I stumbled across a chart in the medium bore forum that lists popular powders vs. number of shots to expect before you burn up your barrel.I had never given the powder choice a second thought as to barrel life as I had assumed(a mistake on my part?)that a given cartridge had X number of shots before it was "shot out",regardless of powder used,though the powder charge will affect barrel life.
Example 1:In a .27-.30 caliber using 4350.(It doesn't say which 4350.)You can expect 3,000 rds. before the barrel is "shot out".But using 3031(chart does not specify IMR or other,just 3031)barrel life jumps to 5,250.There aren't any charges listed,only type of powders.
Example 2:In a .20-.23 cal. w/4350,the chart lists # of shots at 1500,w/3031 it soars to 4,000.
Does slower powder make that much difference in the life of a barrel,and if so,why?This is a whole new world of handloading that I had never neard of.Enlighten me please.I'd like my guns to last as long as possible.

Slower powders are used in larger cases.

Larger cases produce more velocity and longer flashes and as a result the barrel is eroded faster.

I doubt the chart is as it implies. It implies that slower powders erode more and it's true but not because they are slower. We just burn more of it every time we shoot.

I've read that the amount of powder burned - the charge weight - has a bearing on bore life. All else being equal (rarely the case), lighter charge weights of a particular powder cause less bore wear than heavier charge weights of the same powder.

Your example from the table seems consistent with this. 3031 being a faster powder than 4350 would be loaded in lighter charge weights than 4350.

There's been quite a debate about this among target shooters (who wear out barrels as a matter of course), seemingly without any real consensus.

The respective sides argue that slower powders often operate with lower overall pressures or with pressure curves that are kinder to the barrel's throat. The fast-powder advocates invoke the charge weight theories and lesser amounts of heat generated.

Who's right is anyone's guess. I load fast powders at low pressures, since speed earns you little in most paper games. I can't take one side over the other.

Mark

I would think, without any real study to back up my thought, that the following would affect barrel life:

1. The temperature of the gas going down the barrel. Some powders burn hotter than others.

2. The abrasiveness of the particular powder and its residue.

3. The amount of powder burned.

4. The velocity of the gas which obviously won't be faster than the bullet velocity.

I think it's a combination of how hot and how long the powder burns. Large charges of slow powders produce long burn times which increases the heat inside the barrel. An example, a 257 Weatherby vs. a 22Hornet.

I will throw another wrench into the works. I wish I could remember the link, but it was a throat erosion study doen in Australia and it stated that ball powders caused much higher throat erosion due to the abrasive qualities of the yet unburnt powder pounding the throat. Wow that is a long sentence!

Double base burns hotter (due to the increased energy) and increases wear.

I've got a 6.5x55 whose throat is the living proof that 2kg of N5 series shot at reasonable pressure can do serious damage. If I'm honest the cleaning regime used a pretty pathetic copper solvent (an old Parker Hale solvent) but even so.......

Right - this is not a statement of fact (or belief) but a simple speculation! Slower powders have more bulk and because they burn slower, will be pushed down the throat as they ignite, releasing huge amounts of oxygen and heat as they pass over the steel surface of the bore. How much surface oxidation or 'flame cutting' takes place with each shot? One thousand five hundred shots begins to sound like a good lifespan! Just a thought.

Here it is again

SOmething to keep in mind though. When they say "burned out" It doesn't meant the entire bbl. but the throat. This can have a negative affect on accuracy or not. For a traget shooter or varminter, maybe it's a big deal. For a big game rifle, probably not. Also throat errosion has a lot to do with how hot you get the bbl. Shoot a semiauto 1 round per second, it's going to cause more throat errosion than 1 shot per minute.

I started this thread 'cause I started shooting steel silhouette/hunter class.This year there are 8 matches.Each match will be 80 rd. shoots,plus sight-ins.That means I could shoot at least 800 rds. this year in competi-tion,plus whatever I shoot practicing.We are allowed to use different guns for the different ranges if we choose,which I will do.Not to save on barrel wear,just to save my shoulder.80 rds. through a Rem. 700 30-06 in one day is doable for me,but I'll use the 22-250 for 200-400 meter targets.
Woods, thank you for posting that barrel- life chart.That's the one I was refering to.

Here is my one experience with shooting out a barrel.
Springfield M1-A, 308 Win, LC brass, Sierra 168 Matchkings, over 41.5 gr IMR 4895.
Just shy of 6000 rounds down the pipe when it was replaced. It quit shooting better than I could.
Fired in NRA high power/service rifle competition. That is 88 rounds 8 sighter, 80 for score. 40 slow fire 1 minute per. 40 rapid fire in 10 shot strings at 2 to 3 seconds per.
My 2 cents worth.

muck

Well what it clearly shows to me is that the bigger the caliber the slower the powder you can use and get more barrel life. For instance if you use H1000 in a 257 Weatherby the chart says 1,000 rounds but if you use it in a 338 RUM then the chart say 2,250 rounds.

That clearly defines why the overbore calibers like the 264 win mag or 257 Weatherby have such low round count barrel life because they thrive on the slower powders like H1000, RL25 or even the old H870 (500 round count for a 264 win mag).

Makes me wish my 6.5 rem mag didn't like RL25 so much!

Woods,I agree that a bigger bore will have a longer barrel life than a smaller bore,however,if we compare one caliber,say a .22-250,and compare barrel life to a given powder,there is a good bit of difference in the life of the barrel.
Let's use 3031 and 4350 as our examples.According to the chart you posted, 4350 will get you approx.1500 shots,while 3031 will get to 4000 rds.before the same gun is shot out.
I am all for as accurate a gun as I can load for,but I would give up a little MOA to significantly increase the life of my barrel.
I'm not trying to get into an arguement here,only to get a better understanding of what I can do to get descent MOA and extend the life of my barrel.

