Barrel wear in a .22 centrefire

[Acm]

I’ve been wondering today about barrel life in different calibres. Why is it something like a .222 or .223 which will shoot to 3300 fps very easily is seen as being easy on barrels when something like a win mag which shoots the same sort of velocity albeit at a higher pressure and with a much bigger bullet is seen as hard on barrel. Obviously the above statement is true but why is it so?
Hoping someone with a bit more knowledge can explain it to me!

 

[Sinistral]

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[Heym SR20]

The 222 /223 don’t use a lot of powder compared to say a 300 win mag. So much less energy and thus heat involved. Most throat wear is due to very high heat burning away the steel. Less powder equals less energy and less heat.

 

[njc110381]

It pretty much comes down to the volume of powder vs the size of the hole the gasses have to be forced through. Bullet weight then adds to the amount of time that hot gas is held in there - a lighter bullet will get out of the way faster, all other things being equal.

A .45-70 uses more powder than a .22-250 but the bore is huge so the round counts are like chalk and cheese. Rounds that have a high powder to bore ratio are referred to as overbore. They're good performers but that performance comes at a cost. A lot of people never really think about it but barrels are a consumable just like powder and bullets.

 

[JTO]

I’ve been wondering today about barrel life in different calibres. Why is it something like a .222 or .223 which will shoot to 3300 fps very easily is seen as being easy on barrels when something like a win mag which shoots the same sort of velocity albeit at a higher pressure and with a much bigger bullet is seen as hard on barrel. Obviously the above statement is true but why is it so?
Hoping someone with a bit more knowledge can explain it to me!

I think it's a combination of heat and pressure.

 

[Bowland blades]

I’ve been wondering today about barrel life in different calibres. Why is it something like a .222 or .223 which will shoot to 3300 fps very easily is seen as being easy on barrels when something like a win mag which shoots the same sort of velocity albeit at a higher pressure and with a much bigger bullet is seen as hard on barrel. Obviously the above statement is true but why is it so?
Hoping someone with a bit more knowledge can explain it to me!

Barrel erosion is mainly about heat ! More powder , more heat . Shoot long strings without cool down and a barrel last less time
22 hornet burns up to 13 grains absolute case full down a 22 bore and lasts a lot longer than a 222 or 223 especially so with a 22-250 they burn more powder making more heat
A 17 hornet would last less long the bore being smaller the hot gasses being more confined
22 swift fully stacked will last less than 22-250
There is no set life, barrels vary and shot cadence matters but the majority of shooting induced damage is Hot Gases and shooting long fast strings to the barrel has no time to loose heat

 

[Acm]

Thanks guys, these are really interesting points. Recently buggered a barrel on a rifle and wondering how much of that was due to shot count.

 

[ColinBr]

Can also come down to which powder is being used.

For example RS60 is considered a barrel burner when compared to RS62, yet both perform admirable in my 6.5.

 

[Laurie]

The 'standard' method of classification is the case capacity (grains water) to bore area (square inches) ratio. This affects much more than just barrel life as it also influences powder burn rate and how 'well balanced' / 'picky' a cartridge is in loads terms.

If you take 22 centrefires, the area of a 224 bullets is 0.039 sq inches.

The .22 Hornet case has a nominal water capacity of 14.5gn, so its ratio value is 372.
222 Rem = 26.9gn = 690
223 Rem = 30.5gn (my brass and rifle chamber) = 782
The Creedmoor case holds c. 52gn in 22 form, so the 22CM wildcat = 1,333
The 308 case holds c. 54gn in 22 form, so the 22-308 wildcat = 1,385 ............. and is in effect the largest case that can be used for 22s, too large in fact and why the smaller Creedmoor case has seen considerably more use in recent years

By comparison, popular smallish 6.5s (Creedmoor, 260 Rem, 6.5X55) are in the high 900s to low 1,000 range
7mm Rem Mag which is often used to define the line that marks over-bore capacity status is 1,300 (as is 7mm WSM). Arguably, new powders have moved that a bit higher over the last 20, 30 years though.

There are other factors:

Pressure - the higher the pressure, the shorter the barrel life for any given cartridge bore/capacity ratio value. So, 30-30WCF (ratio a low 587) is also run at much lower pressure than the 300 Win Mag and has a barrel life several times higher than that of the magnum.

Powder characteristics primarily heat of explosion. Some powders are much 'hotter' or 'cooler' than the norm.

Barrel steel characteristics. The stainless grade used for match barrels is 'soft', so it wears quicker than an equivalent quality chrome-moly steel version.

Rate of fire / chamber throat and barrel temperatures. The faster the rate of fire and the hotter the back end of the barrel, the greater the erosive wear on the chamber throat and rear end of the rifled barrel. That's why belt-fed machine guns have QD barrels and in some cases Stellite or other super-hard and heat resistant coatings on the chamber and first few inches of barrel. American F-Class shooters 'string fire' while we in Canada and the UK shoot two or three on the mound, shooting in turn and overall much more slowly. So we get much better barrel life from 'hot' cartridges like 7WSM than they do. In fact 7WSM use by US Effers and Benchresters is very low indeed, also affected by their generally much higher ambient summer temperatures than ours.