What is the life of a rifle barrel?

At the local range recently I had a discussion with a mate regarding my selection of a suitable cartridge for a new custom bench-rest rifle that I am organising to have built by a gunsmith. It is required to put 5 holes in a target at 300m to an accuracy of 0.75" or better. As it will not be cheap it would nice if it lasts for a few years.

We got around to talking about barrel life and so I did some sums.

The results were quite interesting.

Anyone want to hazard a guess how long a barrel will last?

(Using a typical calibre, .223", 24" barrel at a muzzle velocity of 3,600ft/sec)

* Danny M *

I'm pretty sure it should be good for those 5 holes. D'ya want to borrow a cordless drill?

I think it is only a matter of seconds.

Mike.

Interesting question !!

My only benchmark was the spotting rifle in LAW 80, so I cheated

**LINK**

MichaelG.

I've seen some fairly old full bore (nato 7.62mm) target rifles being used that were still clearly pretty accurate - only variation due to cross wind when conditions are like that. They start at 300m and then go longer.

The barrels do get changed as some point but as they are generally only used for competition shooting I'd guess 10 to 15 years as there are only so many ranges, some will be too far away for people to travel so I doubt if they are shot every month. This sort of shooting allows 2 sighters before the ones that count are shot. So going on that some where in the region of 1500 rounds plus or minus ??. That;s assuming 300 and 600 are shot every time. Some ranges do another longer distance as well. That might push it up to 2000 rounds.

John

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First off Danny, what is the barrel made of. Stainless steel or a specified normal rifle barrel steel.

If stainless I would give it at least 20,000 rounds of NORMAL loads but if loaded with extreme loads then some 5 to 7000 rounds.

The normal steel barrel is subject to leed erosion and I give that about half the life of stainless steel barrel.

Then you come to the configuration of the leed, bullet touching the start of rifling or perhaps a 1 x cal. jump? as per Weatherbys. with about a 3 cal. jump. Best choice in normal loads is touching the rifling.

Now we come to Cal, you mention .223 which at a stretch with normal military loads will group 9" at 300 meters, The rise and fall of a .223 is nine inches at 300.Small bullet subject to outside influence like side wind.

The small cases are subject to variations in internal volume so case selection is important, also sizing. Neck sizing is another variable so neck trimming is needed for consistency. and so it goes on until you achieve a desired result.

Now we talk about barrels and rifling twist against bullet weight, 1 in 12 twist will be OK for 55 gn. bullets but heavier bullets need 1 in 7 twist.for 90 gns.

It can be an expensive deal to find that the new barrel is no good at 300 but very good at 100.

Having reloaded for a Ruger Mini 14 stainless barrel. I found that at higher end loads were not accurate but standard loads were very good, grouping was variable due again to outside influence.

>22 calibre is not a good accuracy barrel but go to a wildcat in 6mm with a large volume case then it all changes. and you will achieve 3600 fps easily with accuracy.

Both Michael's - Well done - You get the bananas!

Yep, less than 10 seconds.

Nice to see that there are practical thinking people on this forum.

(I settled for a .223" in preference to a 6BR in the end as the barrel lasts for a few more seconds, just have to read the wind a bit better).

* Danny M *

Just to add that a 120mm tank gun barrel is good for 20.000 efc's for standard loads but using APDS it comes down to 170 efc's. barrel erosion is the culprit. Plus the wear from the Sabot that carries the APDS. projectile.

A 155mm barrel in an M109 Howitzer is OK for 20.000 as it is not stressed with high pressure loads.

LOL I don't think life in terms of how much time the bullet spends travelling down the barrel is practical at all. I'd me more concerned about how often I would have to buy a new one.

John

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Danny,

Please can you explain exactly what you mean by barrel life. Do you mean before it loses accuracy?

I would have thought a rifle barrel lasts until something happens to put it "out of proof "

Eric

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Depends on quite a few factors.

The obvious one being velocity and bullet choice.

At the bottom end of the scale we have sub-sonic lead .22LR ammo wher the barrel will last many, many 1000's of rounds.

At the other end of the scale we have something like a .220 swift which can chew through barrels at an alarming rate. They are however not a popular choice these days. But .243's which are have a reputation for having quite a short barrel life are.

Basically any cartridge that has a ratio of a large charge to a small bore is prone to burning the throat out. So something like the .220 swift is very bad but the good ole 30-06 is quite good. - For those that don't know a .220 swift uses a 30-06 parent cartridge necked down to .22. In a similar way a .243 is a necked down .308 which is the civilian designation of the 7.62mm NATO round. These are also reasonably barrel kind.

