Heavier for caliber bullets = more or less barrel life?

[Winny94]

I try to not say much on this site as it seems everyone knows so much more than I do, I just like to read and learn, but have a (potentially) stupid question I need a straight answer to.
Do heavier for caliber bullets extend or diminish average barrel life?

Over on snipershide, the general attitude seems to be light bullet pushed very fast is harder on the throat than a heavier bullet pushed slower (all else being equal). Ive read several times on here just the opposite. Its odd that 2 large groups of people have such opposing views - which thinking is correct and why?

thanks a lot!

 

[dcali]

I've always assumed that heavies are worse because barrel time is longer- there is more time for the gas to transmit heat to the bore for each shot. That would be consistent with the relatively low barrel life typically seen by F Class shooters pushing 200s out of .308s. I can't think of a reason that lighter bullets would hurt barrels more, other than that they typically use slightly more powder per shot, all else equal. The two effects would tend to cancel each other out.

That said, it's hard to say much definitively about barrel life (defined the way that we do), because there is so much going on and it's really hard to say. I'm just speculating.

 

[6ShotsOr5?]

There’s a lot of interesting old reports on stuff like this from Aberdeen Proving Ground or other ballistics facilities that show up if you do some Googling. Many of the studies are for larger caliber stuff like various artillery bores, but you might find some past research that helps.

 

[ben_g]

Here in Australia there is a popular class called F-standard. They are restricted to 155gr bullets in their 308’s

On average F-standard shooters report greater barrel life than FTR shooters using heavy pills.

It’s the heat and pressure that wears a barrel, I’m not convinced its the velocity. The projectile is moving it’s fastest in the last half of the barrel, but when you look at a barrel showing wear the firecracking and damage is in the first several inches not near the muzzle.

 

[FrankG]

Here in Australia there is a popular class called F-standard. They are restricted to 155gr bullets in their 308’s

On average F-standard shooters report greater barrel life than FTR shooters using heavy pills.

It’s the heat and pressure that wears a barrel, I’m not convinced its the velocity. The projectile is moving it’s fastest in the last half of the barrel, but when you look at a barrel showing wear the firecracking and damage is in the first several inches not near the muzzle.

Yes heat and pressure does effect and wear the barrel and I’ll add to this.

Also type of powder being used effects barrel wear. The double based powders are harder on the barrels. They typically produce a higher flame temperature.

Flame temperature in the throat area if I remember correctly with all the variables involved will run from around 2200 to 4000 degrees F if I recall correctly. 2200 degrees is the temperature of lava. Yes it only happens for milliseconds but there is no way around that instant blow torch going off other than not pulling the trigger.

Bullets....yes bullets have an effect on barrel life as well. In the same caliber and lets just use .30cal for example a 155gr bullet has less bearing surface area compared to a heavier 175gr or 190gr bullet etc...the heavier bullet with the longer bearing surface area will have an effect on shortening barrel life. I don’t have hard numbers I can give you like 10% shorter barrel life etc...but it has been proven that it does shorten barrel life.

My friend Dave Tooley always uses the same old saying, “It cost money to go fast!” We all pay for it one way or another.

Either by increasing case capacity to get a higher velocity, types of powder, types of bullets, rate of fire as to how you cycle the bolt/rifle and how hot you get the barrel one way or another we all pay for it.

Later, Frank
Bartlein Barrels

 

[hammerjack]

I would think it would be less life as long as it has a longer bearing surface

 

[linebaugh]

There is no straight forward answer. Cooler powders will help but are typically not very temp stable. Keeping the pressure down a bit will help.

There are more varisbles at play than you can put thoughts together to explain. Just shoot and consider barrels a consumable product like reloading components or like tires. You don't buy a car asking questions about tire life to make that purchasing decision. You just know the tires will go bad in time and will need replaced.

 

[Grimstod]

Well it depends.

Slower powers used with heavier bullets tend to burn cooler and the spread of the heat is through out more of the barrel compared to lighter bullets and faster powders.

Lighter bullets though have a shorter bearing surface and that means less friction. Longer bullet longer bearing surface and more friction. It especially takes more for the lands to engrave the longer bullet. This is my reason that I believe that longer heavier bullet erode the throat faster.

In the end this seams like a math question and not a philosophical one. At least not at any level I have examined it in. Can the powders lower temperature justify the greater friction of the bullet. Mind dazzled at the possibilities of discussion here

 

[ShootDots]

I am not sure that heavy-for-caliber bullets are harder on barrels than a light-for-caliber bullets. I look at this in a different light. VERY overbore cartridges burn up barrels very fast and they usually use slow(er) powders. Whether they are using a heavy or light for caliber bullet does not seem to matter>>>it is the overbore with a HUGE flame coming out of a smaller neck. Most overbores operate at high pressure. I bet that if you took a 500gr bullet out of a .458 Win Mag it will last considerably longer than the exact same case, now necked down to .264 shooting 160 class bullets. I think very high pressure, overbore cartridges and high sustained rates of fire will rapidly destroy a barrel>>>>whether it is using a heavy or light bullet! Then, as wisely mentioned earlier, the powder used is also a large contributing factor. Suffice to say that some disciplines are going to burn barrels up A LOT faster than others. If you are not willing to spend the money on the necessary barrels, I would suggest moving to a different discipline..

