Barrel Life

[Bad Ass Wallace]

I have a number of military rifles that I dedicate to shooting only cast boolits. 7mm, 8mm, 30.06 and 303 all are reserved for cast boolits ONLY. Then there is my Winchester collection, 25/20, 32/20, 38/40, 44/40, 32/40 and 38/55, all never see anything but cast boolits. I once shot "J" boolits through the 30.06 and it was quite a long time and several cleanings before the guilt edged accuracy returned.

Now I keep my 'J' boolit rifles and " ONLY cast " seperated in order to prolong the excellent accuracy that I have managed to achieve.



Just like any rifle, they will wear out eventually, but how many rounds will that take? Those who compete regularly in cast competitions would be wise.

[Winger Ed.]

In one of the Lyman books, there is a article where they took a new .30cal. Win. Model 70,
fired 40,000 rounds of cast. Then ground off the top of the chamber/barrel to look of throat erosion and loss of rifling.
They detected 'no noticeable wear'.

With jacketed, there are lots of variables.
But ya often hear that peak accuracy starts going away between 2-3000 shots due to throat erosion depending on caliber,
hot loads, strings of rapid fire, etc. If you work at it, you can trash a barrel in a few hundred rounds or so.
Some seem to live forever if you seat the bullet out a little farther. Your mileage may vary..

I've got a old top eject Winchester .30-30 that had been fired about 5 times before I got it.
I've fired it a fair amount, but only with cast & near max. of IMR 3031, and never let it get too hot to hold the barrel.
The inside of the barrel still has what looks like all of the factory bluing.

[Larry Gibson]

It's the erosion of high pressure, high temperature gas that erodes the throats. Friction from a jacketed bullet has little impact on erosion. I have fired over 3100 rounds through my 30x60 XCB rifle now using just cast bullets. However, these loads [mostly 54 gr AA4350 under the 165 gr XCB bullet] were high velocity with an attending measured pressure of 50,000 psi. That and the fact for much of the year here in the desert of western Arizona the barrel never really cools much down no matter how much time is given between shots. Point is, there is throat erosion in the barrel now.

With normal cast bullet loads using 1/2 or less of a powder charge and half or less pressure any erosion will be minimal if any at all.

[Gewehr-Guy]

One of our CBA match shooters uses a Smith Corona 03A3, with a 6 groove barrel. He has shot over 30,000 rounds through it, and it has enough throat erosion that he seats his 311299 bullets too the top of the gas check, too maintain it's accuracy. His loads are around 19 grs of 4759

[RyanJames170]

One of our CBA match shooters uses a Smith Corona 03A3, with a 6 groove barrel. He has shot over 30,000 rounds through it, and it has enough throat erosion that he seats his 311299 bullets too the top of the gas check, too maintain it's accuracy. His loads are around 19 grs of 4759

Far longer barrel life then would be with a M2 ball clone.

[Whole Bunches]

I gage the throat wear on as many bbls as I have gages to fit. My normal rifle cast bullet loads are in the 1400-1800fps range, typically with 15-16gr 2400 with some exceptions such as 20-27gr AA2200. I can’t find any measurable wear so far. This is with 30 cal and 303 cal rifles, 2,4,5 groove bbls. Bbls never get real hot, cooling to ambient temp after each five shots.

However, I did do a M1 rifle test. In order to get enough oomph to function and fine accuracy, I used 35gr IMR4895 and Lyman 311291. My normal M1 load is 46gr IMR4895 with 172-173gr M1/M72 fmj bullets. In a 600 round test each of these two loads, the cast bullet load gave 1/3rd the wear of the jacketed bullet load. The bbl never got real hot by letting it cool to ambient temp after each 8 shots. Testing took place over a couple of months. I assume the bbl wear with cast was due to higher pressure and amount of powder than my normal mild loads with half the amount of powder. And, of course, the jacketed load used even more powder and pressure. When I think about it, my results make sense to me.

I enjoy keeping such records. Then there’s my results of shooting 10’s of thousands of 300 Blackout rounds testing bbl steel and bore treatments, but that’s for another time.

[35 Rem]

In one of the Lyman books, there is a article where they took a new .30cal. Win. Model 70,
fired 40,000 rounds of cast. Then ground off the top of the chamber/barrel to look of throat erosion and loss of rifling.
They detected 'no noticeable wear'.

