Bullets, powder and barrel life

[Mr.Snerdly]

I have heard a light bullet is easier on barrels than a heavier bullet. This seems contrary to common sense but things are not always what they appear. I have also heard heavier bullets with less powder are easier so I don't know and I am sure there will be some disagreement but what do the majority say? I have also heard some powders are better for prolonging barrel life. What powders are best in this respect, for a 223, 22-250 and 243?

[Whynot]

Lots of theories out there- many that appear logical- but so many variables that it is difficult to prove. I think that bullet design plays a huge part in barrel wear, with flat base bullets being better. The problem with that is who wants to shoot a lower bc flat base at any real distance? Single base powders also appear to be kinder to barrels- but generally you get higher velocities with double base powders. So lots of boat tail bullets being pushed hard with double based powders = shorter barrel life. The double base each burn at a different rate so the pressure curve and flame temp last longer getting you more velocity. The trade off is temp stability and barrel life.

The 243 is well known as a barrel burner (most likely from the case neck design) and the 22-250 depends on how hard you run it- but it is overbore. But what good is a gun if you don't use it like you want and then deal with the problems as they come along....

But if I was to recommend a powder it would simply be a single base powder in the appropriate burn rate.

[Dave Hoback]

It’s proven that bullet speed, pressure & overbore are the factors known for barrel wear. As for bullets. Maybe to some degree. But it’s not discernible against say, overbore. As for powders. Once again, maybe. Although I believe it’s all in the powder’s burn rate, which in turn yields different pressure levels. So again, it’s “Pressure”, not the powder itself.

[CFJunkie]

Normally, lighter bullets attain their higher velocities with less chamber pressure.
That might be the reason for someone to make the claim that light bullets are easier on barrels.

I would say that a light and a heavy bullet firing with the same chamber pressure would have about the same impact on barrel wear, as well as on the brass.
The lighter bullet would achieve a higher velocity but that doesn't mean that the wear would be any worse.

[charlie b]

Has to do mainly with the volume of the burning powder. Cartridges that are called 'over bore' are shoving a bunch of burning powder down the bore. Krieger refers to this as a plasma but I am not sure it fits the classical definition. The burning particles are really bad on the barrel. You can see the effect with a borescope in the barrel near the throat, which is why you can sometimes 'refresh' a barrel by cutting off a bit of the chamber end and using a reamer to get to 'good' metal.

If you see more 'efficient' cartridges they will have smaller charges of powder. The BR and PPC family are good examples of this. They don't lose that much in velocity and do so with a fraction of the powder charge, which means much less 'plasma' in the bore. Some claim that the shoulder angle makes a difference as well. Not sure if it is true or not, but, I could probably be convinced of it if someone had some true scientific measurements (not just hearsay, or, this one worked and this one didn't).

SWAG follows: Heavier bullets mean the 'plasma' may burn out before the bullet travels as far in the barrel (and has lower particle velocity). Light, high velocity bullets mean the 'plasma' travels through more of the barrel at a higher velocity.

[Dave Hoback]

Plasma? In a firearm’s cartridge gases? No. Although Plasma has different forms & heat(like Neon which is room temp), we most normally associate it with extreme heat. And in this, it’s certainly the case. Gas is converted to Plasma around 6000 Kelvin. The combustion temps reach a maximum of maybe 3400F, which is something like 2100 Kelvin or so. Not even close to Plasma.

[charlie b]

That's why I questioned it. But, 'plasma' is used in a lot of cases where it is technically not correct. Most people view it as a very hot flame, like plasma cutting, and don't concern themselves with the details. "Flame cutting" is not dramatic enough I guess.

[Dave Hoback]

Lol. I guess it’s better than referring to it as “An Explosion”!, huh? :surprise:

[charlie b]

Well, it could be called an explosion, just not a detonation :)

[GrenGuy]

Mr.Snerdly, IMO, if one is concerned about barrel life, one should shoot a 30 caliber. Shoot a 308 Win or a 30/06, and try to wear it out in one lifetime. Shoot any compatible powder, any compatible bullet, abuse it, don’t clean it, and please let us know when it falls below acceptable accuracy. It’s a simple equation, the smaller the bore, the more powder, the number of shots fired per period of time, will determine the life of a barrel for acceptable accuracy. If I shoot one 6BR in Light Gun and Heavy Gun, in 600yds, and 1,000yds, I would be hard pressed to make that barrel last “ONE SEASON”. When we buy powder in 1 pound containers, it is some what a non issue. People who have to consider barrel life seriously, buy powder in multiple 8 pound containers. Fred once told us, on the average, a barrel is good for 12 pounds of powder. Until I got into what I’m doing now, I never thought that could happen. But now, powder is a major consumable, and so are barrels.