 

[JFW]

This article really tells you how short life is.
https://www.accurateshooter.com/technical-articles/facts-about-barrel-life/

 

[mtnman31]

I think it really boils down to bullet construction, pressure, and heat. As mentioned, generally speaking, when people are using a heavy for caliber bullet, they are generating more heat and pressure (slower powders) to try and maximize velocity. Additionally, the bullet will have a greater bearing surface that increases barrel wear. You can push heavy bullets all day long at slower speeds (lower pressures) and I don't think your barrel wear will be noticeably increased over a lighter bullet, even with the greater bullet bearing surface. Just remember, barrels are a consumable item.

If you want to maximize barrel life shoot cast lead bullets through your rifle. I say that with a touch of sarcasm, but it is true and why I generally only shoot lead through my older firearms (antiques and older surplus rifles).

 

[gunsandgunsmithing]

the br family of cartridges, bullets and powders probably has a lot to offer toward answering this question. Just look at a 6br with light and heavy bullets and then look at a 30br.

 

[ShootDots]

the br family of cartridges, bullets and powders probably has a lot to offer toward answering this question. Just look at a 6br with light and heavy bullets and then look at a 30br.

Exactly! The 30BR could hardly be called "overbore".. But the same case necked down to 6mm is "more overbore" by far than the 30BR..

 

[Longrange57]

Exactly! The 30BR could hardly be called "overbore".. But the same case necked down to 6mm is "more overbore" by far than the 30BR..

Very good question and some very good observations. damoncali....so much going on its hard to say...boy do I agree! FrankG...great response! linbaugh....you just know the tires go bad in time....thats great! gunsandgunsmithing....6 vs 30 BR great analogy! shootDots....always has the logical answer! Like a good old friend of mine once said...group size usually dictates, not barrel life!

 

[FrankG]

Exactly! The 30BR could hardly be called "overbore".. But the same case necked down to 6mm is "more overbore" by far than the 30BR..

Bingo! Say it all the time.

Staying with the same caliber... a .308win vs a .300wm. Even if you run the same bullet the WM is going to toast the barrel faster. No way around it.

6BR vs a .243win. Same thing is going to happen as above.

Take the .308win case and neck it down to a 6.5mm or a 6mm but your still using the same case capacity. So in essence you’ve turned the 6mm or 6.5mm into a magnum round it same effect. Shortens barrel life because by reducing the bore size you have to funnel the powder down a smaller hole.

Now figure in the types of bullets, type of powder etc...etc...etc...and you will have even more effects/variables that can work against you even more.

 

[Longrange57]

Bingo! Say it all the time.

Staying with the same caliber... a .308win vs a .300wm. Even if you run the same bullet the WM is going to toast the barrel faster. No way around it.

6BR vs a .243win. Same thing is going to happen as above.

Take the .308win case and neck it down to a 6.5mm or a 6mm but your still using the same case capacity. So in essence you’ve turned the 6mm or 6.5mm into a magnum round it same effect. Shortens barrel life because by reducing the bore size you have to funnel the powder down a smaller hole.

Now figure in the types of bullets, type of powder etc...etc...etc...and you will have even more effects/variables that can work against you even more.

Agree with all the above....just something to think about!

 

[gunsandgunsmithing]

I'd love to know who wrote that. It's the best read on the subject I've ever seen but leaves a lot of questions. Nevertheless, thank you for posting it!--Mike Ezell

 

[Longrange57]

I'd love to know who wrote that. It's the best read on the subject I've ever seen but leaves a lot of questions. Nevertheless, thank you for posting it!--Mike Ezell

I put it together a couple of years ago for a group of friends. I had notes from the powder manufacturers that had been gathered and many of us had suspicions of mechanical abrasion being a bigger problem than we often want to admit. Manufacturers could prove up many things but it may not be in their best interest!

 

[Beau]

It's all about heat. Heavier bullets stay in the throat longer (dwell time) and allow the heat more time to soak into the barrel steel. Lighter bullets spend less time in the throat, presenting less opportunity for the heat to soak into the steel.

I guarantee you can make a barrel last longer by doing 3 things:
1) Use a lighter bullet with a shorter bearing surface
2) Use a powder with lower heat potential and
3) Use a bullet lube like Moly or Danzac.

 

[DukeDuke]

The heat is what kills the barrels not the bearing surface, with enough time and dedication you can damage your barrel within 3 range sessions regardless of the caliber or bullet. Frequent long firing strings will do bad bad things to the bore. Hypothetically, pick a rifle caliber and a bullet, fire it once every 20 min. every time you go to the range, so we are talking about 15 shots a day, do this daily for a year /I wish!/, we have 5474 rounds thru the barrel, then borescope it. What would the throat look like?