Blowing smoke?

[BradY]

My 260 improved F class gun has recently started blowing alot of blue smoke when shooting it. Its never done it before. Powder is the same lot H4350, primers I have moved to a different lot but tested them prior to this and had no issue. Cases and projectiles the same. Load is the same. The barrel is starting to foul fairly hard- carbon and copper. Have cleaned it up with iosso and JB bore brite in the throat to get it smooth again. The firecracking extends down a good ways in the barrel and its been left to carbon up a couple of times before. Just wondering if this smoke is a sign that the barrel is gone and needs to be replaced or if something else is amiss? Its also started throwing shots vertically too, when it used to hold a beautiful tight waterline to 1000yds. (Edited as Im sure it wont quite reach 10,000yds)

 

[jcampbellsmith]

.....it used to hold a beautiful tight waterline to 10000yds.

How big was you group at 5.68181818 miles? Regards JCS

 

[BradY]

Someone hacked me I swear : Fixed. I imagine it was in the low .2's.... of a mile that is.

 

[jcampbellsmith]

Someone hacked me I swear : Fixed. I imagine it was in the low .2's.... of a mile that is.

Time for another 260 barrel I think. I'm on my fifth 260 Rem barrel. Best regards JCS

 

[CaptainMal]

Oh you're all "hacked up".

Try soaking it in Bore Tech C-4 Carbon cleaner. Other than that it might be time to change tubes.

 

[bigedp51]

Question, are you shooting boat tail bullets? (I'm guessing that you are)

Try shooting some flat base bullets and see if it is still smoking, if it isn't smoking with flat base bullets then try some rebated boat tail bullets. The flat base and rebated boat tail bullets should expand and fill the bore and stop the blowing smoke. (blowby)

The British used rebated boat tail bullets in their machine guns and single base powders to extend barrel life and accuracy. These type bullets "obturate" when kicked in the seat of the pants when fired. (fill the bore)

Don't tell Boyd Allen I posted images of British .303 machine gun ammunition even though Lapua copied the British design. (for a good reason)
A standard boat tail bullet will not obturate (fill the bore) because the shape of the base prevents the bullet from expanding and sealing the bore. (blowby)

Sorry Mr. Boyd Allen but old milsurp rifles can have a lot of "blowby" and teach lessons in accuracy, even at AccurateShooter.com.

 

[smoking-brass]

How many rounds down the tube?

 

[BradY]

Yes 140gr berger VLD's for F Class. No good flat base bullets around Aus that will make 1000yds with the wind drift of these bullets....

About 1500 rounds down the tube. 1000 on the first chamber, 500 on the next.

 

[BoydAllen]

Have you looked past the throat with a bore scope? The reason that I ask is that a friend thought that he was handling a carbon problem by using IOSSO to clean his throat, but when we looked with a bore scope there was carbon for some distance past that, that he missed. If you have a similar issue, the restriction at the back of the barrel would cause a poor fit toward the front. When I use IOSSO (infrequently), I use a soft nylon brush, and sue progressively fewer short strokes as I work forward, and only concern myself with the back half to third of the barrel, depending on the number of shots, case capacity, and type of powder. From your description of the number of rounds on the barrel, it may be that for fine match accuracy, it is at the end of its life.

 

[Lapua40X]

Blue smoke in the exhaust often means badly worn piston rings or valve guides ;D
Sorry guys ---- just couldn't resist.

 

[bigedp51]

Blue smoke in the exhaust often means badly worn piston rings or valve guides ;D
Sorry guys ---- just couldn't resist.

I once put some habanero peppers in the cattle feed and it caused the cows to blow hot flaming smoke out of their exhaust.
We need to ask the OP if his barrel bellowed in pain and if it caused the other shooters to stampede.

 

[6MMsteve]

Interesting

 

[ShootDots]

My second .260A.I. was starting to give me low "X" counts at first(600 yard matches). Then It started shooting at the edge of the 10 ring. I scrubbed the dog out of it with JB and took it to my 'smith for a peer down the bore. Throat was eroded, but no more than what would have been seen with about 1000 rounds on it. However, the firecracking extended to about 6" down the bore. It was HEAVILY firecracked and looked like an 18th century cobblestone street. We started going over the matches I shot etc.. and I thought I had about 1600-1700 rounds on the bore. In reality I had over 2000! My guess with your barrel is, you simply need a new one!

 

[/VH]

My second .260A.I. was starting to give me low "X" counts at first(600 yard matches). Then It started shooting at the edge of the 10 ring. I scrubbed the dog out of it with JB and took it to my 'smith for a peer down the bore. Throat was eroded, but no more than what would have been seen with about 1000 rounds on it. However, the firecracking extended to about 6" down the bore. It was HEAVILY firecracked and looked like an 18th century cobblestone street. We started going over the matches I shot etc.. and I thought I had about 1600-1700 rounds on the bore. In reality I had over 2000! My guess with your barrel is, you simply need a new one!

Ben,
He was needing a new one three years ago.

 

[seymour fish]

My second .260A.I. was starting to give me low "X" counts at first(600 yard matches). Then It started shooting at the edge of the 10 ring. I scrubbed the dog out of it with JB and took it to my 'smith for a peer down the bore. Throat was eroded, but no more than what would have been seen with about 1000 rounds on it. However, the firecracking extended to about 6" down the bore. It was HEAVILY firecracked and looked like an 18th century cobblestone street. We started going over the matches I shot etc.. and I thought I had about 1600-1700 rounds on the bore. In reality I had over 2000! My guess with your barrel is, you simply need a new one!

Out of curiosity, what powder ? Approximate pressure ? Assume F-open, good pit service, and shooting as rapidly as possible when condition favorable, is this expected bbl life for the cartridge ?

 

[ShootDots]

My best

Out of curiosity, what powder ? Approximate pressure ? Assume F-open, good pit service, and shooting as rapidly as possible when condition favorable, is this expected bbl life for the cartridge ?

My best guess (each barrel will be different, sometimes significantly) is that you will get a solid 1700 rounds of accurate life..This will be with H4831SC and with the new RL-Powders, we will have to see! Pressures running about 63,000PSI.. In both my .260A.I.'s I am now running the RL-Powders, one with 16 and the other with 23..

 

[Zero333]

Excess oil (or cleaning solution) in the Chamber & barrel had one of my guns shooting blue smoke.

 

[seymour fish]

My best

My best guess (each barrel will be different, sometimes significantly) is that you will get a solid 1700 rounds of accurate life..This will be with H4831SC and with the new RL-Powders, we will have to see! Pressures running about 63,000PSI.. In both my .260A.I.'s I am now running the RL-Powders, one with 16 and the other with 23..

Benjamin, very helpful ! Thank you, sir

 

[GaryL1959]

My 260 improved F class gun has recently started blowing alot of blue smoke when shooting it. Its never done it before. Powder is the same lot H4350, primers I have moved to a different lot but tested them prior to this and had no issue. Cases and projectiles the same. Load is the same. The barrel is starting to foul fairly hard- carbon and copper. Have cleaned it up with iosso and JB bore brite in the throat to get it smooth again. The firecracking extends down a good ways in the barrel and its been left to carbon up a couple of times before. Just wondering if this smoke is a sign that the barrel is gone and needs to be replaced or if something else is amiss? Its also started throwing shots vertically too, when it used to hold a beautiful tight waterline to 1000yds. (Edited as Im sure it wont quite reach 10,000yds)

I shot beside a 308 a couple of weeks ago at a local match that blew so much smoke, I thought the guy was loading Pyrodex. Big cloud of blue smoke every shot...