What to look for when a rifle will no longer group.

[Someoldguy]

I guess I should not say anything but guys are getting into this type of shooting where they are shooting 10 , 20, 25 shot groups and want to use a High speed, High performance cartridge. Barrels will not last...Get a HB 308 Win. and now you know why.

A good 308 barrel can last 5K rounds or 2,500 shooting non stop 20 round groups

Oh, well now you're just being practical.

 

[tmwinds]

I have a custom 6BRX that would consistently shoot 1/3 moa at 525 yards. I bought a Lyman bore scope on sale from Brownells. Took a look at the barrel and saw it looked like a dried up river bed for about 6 inches. Now I can barely hit the target backer. The moral of the story is, if it's shooting don't use a bore scope.

 

[Steve Ladino]

Well I hope that is not the case because I ordered a jar of it today with new brushes including the new Hoppes "tornado" brush to try and give it a good cleaning. Something has to be done as I have gone through every screw and checked everything I know to check. I'm ruling out the scope as it less than two months old and shoots perfect on my 6.5 Creedmoor (tried it yesterday) I put the scope back on the .243 and went to the range again tonight and got so mad I came home early. Best group at 200 yds was 5.4 inches with 5 shots! Tried Hornady 75gr Vmax and Nosler 80gr ballistic tips and sometimes you get two touching and the rest looks like a slingshot sent them. If a good cleaning don't restore the accuracy then the gun is gone.

I believe that if you have cleaned your barrel with any amount of effort you should notice quite a difference on target if fouling was a problem.

 

[Milo 2.0]

If it was me and a factory barrel, I wouldn't mess with it, just rebarrel it. I had one 7 saum that had 1 1/2" of rifling gone, and still shot 5" at 1600 yards, 3 shots. I've also had a premium barrel in 6 comp match that dumped pressure at 800 rds, and was done at 1200, with .028" of throat erosion.
Life is too short to bring a horse back from dead.

 

[Lefty Trigger]

If it was me and a factory barrel, I wouldn't mess with it, just rebarrel it. I had one 7 saum that had 1 1/2" of rifling gone, and still shot 5" at 1600 yards, 3 shots. I've also had a premium barrel in 6 comp match that dumped pressure at 800 rds, and was done at 1200, with .028" of throat erosion.
Life is too short to bring a horse back from dead.

I agree and that's why I sold the gun, bought a Savage 12BVSS in 308 and love it! Minor problem with the stock but Savage is quickly replacing it. Bought new gun for just about $250 more than what rebarreling the .243 would have cost me.

 

[Milo 2.0]

I agree and that's why I sold the gun, bought a Savage 12BVSS in 308 and love it! Minor problem with the stock but Savage is quickly replacing it. Bought new gun for just about $250 more than what rebarreling the .243 would have cost me.

I have 400 rds on proof carbon barrel 6 dasher, every time I fire it I seem to lose speed. I'm going to clean it today, hoping carbon fouling near the muzzle is causing drag, if that's not it, not sure what I will do, lol

 

[coldboreshot]

Lefty,
Have you been following the erosion of the lands as you have been seating your bullets since day one? Check the throat erosion depth then run up some rounds the same as where you left off and reset (if necessary) the bullet seating depth whether you jam or jump the bullets. Even jumping bullets, eventually you will reach a distance that the bullet just does not like. If you have been seating at the same depth, it may be time to evaluate, given the 650 round count. And I agree with previous comments; watch your powder lot and primer lot changes. Annealing is not always the cure-all. I have associates who have 20-25 loadings on their brass and never annealed once and their loads perform flawlessly.

I think one thing many overlooked (I don't know, there was a lot of reading here) was the possibility that you might have a nick on your muzzle crown which could send your group size south out of nowhere if you don't know it's there.

I have seen a rifle at a match shoot great then all of a sudden, the accuracy just dropped completely. Turned out, the erosion just reached that one small spot where the bullet did not like. The shooter never followed the erosion and corrected the seating depth.

It's not always in the cleaning.

 

[Lefty Trigger]

Lefty,
Have you been following the erosion of the lands as you have been seating your bullets since day one? Check the throat erosion depth then run up some rounds the same as where you left off and reset (if necessary) the bullet seating depth whether you jam or jump the bullets. Even jumping bullets, eventually you will reach a distance that the bullet just does not like. If you have been seating at the same depth, it may be time to evaluate, given the 650 round count. And I agree with previous comments; watch your powder lot and primer lot changes. Annealing is not always the cure-all. I have associates who have 20-25 loadings on their brass and never annealed once and their loads perform flawlessly.

I think one thing many overlooked (I don't know, there was a lot of reading here) was the possibility that you might have a nick on your muzzle crown which could send your group size south out of nowhere if you don't know it's there.

I have seen a rifle at a match shoot great then all of a sudden, the accuracy just dropped completely. Turned out, the erosion just reached that one small spot where the bullet did not like. The shooter never followed the erosion and corrected the seating depth.

It's not always in the cleaning.

Yes I kept records on that from the lands depth on various bullets measured when new. Very minimal erosion .0005-.0007 best I could measure but still less than .001. That's why it was so frustrating that it quit grouping, couldn't really find a reason??

 

[coldboreshot]

Roger that. Run a nice sized magnifying glass or even the borescope over the muzzle and check for nicks or other abnormalities.

 

[coldboreshot]

Sorry, muzzle crown

 

[coldboreshot]

Some would disagree but the crown can be damaged just from the contact of the cleaning rod jag, over time. It''s a finely cut edge.

 

[dcali]

Remember that a lot of black using JB's is very fine metal from your barrel.