To perhaps be more practical, let’s say I find the most gentle powder and the most gentle bullet, but the best I can do is a 3” group at 100 yards. But I’m saving My barrel. I have never encountered any one on this site that would find that level of accuracy acceptable.

I have 1 pound of RL 17, which is known to produce impressive velocities. But it is also claimed to be a “throat burner”. At some point soon, I will have to shoot that powder, because I can’t get the powder I want, “if I want to continue shooting”. Sorry about that “throat”. IMO, the bigger issue is how, when, if, ... am I, You, We, going to be able to get the powder and bullets we want??

I could go on about the shortages, but its time to close this book. Hope I may have made a point “Snerd” ��

[Dave Hoback]

I like RL17. That’s my go to for my 260.

[Mr.Snerdly]

Would a 223 last about as long as the 30 calibers? I was looking at the 223 compared to the 30-06 and both work pretty well with CFE 223 with certain weights. The 30-06 takes roughly twice the powder but the area of the bore is less than twice the 223. There may be other things I am not thinking about but I bet they would have close to the same life. A 308 takes a little less powder but still about twice the 223.

[GrenGuy]

They call it “over bore”. I always thought it should be “under bore”. Then I decided they were talking about the chamber being over bore in relation to the barrel bore? Whatever? The 223 has a small barrel bore, but also a small chamber bore, providing a good balance. I have never known the 223 to be a barrel burner? I would think You’d be hard pressed to shoot one out.

[Txhillbilly]

Most 223's will get 2-3 times the barrel life over a 308. Depending on several different factors involved, a 223 barrel can get 12k - 15k rounds out of it.

[wbm]

https://www.accurateshooter.com/technical-articles/overbore-cartridges-defined-by-formula/

[GrenGuy]

Let’s see, 223 Rem, 55grn bullet, 25grn load of Varget

7,000 grains of Varget (1#), divided by 25grns per load, =280 loads per# of powder, divided into 15,000 rounds fired, = 53.57 pounds of Varget.

Woah! Did I get that right? That is some serious “underbore”!

I have a 6BR barrel with 2,200 rounds on it that is loosing match accuracy fast. That is 7,000grns of H4895 (1#), divided by 30grns of powder per load, = 233 loads per #, divided into 2,200 rounds shot, = 9.44 pounds of powder shot. Yep, that’s just about right on. That is a hot load, but it what that barrel likes for accuracy. Short life, but it’s the price I have to pay to try to put em in the x ring.

I might get Me one of those 223’s, if I thought for sure I could get Ammo. Oh, I just remembered, I have one in a TC Contender. Too many barrels to keep track of. Keep em small !

[Dave Hoback]

I like 223. However, I like it for the rifle it was designed for. My last built AR uses a Stainless 1:8, Wylde, Nitride QPQ barrel. It shoots inside 1 MOA and will continue to do so for about the next 30,000 rounds or so! In other words, more than I’ll ever shooting, HA!

[charlie b]

I like my .223 Axis a lot. It was so accurate and easy to load for it got me into another Savage in .308 (mainly for cast bullets). The only downside to the .223 for me is at distance. The 77gn bullet my 1-9 twist will handle is on the ragged edge for accuracy at 600yd (23.5gn Varget, Lapua cases). Takes good skill with windage to get reliable hits (I am not that skilled :) ). The 80gn might be a little better (1-7 twist?) but is still a bit light. Quite a few FTR folks seem to like it for the 600yd targets.

I did shoot a couple groups with mine at 1000yd, just to see what it would do. 15" and 18". Not to shabby, but, not anywhere near competitive.

FWIW, I now have a 6BR barrel. Not really going to push velocities on it, but I already like the heavier bullets. And a LOT less recoil than the .308 and 155gn bullets. Saves on powder too :)

[Whynot]

Found an old article about barrel life in an old magazine (cant find it online to post a link)- and it had some interesting things in it. They down loaded a 22-250 to a 222 pressure and velocity and tested barrel life on multiple barrels. The 22-250 still burned barrels faster even though they had the same pressure. They also listed boat tail bullets as being worse for barrel life because unlike a flat base it does not "bump up" and seal the bore but instead funnels expanding gases to the throat- focusing them more on the barrel.

As far as powders... double based powders have more energy per grain than a single base- they can achieve greater velocity with the same pressure because they have one quick burning base and one that is slightly slower- so the peak pressure does not rise but the time that the bullet is under max pressure does. With a single base the temperature and pressure are reduced quicker- and that is why the double base powder is harder on barrels. If you downloaded with a double base to the same velocity as a single then it would do this with less pressure (but still a longer burn time) and may not be as hard on a barrel. But the reason to use a double base is to get higher velocity and if you are not going for that you may as well use a more temp stable single base.

But if you have enough patience to let a barrel cool between strings then most of these things are not a huge issue.