fire cracking

[rebs]

In a 223 cal is there any way to smooth out the fire cracking ? I have it in about the first 2 inches of my barrel

 

[GLShooter]

Nope. Not that I've ever seen.

 

[fkimble@charter.net]

JB it every 200-300 rounds and it will keep on shooting pretty good..

Frank

 

[rebs]

thank you
how many strokes of JB

 

[dcali]

JB won't do anything at all. The good news is that you really don't need to worry about it.

 

[K22]

How does the rifle shoot?

I had fire cracking in one of my 243 Win's, (Rem 700), and it still shot about 1 moa with tuned reloads. I would just keep shooting the rifle until it doesn't meet your standards.

 

[gunsandgunsmithing]

That little area where the neck ends gets beat on hard with lots of heat and an abrupt transition to bore diameter. I've got a new reamer that I'll try out soon where I laid that 45° angle down to 15°. It'll take time to know if it's worthwhile but I can imagine it helping bbl life a lot.

 

[Webster]

In a 223 cal is there any way to smooth out the fire cracking ? I have it in about the first 2 inches of my barrel

I had it real bad on my 6mm Rem. Keep shooting for many years as long as it shot under 1" at 100. For GH hunting. I don't know what smoothing would accomplish. Lets face it, time for a new barrel. I'm on my 2nd barrel on my 6mm Rem, 6mm Rem Douglas then a 6BR Norma Krieger.

 

[TRSR8]

Many CFBR guys, when a match barrel is getting long in the tooth with heat checking will use JB to smooth it out to help avoid coppering but at that stage you're coming to bbl’s end of life.

 

[jelenko]

JB to smooth it out

Just to clarify, smoothing out means smoothing the edges of the fire cracking, not removing the fire cracking so the surface is all smooth.

 

[gunsandgunsmithing]

Just to clarify, smoothing out means smoothing the edges of the fire cracking, not removing the fire cracking so the surface is all smooth.

Yes, I was thinking the same. Polishing it may take off the high spots but will do nothing for the bottom of the actual cracks in the metal. Once fire cracking starts, it propagates because the surface is roughened and just gets worse with time. Yes, polishing will help a little but my reamer design it intended to put off the start for as long as I can. First one so still yet to see how much difference it'll make.

 

[jelenko]

Yes, I was thinking the same. Polishing it may take off the high spots but will do nothing for the bottom of the actual cracks in the metal. Once fire cracking starts, it propagates because the surface is roughened and just gets worse with time. Yes, polishing will help a little but my reamer design it intended to put off the start for as long as I can. First one so still yet to see how much difference it'll make.

I go through ~ 10,000 223 rounds a season. If you had a way to make an AR barrel, I'd love to try out the design.

 

[gunsandgunsmithing]

I go through ~ 10,000 223 rounds a season. If you had a way to make an AR barrel, I'd love to try out the design.

My reamer is a 6 Grendel. I think the same has been done on other calibers though and I wanna say a 223 for ftr was one of them. You get a reamer and I can chamber it though. It'd be pretty tough to hit the number spot on but a 15° neck reamer may well work. I'd have to ponder it a bit.

 

[gunsandgunsmithing]

It'd have to transition from your neck diameter, to 15° and then to 1.5°. It's doable but a chamber reamer would be a lot the easiest, I think. I do really think it has potential to greatly help bbl life more than you'd think, though. If I could interest you in a 6 Grendel project, I would. I have nothing but good things to say about it.

 

[TRSR8]

It'd have to transition from your neck diameter, to 15° and then to 1.5°. It's doable but a chamber reamer would be a lot the easiest, I think. I do really think it has potential to greatly help bbl life more than you'd think, though. If I could interest you in a 6 Grendel project, I would. I have nothing but good things to say about it.

Most match barrels come to an end driven by combustion heat, cracking just after throat.
What exactly will a chamber design have to do with combustion related cracking?

 

[gunsandgunsmithing]

Most match barrels come to an end driven by combustion heat, cracking just after throat.
What exactly will a chamber design have to do with combustion related cracking?

I make no claims either way yet because it's just a "logical theory" at this point...at least to me. Here's a copy and paste from a thread on here about it...fwiw.


Well, it's cold out so I'm bouncing a couple of things that I've been considering for a while off of the vast knowledge base on here.
Right now I'm thinking about the area of the chamber between where the case ends and the throat begins. It's that 45° area at the end of the case mouth of the chamber.
Just thinking here and again, wondering if others have tried it or just what your thoughts on this are.

Any point like this that is fairly abrupt or has sharp angle changes becomes a heat sink area. We almost all have a borescope of some type these days and it's pretty clear that firecracking begins right there...and it makes sense that it would. Lets focus on this area for a minute. Exact neck diameter can affect the exact numbers but you'll get my thinking pretty fast, I think. In a pretty typical, say .272 6mm neck chamber, this 45° bevel is about .015 long..so it's short and abrupt, right?
I understand that very short freebores won't always work here but lets say we make that area 15° instead of the standard 45°. So, instead of it being about .015 long, it's now about .045 long, so you have to have at least that much freebore before you can even really consider this.

Bottom line, we've smoothed that heat sink down a lot. Will that help bbl life and will it affect accuracy in the short term? Logically, I see no reason accuracy should change either way but I see a very big potential for increasing useful barrel life.

Years ago, when Smith came out with their then new 500S&W revolver, they had pretty significant issues with flame cutting of the top strap portion of the frame. One of their engineers told me how they fixed it and it WORKED....they polished the inside of the top strap!! No rough edges to serve as a heat sink. The flame traveled smoothly over the smooth surface and didn't cut into rough areas, proliferating the whole issue as it grew and grew. I look at barrel break in pretty much the same way but that's a different subject.

So what are your thoughts. I think it has huge potential in regard to bbl life without any negative aspects as long as you have enough freebore in the given chamber design/bullet length etc. Maybe this should go in the gunsmithing forum but I'm mostly interested in competition gunsmith and shooters' opinions. Fire away. I think it's worth discussing unless someone that's done it can shoot it down. Thanks!--Mike

 

[searcher]

I haven't checked to see if they still sell them, but I believe they were made and sold by
David Tubbs if my memory is correct. He made abrasive coated bullets for smoothing the bore of crazy rough bores - but also had bullets intended to smooth the throat out. I once had a barrel where there was nothing to lose trying them out. They helped a lot, and for continued throat maintenance, shooting about four or five every few hundred rounds helped keep the sharpest edges down a bit. While I was wondering whether they might "finish off" the barrel, I was pleasantly surprised. Accuracy ever so slightly improved and the rifle was at least twice as easy to clean. I'd do them again if I wanted to get some extra miles for varmints out of a toasted barrel. If a match barrel for target shooting - I'd yank the barrel when it became unacceptable.

 

[rebs]

how much damage do you think is caused when you shoot 40 rounds through a 223 barrel one after another in one sitting and the barrel got really hot ?

 

[rijndael]

David Tubbs if my memory is correct. He made abrasive coated bullets for smoothing the bore of crazy rough bores

FinalFinish is the product name.

 

[cmillard]

I used some final finish once.....was a .452 kit for handgun. Worked perfectly. Bore wasn't lapped when I got the barrel. Grooves were rough looking, however the lands were nice and shiny/smooth. After running the kit through the barrel, night and day difference. Grooves looked great and was able to run more powder in my loads without seeing pressure (.460 rowland)