to get heavy carbon and copper out.

I am thinking that the copper fills in all the rough spots, and when you clean all of it out, the first rounds down the tube has to refill all the potholes. After all the potholes are filled pressure curves change, thus the need to tweak the load with the fouled barrel.

Id give this a try this before you dump the barrel.

 

[gambleone]

With a stock barrel & 3000 rds thru it,
sounds like after 5-7 shots the barrel is heating up & its
dropping accuracy. I agree with bozo699. New tube.

 

[fdshuster]

Wayne: After reading your post about the floated, heavier contour barrel, ( you did not describe the barrel contour in the original posting, so I thought it could have been one of the pencil thin contours/ great for carrying, not worth a damn for more than a few shots), and the other postings that followed, I'd have to agree to the suggestions: get rid of the barrel and replace it with a Krieger, Bartlein, Hart, or any other high quality premium, lapped barrel. If you do that, precision accuracy, and cleaning issues will be things of the past. If you've not already seen it, go to the barrels section on this site, and watch the Lilja borescope video of a new, unfired factory barrel. And, from a short article published in "Precision Shooting" magazine, Jan. 2000, page 63, and I'm quoting verbatum: " An executive with one of the largest rifle manufacturers in the United States recently remarked to a Precision Shooting writer that it costs them approximately $15.00 to make a rifle barrel".

 

[Larryh128]

Fire lapping will probably help some if re-barreling isn't an option at the moment for you. :

 

[mikecr]

I agree with Larry. Try a round of Tubbs FinalFinish(per directions).
I really think you're copper fouling out & FF often helps with this.

Another solver for copper fouling is bullet coating with Tungsten(WS2). You can dry burnish pre-foul with it to keep your excellent cold barrel POI performance.

Did you recently buy this gun, or did you shoot 3k rounds through it yourself?
If you shot it this much and just suddenly it's falling apart, then I agree with others that your barrel is likely broken inside(shot out). This can happen early with faster shot rates.

 

[artbosco]

It's a stock .308 Rem 700 with 3000 rounds through it. I thought a .308 usually lasts 5000 rounds.

Get yourself one of these barrels: http://www.kriegerbarrels.com/ and all your problems will go away. Most are good for 7000 rounds plus.

I read somewhere that the average factory barrel costs around $65 to manufacture, so in the long run you really do get what you pay for.

Go with a good custom barrel and your expectations will be exceeded. It's more fun when bullets keep going through the same hole.

 

[Ing. Michael W. Mayerl]

Is there anything that can cause ones accuracy to go bad after just a few shots.

Totally clean barrel, 1st shot is always dead nuts on followed by 5-6 in one hole. Then it goes to hell.

Is the barrel fouling in some drastic way? Is it shot out? It's a stock .308 Rem 700 with 3000 rounds through it. I thought a .308 usually lasts 5000 rounds.

Thanks

Clean it with KG12 and then polish with JB Bore Paste.
Which bullets do you use ? The old Barnes X without grooves show this problems.
Tip: HBN coating of the bullets gets more and more popular.

 

[ChuckMiller]

+1 LCazador, 3000+ rounds, factory tube = toast

 

[necchi]

Fire Lapping a shot out barrel ?
That would take bad an make it worse Cheesh ! :-\

I'm with Heavies on this one, leave'r dirty and re-work the load. That way you should be able to salvage at least some more shooting while waiting for another barrel.
Always tuff when ya hit the wall with an older barrel.