I completely agree. However, generally speaking, the slower the powder and the more you fill up the case the better the velocity and accuracy, IME.

Life's a compromise.

I follow the 'less powder in the case, the less the barrel wear per shot' crowd...

Fast powder in a 223, I traded off a Ruger that had 15,000 rounds down the barrel...

the guy who bought it, from where I traded it in, had shot another 2,000 rounds down the barrel when I met him at the range one day...

so after 17,000 rounds down the barrel, it was still shooting groups you could cover with a nickel at 100 yds..

quote:

so after 17,000 rounds down the barrel, it was still shooting groups you could cover with a nickel at 100 yds..

Holy Cow!

Just one question... How does one count the number of shots fired? I don't keep my primer boxes nor my bullet boxes and I don't shoot regularly nor consistantly, so I cannot estimate.

P.S. I saw a framed print of your Spitfire picture in a TV show last night!

Don't giveall the blame to the burn rate some erosion is the fault of us shooters as we fire groups too rapidly w/o letting the barrel cool between shots makes the steel more suscepible to damage.

The way I do a "too hot to shoot" barrel check is to grab the barrel with my bare hand.If I can't hold it firmly for more than 3 seconds,it won't get shot again until I can.I forget where I heard/read this,(probably on this website sometime ago)Seems to me like a descent way to not get your barrel too hot.I've using this method for a few years now.The point is I don't think I get my barrels too hot.Remember,I am trying to understand why slower powders will, theoreticly,cause faster barrel wear.What several posters have said about the slower powder burnlng farther down the bore,hence causing more(faster?)wear seems reasonable.Lately I have been using IMR 4350 in 4 of the centerfires that I load,but,after reading these replys,I am going to give a faster powder a try.I'll start with IMR3031 as that is what I have on hand.Thank you all for your comments.They really made me think,in a different way,of what causes a barrel to wear and what I can do to get more life out of them.
Never gave the burn rate a thought as to wear, but it will become another variable on my loading bench,as long as MOA is acceptable.
Again, thank you Woods, for posting that chart on the medium bore forum.With the information on that chart,maybe I can get alot more life from my guns.

quote:

Originally posted by prplbkrr:
Remember,I am trying to understand why slower powders will, theoreticly,cause faster barrel wear.

I always thought it was like the difference in pouring a couple of drops of gasoline or a couple of drops of diesel on a steel plate, lighting them and seeing which gets the plate hotter. The gasoline will be gone a lot quicker and the diesel will burn longer and get the steel hotter.

quote:

Originally posted by 303Guy:

quote:

so after 17,000 rounds down the barrel, it was still shooting groups you could cover with a nickel at 100 yds..

Holy Cow!

Just one question... How does one count the number of shots fired? I don't keep my primer boxes nor my bullet boxes and I don't shoot regularly nor consistantly, so I cannot estimate.

P.S. I saw a framed print of your Spitfire picture in a TV show last night!

I know it might sound anal retentive, but I keep an accounting sheet of the number of rounds fired on most of the rifles I use..
to include load history...

I also sort brass into lot numbers and put them in a zip lock freezer bag, with a 3 x 5 card in there, to record the life history of that lot of brass...I record the charge, the bullet used, the primer used and if the brass was necked sized or full length sized.. and the date of assemble for each load...

It gives me a good guideline of what is going on with each rifle...

My latest experiment is keeping track of records on how many reloads can one get reliably out of a batch of brass.. they are in lots of 10.. I am recording when I do what..

Using Lee Collet Neck Sizing Die, a REdding body die, and annealing the cases.. right now I am on the 37th reload to a batch of Remington brass in 223...

Stretching out the reloading dollars and also getting around the components shortage as much as possbile...at least with the brass part of it..

Serious target shooters and most military teams keep barrel logs to keep track of the number of rounds fired and the dates of scheduled scrubbings, soakings, etc. It's quite routine.

Mark

Some years ago when I shot a lot of highpower matches (won my share of 'em, too), this subject came up. Over a period of a few years, I asked folks around the country how long their barrels lasted before they replaced 'em. People asked were those with the lowest NRA classification and scores up through the top ones that won or placed in the top 5% in most of the matches with the best scores.

Those using the .308 Win. burning about 42 grains of various powders: best shooters rebarreled at about 3000 rounds, worst at 6000.

Same folks asked about the 30 caliber magnums burning 65-70 grains of powder; top shooters put a new tube on at 1200 rounds; the ner-do-well ones about 3000 rounds.

When the 7mm Rem Mag got popular, those winning matches rebarreled 'em at 800 rounds. those shooting the worst scores at 2000.

Interesting that a few shot the .264 Win Mag and got 600 rounds of accurate life before getting a new barrel if they won matches. If they didn't win or even place well, they didn't rebarrel at all.

After the .243 Win. became popular, folks taking home all the marbles rebarreled at 1500 rounds, those loosing all their marbles did it at 3000 rounds.

This led me to believe (and top competitive shooters agree), ones ability to tell when a barrel should be replaced is directly related to how well they can shoot. Those who shoot well rebarrel often 'cause they can tell (or know) when they start going bad, those who don't, don't.

Bart B.'s info is spot on.

If a hunter takes good care of his barrel, does not get it very hot when testing loads, and does not ruin it by bad cleaning technique, does not let it rust in the field, his barrel life will be longer while still giving acceptable hunting accuracy.