With jacketed, there are lots of variables.
But ya often hear that peak accuracy starts going away between 2-3000 shots due to throat erosion depending on caliber,
hot loads, strings of rapid fire, etc. If you work at it, you can trash a barrel in a few hundred rounds or so.
Some seem to live forever if you seat the bullet out a little farther. Your mileage may vary..

I've got a old top eject Winchester .30-30 that had been fired about 5 times before I got it.
I've fired it a fair amount, but only with cast & near max. of IMR 3031, and never let it get too hot to hold the barrel.
The inside of the barrel still has what looks like all of the factory bluing.

In light of the other comments mentioning a significant connection between pressure and throat wear even with cast bullets, it would be interesting to find that article to see what loads they were using with the 40,000 rounds.

Also would be interesting to see if there have been any tests done to show a difference in actual rifling wear between jacketed and cast. Say in a 30-30 where the loads could be virtually identical to remove pressure and heat from the variables and measure just wear from each bullet.

[30calflash]

Large charges of slow burning powder behind a heavy for the caliber bullet is a major contributor to barrel erosion. That and rapid fire, such as in an 80 round NMC, will also contribute due to heat build up and erosion.

Col. Harrison of the NRA said a good barrel won't wear appreciably with cast loads. His tests were mostly with lower power accuracy oriented ammo to help get cast shooting back on track after WW2. His 'heavy' loads were in the 2000 to 2300 FPS range and would probably erode some.

[Whole Bunches]

I was asked what gauge I use in the 303. I use a USGI Gauge, Breech Bore, Taper, Cal 30, C-3940. Take and write down reading. Keep track of rounds and bullets fired. Take new readings to see if any measurable wear and record subsequent readings. Keeping records is part of my shooting that I also enjoy. British SMLE/Enfield 303 gauges are sold by BRPGUNS.COM if you want the British pass/fail type of gauge.

[RyanJames170]

I wonder if in the case of cast bullets if it is the amount of powder being burned or if it is the speed of the bullet going up the barrel as I assume most bullets of any major velocity have a gas check.

I also wonder what the threshold is for velocity or powder volume where wear starts to happen

[Larry Gibson]

Has to do with pressure and heat; how much pressure the length of the time/pressure curve (as in how much powder is burning up the barrel) and how hot the barrel gets. The speed of the bullet as in friction, is negligeable with cast bullets. Even those with GCs.

[TNsailorman]

Larry, as usual, is correct on this. Pressure and heat are the most causes for barrel erosion. Especially slow burning powder like 450 and 4831 in small caliber (think 25-06, 6mm-06, etc.). I heard it stated one time that 4831 in a 25-06 was like putting a blow torch in the chamber and giving the barrel a quick shot of hot gas. I saw a picture of the throat of a 25-06 one time that the barrel just ahead of the chamber looked like a soft river bank just after a spring flood. Grooves cut into the metal everywhere. Throat completely washed out after a stated 1500 rounds or so of lightweight bullets used on varmints. One of the most notorious actors according to writers in the magazines was the 6.5 Winchester magnum. Reports of the throat being completely wash out after less than 1000 rounds. No personal experience with the 6.5 magnum but I can believe it. james

[RyanJames170]

Has to do with pressure and heat; how much pressure the length of the time/pressure curve (as in how much powder is burning up the barrel) and how hot the barrel gets. The speed of the bullet as in friction, is negligeable with cast bullets. Even those with GCs.

Now for a given velocity would a person be better off with a higher pressure with less powder or less pressure but more powder being used, case being pistol powder vs fast/medium burning rifle powder vs perhaps a slow powder..

I ask out of curiosity, as I know you can get say 1700 fps with many different powders in a given 30 cal rifle cartridge how ever the pistol powder using maybe 14gr of powder will be at a higher pressure then say 2400 or IMR4198 or IMR4895 how ever the charge weights will be a lot more then the the fast burning pistol powder.

[country gent]

Powder charge, burn rate, bullet weight, style, Barrel material, rifling form and type ( grooves and twist rate). all fall into this. Then comes use and expectations and needed performance.
Powder type is a big culprit and the slow burners transfer more heat to the barrel than the faster spreading the area.