This took me an embarrassingly long time to figure out. Taking a clean patch of JB and rubbing it on the *outside* of the barrel is very illustrative. I don't know why, but it turns black almost instantly.

 

[Clancy]

I just read this very interesting thread word for word. I have a few comments....

I want one of these barrels that cleans with only 2 patches

JB should be in everyone’s cleaning kit, and used every 250 rounds or so, when the rifle won’t shoot from a regular cleaning.

Please don’t rebarrel a fine rifle to 7mm-08/308. There’s so many better choices, most of them ending in “X47 Lapua.”

 

[FrankG]

To recap some of the things mentioned....

I'd have the muzzles crown checked. The crown will wear just from the gas cutting effect from the powder not to mention cleaning damage.

Factory button rifled barrel? I'd say it's toast. Maybe/sometimes you can get more out of it but my guess with out looking at it.....I'll say toast.

Talk to the ammunition makers/testers. Where they have to hold pressure and velocity with Saami spec. ammo...they are usually throwing the barrels away slightly before a 1k rounds in .243win. The .243win. is hard on barrels. Accuracy wise it could still possibly perform but usually just under 1k and you have to maintain pressures and velocities....the barrel is on it's last legs no matter what by a 1k rounds.

When we do testing here guess what we chamber the barrel in? You got it .243win. I can shoot X amount of rounds in a short range session vs. a .300wm and I don't have to take a pounding. The .243 is as hard or harder on the barrel than a .300wm.

JB Bore Compound I'm o.k. with but not the other paste/abrasive type cleaners. Also a big no no using an abrasive and a brush in the bore of the barrel. I'll guarantee bore damage will result. It's just a matter of time. I've barrels show damage with only a 100 rounds on it. It wasn't from shooting but from the shooter using a bore past and a brush. How the guy cleans it and how aggressive...no one can control and one guy doesn't differently than another guy.

Later, Frank
Bartlein Barrels

 

[Lefty Trigger]

Please see post #45 above. This is a dead thread now as I have since sold the gun. Replacing the barrel on a Winchester M70 control feed is a huge deal that only talented smiths can get done properly having to cut that extractor groove in the barrel.

 

[FrankG]

Please see post #45 above. This is a dead thread now as I have since sold the gun. Replacing the barrel on a Winchester M70 control feed is a huge deal that only talented smiths can get done properly having to cut that extractor groove in the barrel.

Yes I seen that you sold the gun as well.

Installing a control round feed Model 70 is no big deal. We do extractor type cut barrels all the time on Model 70’s, 1917 Enfields, 1903 Springfield’s etc...

Later, Frank

 

[6MMsteve]

hope your new barrel shoots great

 

[coldboreshot]

Never consider threads like these "dead". This is always useful information to others who may not have been involved from the beginning but may have future issues to use as a reference.

 

[bill2]

My .243 has about 650 rounds down the barrel and would give really good results with many different bullets and/or powders. However lately it has gone all wonky at any range above 100yds. My go to load is 87gr Vmax with H100V powder at 39.6grs and will group dime size hole at 100yds. and just over 1 inch at 200yds and under 2 inches at 300. Yesterday and today as well best I could get at 200yds was a 4.5 inch group! I have noticed that this has been getting worse for about the last month or so and have cleaned the barrel with several cleaners and copper removers with no improvement. Could the barrel be getting at the end of it life span? Oh, Winchester M70 stainless light barrel 24 inch.

Bore scope saves much time and expense.

 

[stifffingers]

For a gun that goes Wacko, that is properly bedded, you have checked all screws, magazine box is not in a bind, & changed scopes:

1. Check seating depth
2. powder fouled
3. brass has super work hardened necks-anneal*********
4. you changed to another lot # of powder
5. Change to another brand of bullet, the lot # of bullet you are shooting
is not as good as the previous lot that was shooting good.

It has been my experience in helping guys that only clean when there is an accuracy loss do not have proper cleaning equipment(they do not like to clean). This may not be the case with you, but it leads to some super hard carbon issues as the carbon is super cooked. If there has been carbon/copper build up to a point of loosing accuracy, then you need a very aggressive cleaning regiment to get fouling out to bare metal. If you do not clean down to bare metal, the carbon that is left in the barrel will get super heated to the point to where it may not come(extreme case) out with anything less than 0000 steel wool wrapped in a brush with JB, IoSSO, or Flitz in the steel wool.

For many years we always shot our barrels to where they were super fouled on large pristine Prairie dog towns, but we did learn hard lessons in cleaning filthy barrels. Our normal regiment was 300 rounds on 223's, 22 & 6PPC, and 150 rounds on 243 AI's. We were shooting 600-1100 center fires a day.

Please throw those tornado brushes away!

Buy Good bronze bristle brushes by the dozen as a good brush is only good for around 100 strokes. After 100 strokes you are not scrubbing the groove, only the lands:
https://www.brownells.com/gun-clean...ozen-pack-bronze-rifle-brushes-prod40081.aspx

For anyone that is a gun enthusiast, the Lyman bore scope is a truly one of the best tools you can invest money in. Buy one and you will NEVER regret it, and you will become your own expert. The bore scope will remove all doubts when it is time to re barrel.

Often, shooting buddies/family members will go in halves on a bore scope:
https://www.brownells.com/gunsmith-...opes/borecam-digital-borescope-prod81507.aspx

Good luck

Can not agree with the mention of using 0000 steel wool and JB or Iosso to clean a terribly fouled barrel. That would be a job for Bronze wool, available at all woodworking supply stores.