Carbon or firecracking?

[Dave in WI]

Is this carbon or firecracking?

 

[rijndael]

carbon OR firecracking? Maybe it's BOTH.

Clean it and find out.

 

[jelenko]

I'm betting it's carbon on top of fire cracking.

 

[Dave in WI]

6.5-284 with 5-600 rounds down it. Customer wants it shortened 3-4 inches and muzzle threaded. Was wondering if I should take off chamber end and rechamber.
What should I scrub it with?

 

[1911nut]

My Swift throat looked worse than that, terrible firecracking until I short stroked the throat with

on a tight patch. The firecracking was mostly carbon and the Iosso cleaned up most of it.

 

[ridgeway]

6.5-284 with 5-600 rounds down it. Customer wants it shortened 3-4 inches and muzzle threaded. Was wondering if I should take off chamber end and rechamber.
What should I scrub it with?

Get far ahead...your reamer will thank you.

 

[Dusty Stevens]

No way id ream that barrel with my reamer

 

[gunsandgunsmithing]

No way id ream that barrel with my reamer

I've done a bunch, never an issue. Carbon might be hard but it flakes off instantly and is typically way less than paper thin. HSS eats it out like it wasn't there at all.

 

[PigButtons]

I'm betting it's carbon on top of fire cracking.

I beg to differ, it is fire cracking under carbon.

 

[Ggmac]

ITS NEITHER, ITS TOAST !

 

[ridgeway]

It's not so much the carbon id worry about...I think it's more from heat treat it take when cooking rounds out of it.

 

[gunsandgunsmithing]

It's not so much the carbon id worry about...I think it's more from heat treat it take when cooking rounds out of it.

Scenario....Lets say we get a pretty phenomenal bbl life of 10,000 rounds and that the bullet spends nominally 1.5 milliseconds in bore with each shot. That's a grand total of 15 seconds of bbl life....err, time subjected to heat and pressure of combustion. I'm kinda doubting the heat treat changes in 15 seconds spread over a couple of years or more. Big maybe...but maybe at the edges of the lands or other very small heat sink areas.

 

[Dusty Stevens]

All i know is what the freebore area of my reamers look like on rechambered barrels and the way the next chambers look in that most important area- no matter how much i scrub them first. Whether its hardness or residual carbon (which is harder than HSS), doesnt matter to me.

 

[338 dude]

6.5-284 with 5-600 rounds down it. Customer wants it shortened 3-4 inches and muzzle threaded. Was wondering if I should take off chamber end and rechamber.
What should I scrub it with?

Set it back!!!

 

[Ledd Slinger]

Scenario....Lets say we get a pretty phenomenal bbl life of 10,000 rounds and that the bullet spends nominally 1.5 milliseconds in bore with each shot. That's a grand total of 15 seconds of bbl life....err, time subjected to heat and pressure of combustion. I'm kinda doubting the heat treat changes in 15 seconds spread over a couple of years or more. Big maybe...but maybe at the edges of the lands or other very small heat sink areas.

Well in that example 15 seconds would not technically the time of life that a barrel is exposed to high heat. Pressure sure, but the heat is compounded to a higher and higher temp on the steel with each sequential shot taken in a rapid string of fire. The barrel is exposed to high heat so long as a person is shooting and it is not given adequate time to cool down. Once the barrel temp reaches a certain point after “X” amount of rounds, then each shot thereafter without letting the barrel cool down is going to do more and more damage.

I laughed when I first saw Nosler release their 26 Nosler. I knew from the moment I read it in a magazine that it would be burning barrels so fast it be obsolete as fast as it gained enthusiasm. You never hear about anyone building a 26 Nosler anymore. That’s a ton of heat concentrated on a small .264” wide hole. All the big 6.5s are barrel burners. You shoot them sparingly to get around 700 rounds of barrel life or blast away knowing you will be replacing the barrel around 400 rounds. Just the nature of the beast.

 

[Dusty Stevens]

Well in that example 15 seconds would not technically the time of life that a barrel is exposed to high heat. Pressure sure, but the heat is compounded to a higher and higher temp on the steel with each sequential shot taken in a rapid string of fire. The barrel is exposed to high heat so long as a person is shooting and it is not given adequate time to cool down. Once the barrel temp reaches a certain point after “X” amount of rounds, then each shot thereafter without letting the barrel cool down is going to do more and more damage.

I laughed when I first saw Nosler release their 26 Nosler. I knew from the moment I read it in a magazine that it would be burning barrels so fast it be obsolete as fast as it gained enthusiasm. You never hear about anyone building a 26 Nosler anymore. That’s a ton of heat concentrated on a small .264” wide hole. All the big 6.5s are barrel burners. You shoot them sparingly to get around 700 rounds of barrel life or blast away knowing you will be replacing the barrel around 400 rounds. Just the nature of the beast.

A big 26 caliber magnum barrel life is more like 75rds

 

[LVLAaron]

All i know is what the freebore area of my reamers look like on rechambered barrels and the way the next chambers look in that most important area- no matter how much i scrub them first. Whether its hardness or residual carbon (which is harder than HSS), doesnt matter to me.

If anyone has a hardness tester I would be really interested in seeing what the throat area on a well used barrel measures at compared to the exterior muzzle end. Steel certainly work hardens...

Try and cut some train rail if you can get a piece. It's hard as glass.

 

[Ledd Slinger]

A big 26 caliber magnum barrel life is more like 75rds

yeah I don’t know what life would be on something really big like a 26 Nosler or 6.5-300 WBY because I’m wise enough from experience to know that’s WAY too much on a 6.5mm bore. Any 6.5 short magnum style round burning around 58-68gr of powder to push a 140gr bullet over 3200 fps such as the 6.5 Rem Mag, 6.5-300 wsm, or 6.5 SAUM, is gonna burn barrels pretty fast (400-700 rounds depending on shooting habits). Using a 6.5 much bigger than that like the ones based on the Nosler or WBY cases, I expect your throat would be in pretty bad shape after the initial 100 round break in period.

 

[rogina]

Set it back!!!

Borrow one of Dusty's reamers.LOL

 

[Dusty Stevens]

Borrow one of Dusty's reamers.LOL

Ill use his reamer on it!