General observations

[AJC]

I am looking for general observations to increase my knowledge. Here are some I think I know but feel free to correct me or even explain...

1. Carbon ring occurs most often on overbore cartridges.

2. Cases with long necks help protect throats from burning out as fast.

3. Doughnuts happen most in brass with high shoulder angles that the brass does not flow and get trimmed off.

These are generalized statements that I am curious about from a troubleshooter perspective.

 

[Dusty Stevens]

I think all of your observations are wrong. Carbon rings can occur in a 223. Neck length has nothing to do with throat wear- dasher is a fine example. A 243 is a donut maker too- has more to do with die usage.

 

[BartsBullets]

Dusty Nailed it! ^^^

 

[garandman]

22rf has some pretty nasty carbon rings.

 

[mikecr]

All 3 of your notions really relate to shoulder angles and case dimension ratios.
An overbore cartridge burns enough powder for cal, as designed, to delve into diminished returns. A 243Win is a good example.
It has a low 20deg shoulder, high body taper, and relatively long for greater case capacity than needed with heaviest in cal bullets. Much of it's powder is funneled to follow the bullet (as additional mass) burning further down the bore and causing higher muzzle pressures. This leading to higher recoil, higher carbon fouling, lower barrel life, and virtually no chance of being competitive.
Pretty much everything about it can & has been improved over the years, with a myriad of .473 casehead, 24cal cartridges. Most are smaller, and improved 6BRs are best overall.

Regardless of capacity, Improving means holding up the powder for more burning of it in the chamber. This is done with low body taper, higher shoulder angle, and relatively large body diameter for length. A perfect example of this is 26wssm Imp, which is very efficient. A capacity reduced version of 24wssm Improved could be extremely efficient. With all powder burning inside the case.
High shoulder angles are also easier to manage. They don't need as much bumping, and so less brass is rolled into donuts(just opposite of your thinking). Less brass is also rolled from bodies into shoulders with lower body tapers.
And the mythical flame point design you're referring to is adjusted by shoulder angle. The higher the angle, the lower the flame point distance. I don't buy into the flame point theory, that longer necks are better,, just pointing this out.

 

[AJC]

All 3 of your notions really relate to shoulder angles and case dimension ratios.
An overbore cartridge burns enough powder for cal, as designed, to delve into diminished returns. A 243Win is a good example.
It has a low 20deg shoulder, high body taper, and relatively long for greater case capacity than needed with heaviest in cal bullets. Much of it's powder is funneled to follow the bullet (as additional mass) burning further down the bore and causing higher muzzle pressures. This leading to higher recoil, higher carbon fouling, lower barrel life, and virtually no chance of being competitive.
Pretty much everything about it can & has been improved over the years, with a myriad of .473 casehead, 24cal cartridges. Most are smaller, and improved 6BRs are best overall.

Regardless of capacity, Improving means holding up the powder for more burning of it in the chamber. This is done with low body taper, higher shoulder angle, and relatively large body diameter for length. A perfect example of this is 26wssm Imp, which is very efficient. A capacity reduced version of 24wssm Improved could be extremely efficient. With all powder burning inside the case.
High shoulder angles are also easier to manage. They don't need as much bumping, and so less brass is rolled into donuts(just opposite of your thinking). Less brass is also rolled from bodies into shoulders with lower body tapers.
And the mythical flame point design you're referring to is adjusted by shoulder angle. The higher the angle, the lower the flame point distance. I don't buy into the flame point theory, that longer necks are better,, just pointing this out.

Very helpful ****10**** thank you.

 

[ebb]

AJC I am kinda impressed. Most when replies don't go their way get in a huff. Keep listening, don't believe every thing, and soon you will know who is right all the time, who is right most of the time, who is right some of the time, and who is never right. I like listening to Dave Tooley, George Ulrich, Bart Sauter and Dusty. The only problem is they are out doing it not here talking about it much.

 

[ebb]

We used to have a guy in the last group, the one that never gets it right. I used to love to listen to him also. He had some theories!

 

[AJC]

AJC I am kinda impressed. Most when replies don't go their way get in a huff. Keep listening, don't believe every thing, and soon you will know who is right all the time, who is right most of the time, who is right some of the time, and who is never right. I like listening to Dave Tooley, George Ulrich, Bart Sauter and Dusty. The only problem is they are out doing it not here talking about it much.