There used to be a surplus powder sold by Bartletts, USGI 380 It was a ball powder and slightly slower than H380. It was a popular powder among NRA service rifle shooters. It tended to burn out the barrels ahead of the throats up to around the gas port on the M1A. I sectioned a M1A stainless barrel that had shot this powder its life of 4500 rounds. Not only ahead of the throat was the dried out river bed, but the gas port had around a .030 radius burned on the edge all around. There was erosion showing in the barrel to the gas port. My gunsmith used this barrel to show the erosion to customers.
I also believe boattails may be harder than the flat based versions, as the boattails may concentrate heart flame and pressure against the barrel more.

Performance is a consideration here also. The benchrest competitor needing to shoot low .2-.1 groups barrel isnt going to last as long as the high power shooter who is wanting 1/2-3/4 moa. The Varmint hunter wanting minute of wood chuck barrel is going to last longer still and the deer hunters longer yet.

For a few years I shot 243 across the coarse and 1000 yds. This was a 1-8 twist barrel 26" long tight necked chamber at .267. for 600 yds and 1000yds I shot JLK 105 grn, 105 grn Bergers and 107 sierras. I also played with some 107 Starke flat based. 200 and 300 yds were 87 grn hornadies or sierras. usually between 2300 and 2500 rounds the barrel would start loosing X ring count. My M!As in 308 would start loosing X count around 35-3700 rounds at 600 yds. Ive heard that a 300 win mag built for 1000yd matches has 900-1000 rounds of premium shots then its going to start dropping off accuracy wise.

[charlie b]

Now for a given velocity would a person be better off with a higher pressure with less powder or less pressure but more powder being used, case being pistol powder vs fast/medium burning rifle powder vs perhaps a slow powder..

I ask out of curiosity, as I know you can get say 1700 fps with many different powders in a given 30 cal rifle cartridge how ever the pistol powder using maybe 14gr of powder will be at a higher pressure then say 2400 or IMR4198 or IMR4895 how ever the charge weights will be a lot more then the the fast burning pistol powder.

IMHO, the erosion is due to the mass of the combustibles and their velocity as they go through the throat. Which is why 'overbore' cartridges tend to be 'barrel burners'. If you can get the same or near same vel with less powder then it will be less hard on the throat.

So I would say the lighter charges of pistol powders will be 'easier' on the barrel because of less combustibles going through the throat. But, the key is consistency. 2400 seems to be a stand out in that regard. But, I don't think you will wear out a barrel with any of them in the cast bullet velocity range.

[M-Tecs]

The OP put this in the cast section. Barrel life has many variables and outcomes. What true for a 45ACP verse a 357 Mag with max charges of Little Gun verse a 6mm rifle cartridges may not be the same.

A couple of examples. Back in the mid-70's I purchased a high end Bulleye 1911 for one of the nation's premier builders. He stated using jacketed I should see around 50K barrel life. With cast he stated 500K was not unusual.

From first-hand experience with NRA match rifles sometimes large cartridges with slower lower temp powders gives better usable barrel life. The 6mm Competition Match generally doubles barrel life over the 243 Winchester. The 6mm Competition Match achieved that via changing the vortex angle of the neck and using slower cooler burning powder.

https://bulletin.accurateshooter.com...etition-match/
6mm Competition Match Cartridge — Slower Powder Yields Better Barrel Life
My dad was shooting a 6XC for a while and was getting tired of going through almost two barrels a year. So, he came up with the 6mm Competition Match. Like I said, it is a .243 Winchester with a 31-degree shoulder. This delivers the same (if not better) velocity as the other popular 6mm cartridges, but we get almost double the barrel life because we increased the case capacity, so we can shoot a slower burning powder. The barrel I took to Camp Perry that won the CMP Cup had over 3700 rounds on it when I was finished. [EDITOR: Take note readers! Most 6mm barrels are toast after 2500 rounds.] Granted it definitely needed to come off at that point, but it obviously was still shooting well enough to win!

[Bigslug]

A lot of variables, but figure that a meticulous, log-book keeping, clean-every-X-number of rounds sniper shooting factory jacketed match .308 through a match barrel would likely lose match accuracy between 10,000 and 20,000 rounds. You can safely assume that the barrel would be "good enough" for less demanding roles long after that. The loads we're all using to shoot cast to @ 2,000 FPS out of 20th Century military bolt gun cartridges are WAY less intense.

