What determines a barrels life?
- Thread starter Feo3086.5
- Start date
The properties of the steel of that specific barrel matters.
The properties of the machining of the bore matters.
Your throat dimensions matter.
Your rate of fire matters.
How hot your load matters.
Cleaning matters.
Your standards for accuracy matters.
Basically every little thing matters and nobody can predict when a barrel will go out, you might get close with generalizations but I have read of F TR shooters retiring a barrel after 1500 rounds but if you look at other forums the venerable 308 lasts 5000+ rounds.
The properties of the machining of the bore matters.
Your throat dimensions matter.
Your rate of fire matters.
How hot your load matters.
Cleaning matters.
Your standards for accuracy matters.
Basically every little thing matters and nobody can predict when a barrel will go out, you might get close with generalizations but I have read of F TR shooters retiring a barrel after 1500 rounds but if you look at other forums the venerable 308 lasts 5000+ rounds.
I cant remember where but there is an excel file floating around the forums that give a prediction based off of your caliber, pressure, powder, charge weight, etc. All stuff you can get off quick load.
Not sure how accurate it is but talking with 2 buddies who exclusively ran the same load from break in to barrel death were +/-50rds of the prediction in about 4 barrels worth of data. I have 2 of my barrels in 6.5 and 308 I am testing this on using the same load from start and well see how it does. Predicts the 6.5 with my load to die at about 1900 and change and I'm at 1700 so well see, did recently tweak the load due to a velocity loss so it may be almost time. 308 I have 2000rds on and I have a bit of time to go...thats my long road test.
Not sure how accurate it is but talking with 2 buddies who exclusively ran the same load from break in to barrel death were +/-50rds of the prediction in about 4 barrels worth of data. I have 2 of my barrels in 6.5 and 308 I am testing this on using the same load from start and well see how it does. Predicts the 6.5 with my load to die at about 1900 and change and I'm at 1700 so well see, did recently tweak the load due to a velocity loss so it may be almost time. 308 I have 2000rds on and I have a bit of time to go...thats my long road test.
Heat, caliber, pressure, bullet weight, barrel quality, cleaning ect all factor in. Expectations can be a big one.
I had a 6mm remington vls that after 900 or so rounds started sending random fliers and eventually opened up to 1.5 or so groups. I shot hot loads through it. I sold it to a gentleman with full disclosure about it, he never rebarreled it and still shoots it regularly. His statement was its hard to burnout a modern barrel (stupid statement). But to his expectations the barrel was still good.
Most of my shooter garands/03's have terrible barrels on them from being cleaned with sectional rods. They swallow the muzzle gauge but they still work well enough to plink.
30 cal except for the magnums seem to last a while. No experience with 6.5 though I figure it should be better than 6mm/243.
I had a 6mm remington vls that after 900 or so rounds started sending random fliers and eventually opened up to 1.5 or so groups. I shot hot loads through it. I sold it to a gentleman with full disclosure about it, he never rebarreled it and still shoots it regularly. His statement was its hard to burnout a modern barrel (stupid statement). But to his expectations the barrel was still good.
Most of my shooter garands/03's have terrible barrels on them from being cleaned with sectional rods. They swallow the muzzle gauge but they still work well enough to plink.
30 cal except for the magnums seem to last a while. No experience with 6.5 though I figure it should be better than 6mm/243.
The more powder that you try to shove down the smaller hole quicker it will erode. That’s pretty much it.
Ah, the old "nature vs. nurture" discussion. While an argument could be made that the material properties of the barrel (material from which it's made, method of rifling (CHF, etc...), and/or material treatment (melonite, etc...)) play a role, it seems that a bigger role is played by the manner in which the barrel is used (big powder charge with a (relatively) small bore, high rate of fire, etc...).
By and large, an argument could be made that "speed kills"; this can be applied to both projectile velocity and rate of fire.
By and large, an argument could be made that "speed kills"; this can be applied to both projectile velocity and rate of fire.
Usually I shoot both of my rifles on Sunday, the 308 first for 5 rounds then the 6.5 rounds, at the range I shoot at they are 15 minute intervals, so during the break the. Barrels cool off, then 10 rounds again, I usually end the day at 30 to rounds through both of them. I’m just trying to group my shots with the different loads I’m loading to see which is best.
I read an interesting analysis recently that correlated chamber pressure with barrel life. Look at pressures for calibers with an expected long life - .308 and .223, for example, with 5000 rounds or more pretty much a rule of thumb for standard loads - compared to 6.5CM (2500 rounds +/-), 6CM (1500-2000), etc.
So, this. High powder-to-bore ratios coupled with resistance added by the fast twist rates required by long, skinny high-BC bullets equals faster barrel toast.
Pressure is the quiet killer. Heat is the loud one. But either way, projecting a barrel’s life is an exercise in futility.
If you want to geek out, this is worth your time:
Thank you for posting this excellent and informative article! Some of the conclusions run counter to long-held belief systems regarding barrel erosion. However, the findings regarding gas blowby around a non-obdurated bullet directly relate to the negative effects of excessive headspace. Unfortunate that the gist of the article concentrated on large artillery. When I get some time, I am going to develop a spreadsheet using the constitutive formulae for wear presented in this article.
@Rotnguns - I thought the article did justice to the chemical reactions that lead to erosion of the bore and how they relate to the effects of heat and pressure. Look at the relationship between erosion and fatigue going from the 105mm to the 155mm artillery - the ratio of powder mass to bore size tilts to powder mass and the relationship between cycling out versus wearing out inverts.
recent article in guns & ammo looked at gas blow by, suggesting that accuracy may fade as the barrel wears and allows more gas around the bullet, also suggesting a flat tail bullet may help when accuracy starts to go on a worn barrel with boat tail bullets.
i have no real opinion on this...just sharing.
i have no real opinion on this...just sharing.