I've been flame sprayed. Check my 357 loads in 38 case thread.... I am here to learn and don't claim to know much beyond the basics. I have been around machine tools all my life so feeds and speeds and nice tools is all I'm really able to bring to the table as strengths. I believe there is a big difference between your wrong and your a f***** idiot. One is a fact and the other is a feeling. Have all the patience in the world to be corrected, no time to be abused. Did I mention I love this site!!!!

 

[ebb]

Usually I get the "You are wrong, and you are a fux=/# idiot!" some times they are right. 38 loads in a 357 case that are marked well and you only own a 357 I could agree with. My mentor that taught me to reload, saw we were loading for a S&W model 28, told me use either of these 2 powders and pour the case full then seat a bullet. No other 357 in the house. There are 4 38 specials in the house so no 357 loads in a 38 case here. One of the women folk or me with too much shine and bad things can happen.

 

[AJC]

Are there books to learn about case design. Are the Ackley books something to check out.

 

[Tommie]

Neck length has nothing to do with throat wear-

Not arguing with ya but this statement is 180 degrees off from my experience. Worse case scenario would be short neck, shallow shoulder angle and extruded powder.

 

[Dusty Stevens]

I can sum up the ackley books- take any case, make it minimum taper, add a 40deg shoulder and chamber it to a crush fit on the go gage so your brass has a stop when forming.

 

[Dusty Stevens]

Not arguing with ya but this statement is 180 degrees off from my experience. Worse case scenario would be short neck, shallow shoulder angle and extruded powder.

Why do some powders not wear the throat near as fast in the same case? So ive found its flame front temp, bore/volume relationship, and cleaning interval (more shots between cleaning=more wear) and i suspect thats abrasive carbon build up sanding it out. F-class barrels dont last near as long as br barrels as far as cutting edge accuracy which doesnt matter as much in f class so its not even usually discussed. Take a dasher or a 6x47. Totally different necks and way off on bore/volume relationship. Put rl15 in each or rl16 and youll notice a difference. Then try varget. In the same case, same bullet youll notice way different wear in the throat

 

[Prose]

We used to have a guy in the last group, the one that never gets it right. I used to love to listen to him also. He had some theories!

Gosh I miss fguffey.

Does reloder 16 wear a barrel worse than h4350?

 

[Tommie]

Why do some powders not wear the throat near as fast in the same case? So ive found its flame front temp, bore/volume relationship, and cleaning interval (more shots between cleaning=more wear) and i suspect thats abrasive carbon build up sanding it out. F-class barrels dont last near as long as br barrels as far as cutting edge accuracy which doesnt matter as much in f class so its not even usually discussed. Take a dasher or a 6x47. Totally different necks and way off on bore/volume relationship. Put rl15 in each or rl16 and youll notice a difference. Then try varget. In the same case, same bullet youll notice way different wear in the throat

Like I said, not arguing. Your experience differs from mine. Fair enough.

Go Panthers!

 

[Alex Wheeler]

I have never had a carbon ring in any barrel. But I also have always brushed the bore and I do not go too long between cleanings. I feel that cleaning regiment is the answer to the carbon ring. A doughnut can form in any case for many reasons, but their problems are easily avoided. I do believe neck length plays a role in throat life. I think most of us that shot the dasher and switched to the BRA have seen much slower throat advancement.

 

[boltfluter]

I believe shoulder angle and neck length both play a part in throat erosion. Just makes sense to me.

Paul

 

[AJC]

I believe shoulder angle and neck length both play a part in throat erosion. Just makes sense to me.

Paul

It did to me as well but I was looking for general ideas and someone always provides the exception. My problem right now is completely understanding what the thumb rules are without getting lost in the battle.

 

[Forum Boss]

I shot a .260 Rem. Constant issues with doughnuts, even after I expanded from inside out then turned the neck-shoulder junction area. No doughnut issues with 6mmBR, and I'd say my 6 BRA is even less prone to doughnuts. But some of this has to do with case fit to chamber. My .260 Rem cases were fired in a rather generous factory chamber.