In doing armory work on AR-15 family rifles, I've acquired a couple of different 5.56mm throat erosion gauges. The commercial/civilian version gives a starting line and then about 10-15 lines spaced a tenth of an inch apart that would indicating up to maybe one to one-and-a-half inches of burnout before you get to touching the .219" bore diameter again. The MILITARY throat erosion gauge is a different matter entirely. As I recall, it goes over three inches from the starting index to where the tag says "Don't deploy overseas if it reads past this mark", which means to say you can still train with it, just don't go to war with it. For point of reference, the SWAT rifles (chrome-lined Colts) I examined that had been in service for about a decade of bi-weekly training with full-pressure 5.56 NATO ammo, lackadaisical maintenance, and probably more that a little full-auto fun shooting all still registered well within the boundaries of the "civilian" gauge. I think 0.7" of wear was the worst of them.

As for your 1870's/1880's cartridges. . . I am reminded of an article written in probably the 1990's by Kevin Thomas about his time working for Sierra bullets on the subject of load intensity and barrel wear. He described Sierra's use of a dedicated firing fixture to perform quality control accuracy testing on every lot of their jacketed .45ACP match bullets. They'd been using that barrel for decades before he got there and were still using it when he left. They may be using it still. Similarly, our SWAT guys ran 9mm MP-5's for 20 years before I arrived - the reciprocating parts of the gun took more of a beating than the barrel ever showed any sign of. Good luck killing the barrel of any pistol-caliber firearm with shooting - jacketed or cast.

Suffice to say, if you're spreading your shooting around multiple rifles, you'll probably not live long enough to wear them out with cast. Especially if you can use the trick of changing your mold spec to maintain fit - the 311299/314299/316299 family being an obvious example of how one might chase a flamed-out throat past the point where fiddling with seating depth is no longer getting it done. More cowbell? NAH! MORE OGIVE!

[M-Tecs]

A lot of variables, but figure that a meticulous, log-book keeping, clean-every-X-number of rounds sniper shooting factory jacketed match .308 through a match barrel would likely lose match accuracy between 10,000 and 20,000 rounds.

The 308 was/is the standard for NRA match, service rifle and Palma rifle since the 60's. Lots and lots of actual documented history. Competitive accuracy for NRA Highpower for the 308 is normal between 2,500 and 3,500 rounds before holding elevation at 600 yards becomes an issue. Some a little less and some a little more. Normal average hunting accuracy will be more.

As the throat becomes more and more heat checked you start dropping the occasional shot low followed be general opening of the groups.

Some good info here:

https://bulletin.accurateshooter.com...s-key-factors/

https://bulletin.accurateshooter.com...l-life-report/

https://www.rifletalks.com/equipment...e-barrel-life/

Police snipes for the most part are not good shooters. The only ones that were high school or colleges small bore shooters or they current accuracy-based rifle competitors.

Through the years I've seen about 3 dozen urban SWAT team members show up at High power matches. Some even apologized beforehand about the clock cleaning they would be handing out. After the match most never came back since their egos could not handle finishing at or near the bottom.

The average police sniper shot is 51 yards. https://www.policemag.com/special-un...y%2051%20yards.

[nueces5]

The math is correct, I have my CZ 550 Varmint with approximately 3000 shots fired
Half of them must be with FMJ, and the other half with cast.
Now its usual 0.7 MOA is already at 1 MOA and I can't find much way to lower it. Yesterday I bought a box of Federal Gold Medal, let's see if I'm the one who's having the problem reloading, a friend told me that instead of a box of Federal Gold Medal, I should have bought a Bartlein barrel.

[M-Tecs]

The math is correct, I have my CZ 550 Varmint with approximately 3000 shots fired
Half of them must be with FMJ, and the other half with cast.
Now its usual 0.7 MOA is already at 1 MOA and I can't find much way to lower it. Yesterday I bought a box of Federal Gold Medal, let's see if I'm the one who's having the problem reloading, a friend told me that instead of a box of Federal Gold Medal, I should have bought a Bartlein barrel.

While it seems counter intuitive abrasive bore cleaners used every couple of hundred rounds improves and extends usable barrel life.

I recommend Flitz or IOSSO. https://www.amazon.com/flitz-bore-cl...z+bore+cleaner