Cleaning and method can also be barrel killers. The drawstring type used by the military for its compactness is very bad as the chord rubs and wears the muzzle and barrel crown unless it is drawn through totally square. (which is virtually impossible) Also unless a carbon steel barrel is cleaned on a regular basis the wash of copper left by the bullet will cause an electrolytic reaction with the steel (not a strong one but over time) and cause pitting.

There are many other things such as the barrel twist rate that can have influence. And of course what the chosen barrel has been made from.

Nick

My memory of full bore target shooting (now very distant) was that the barrel was always cleaned as soon as possible after shooting to remove the residue from the bullet and primer. A cleaning rod was used, never a pull through, with a cotton patch soaked in ammonia (if I remember correctly). Afterwards dry and then oiled patches were used. 22LR target rifle barrels were generally not cleaned until one started getting bad scores. Then it was just a dry patch not followed by oil but a couple of rounds.

I am sure this has all changed with the advent of modern cleaning chemicals.

JA

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Ja, that was the case when I was shooting.

I however did not do much target shooting. Mine was either foxes (on a regular basis) or deer stalking (not as often)

Very often when I had been out foxing and come home at 3 am wet and cold the last thing you wanted to do was clean the rifle. But one did even if it had been only fired once.

Nick

The Russkies experimented with smoothbore tank guns over the decades to try and prolong gun life

I presume that the tank shell imparted its own spin in flight

.

Yup, sabot rounds.

We and most of the other 'western powers' have used them for decades also. I think the bore is chrome lined.

The German Leopard 2 tank certainly does. And the Americans use the same German gun on their much loved Abrahams tank as they did not see much point in developing their own version.

Nick

Edited By Nick_G on 19/02/2016 11:38:03

Edited By Nick_G on 19/02/2016 11:41:16

Thanks for all the replies people, all are correct in their own way.

It was not until I calculated the short 'working life' (ie; time spent actually with a projectile moving in the bore) that I realised how brief a barrel's life actually is.

Give all that, I have been told of figures of 2-3,000 rounds for a 6mm PPC, 20,000 for a .222 and well over 100,000 for a .22 rimfire. My Anschutz M54 Mod 1411(Single shot .22 RF) was made in 1973 yet is still good enough to win competitions.

As for accuracy, I have always been keen to obtain a Whitworth (The famous engineer) with it's hexagonal bore.

I know that it's black powder, but was used very effectively in the American Civil War by the Confederates as General John Sedgwick found out the hard way **LINK**

At one of the local muzzleloader (black powder) comps we have an informal event where a gong about 1m diameter is sited about 300m away and one attempts to ring the gong from a standing position. The few people that have managed it get a special badge. I'm currently using a Hawken .45, never hit the gong but it is good fun. If one does not like cleaning rifles, don't take up black powder!

* Danny M *

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So were you asking a genuine question or setting a test.?

Nick

Nick it was a genuine observation, the results of which surprised me so I posed it as a question as brain food for the forumites. It has been interesting to see that I am not alone in my love of target shooting.

There is another thread on this Forum regarding 'which lathe and why?' and I discovered that in the U.S.of A. the preferred lathe for custom gunsmiths is the South Bend Heavy 10. It's indigenous to the U.S of A. and barrels fit through the headstock spindle (with a spider) for chamber cutting/reaming and threading type work.

I use my lathe for trimming and neck turning cartridge cases. Many of my accessories such as cartridge length gauges, wind flags and a barrel tuner have been home made. They work.

Now if one had access to this technology then all bets are off **LINK**

Maybe that one is best kept away from civilian competition use (and the bad guys).

* Danny M *

When I took an interest in NRA full-bore rifle competition back in the 1980s, the ammunition was RG Green Spot, which was the British Army's sniper round in 7.62 NATO (identical in dimensions to .308 Winchester). It wasn't as accurate as hand-loaded ammo, and the trick was to fit a Schultz & Larsen barrel that was made one thou tight. The accurate life of this barrel was reckoned to be no more than 1,500 rounds.

An old wood machinist who worked for me was fairly deaf. I asked him how it happened. He said he had been a naval gunner on the "D" day landings operating the main guns on his ship I forget how many rounds he fired but he mentioned that every 500 rounds they had to return to Portsmouth to get new barrels ,which had been prepared for a very quick turn round. He said that after 500 rounds they could not hit a single thing they aimed at & felt that they were firing round corners

Edited By Sam Longley 1 on 20/02/2016 06:44:53