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Barrrel life


KABOOM

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I've had 223 barrels last me 14K rounds and still be competitive at PR and others need changing at 3000 rounds. I know a few top shooters in the States who will not go to the Nationals at Camp Perry with a barrel that's shot over 1000.

I find as soon as I think I can shoot better than the barrel it's time to change. Usually this is between 3000 and 6000 for .223.

My last barrel had just done about 5500 and I hadn't realised how bad it was - I had taken 2½ years off competitive shooting for health reasons and started this season of CSR thinking that although the scores were passable the errors were just me being out or practice. But I changed the barrel over the winter break and was surprised at the difference. I'm not as rusty as I first thought! However the virus shut-down has halted the practice I was hoping to get before the Imperial that would prove it.

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There are so many factors involved in this, it’s an almost impossible question to answer.

Barrel material, method of manufacture (eg cut, button, hammer forging), calibre, powder used, charge weight, pressure generated, heat generated, long strings of fire (hot barrel), slow strings of fire (cool barrel), cleaning solvents, method of cleaning are some of the factors that will determine barrel life.

In terms of accuracy from barrel life, that’s rather subjective too. A comp shooter may say only 2000-3000 rounds of x-calibre because it’s no longer consistently shooting 0.25MOA. Whereas a hunter with same barrel and calibre might say 5000+ rounds because they’re still shooting sub MOA.

Good blog, the first in a new series, on the matter;

https://precisionrifleblog.com/2020/03/24/how-fast-does-a-barrel-wear/

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3 hours ago, Catch-22 said:

There are so many factors involved in this, it’s an almost impossible question to answer.

Barrel material, method of manufacture (eg cut, button, hammer forging), calibre, powder used, charge weight, pressure generated, heat generated, long strings of fire (hot barrel), slow strings of fire (cool barrel), cleaning solvents, method of cleaning are some of the factors that will determine barrel life.

In terms of accuracy from barrel life, that’s rather subjective too. A comp shooter may say only 2000-3000 rounds of x-calibre because it’s no longer consistently shooting 0.25MOA. Whereas a hunter with same barrel and calibre might say 5000+ rounds because they’re still shooting sub MOA.

Good blog, the first in a new series, on the matter;

https://precisionrifleblog.com/2020/03/24/how-fast-does-a-barrel-wear/

Perfect reply! we tend to all think in the same way. To date my CZ550 22-250 has 4400 rnds down the tube, been hot enough to brand cattle and still does .50 5 shot groups, yes it slowed 150 fps. When I see keyholes its new barrel time. My other 22-250 was built in 1951 purchased used and zero idea of round count .25 is normal grouping for this one, 30 inch barrel means 3850 fps with a 50grn Nosler Ballistic tip over CFE ,223, Lapua brass, Federal 210M primers.

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When I was shooting F class competitively I would recon on 8-900 rounds on a 7mm WSM or similar 1500 on. Shehane 

Deer work/ range / practice  - sub 1400 accurate rounds on 6.5/284 (over the years had four barrels on one action ) 

2000 to 3000  on 6.5/47  (three barrels on two actions  ) depending on how the barrel is looked after 

25-06 sub 1500

Ive yet to shoot out a 308 barrel 

 

 

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My Orsis .308 barrel has done 2,350 rounds now.  Still almost as good as new.  I load 155 Lapua Scenar with N140 at around 2,730fps av.

I shoot on a gallery range so the shot-rate is low and barrel heating is therefor also low.

I clean after every shoot (usually 30 to 40 rounds) using Wipe Out and a nylon brush.  Very infrequently copper remover used.  I have a Hawkeye bore scope and everything looks fine.  The throat has next to no erosion based on my gauge figures.  The barrel has cut rifling at 1:11

I think those Russkies know how to make good steel!

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On 3/27/2020 at 12:24 PM, The Gun Pimp said:

Well, I agree with about 800 rounds from a 7mmWSM for F Class shooting but for benchrest you can drop that to about 450.

308?  I couldn't believe my first FTR barrel was goosed after 1100 rounds - I'll not be using Vit N540 again.......

I used a couple of 3.5kg tubs of N540 in my 308 and it trashed my barrel.

When I went back to RS40 and 155gr scenars I chased the rifling to find the bullets bolt tail was nearly out of the case it had eroded so bad 😂

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I bought an RPA 7mm-08 with an Archer barrel nearly 17 years ago. I never load to the maximum, nor do I use double base powders. I know it's limitations and it's a solid 800m rifle giving comfortably sub-MOA five round groups. 

Its had nearly 5K through it so far. 

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1
17 hours ago, simgre said:

I bought an RPA 7mm-08 with an Archer barrel nearly 17 years ago. I never load to the maximum, nor do I use double base powders. I know it's limitations and it's a solid 800m rifle giving comfortably sub-MOA five round groups. 

Its had nearly 5K through it so far. 

I'm sorry to say 'simgre', that RS40 contains both nitroglycerine (NG) and nitrocellulose (NC), so you are using a double based propellant. According to the propellant's MSDS (Material Safety Data Sheet), it contains these energetic components; 82% NC and 12% NG. The other ingredients stabilisers, coatings, etc.. So RS40 has slightly less (4%) NG than the dreaded (on this forum) RS60. See images below.

1506422672_RS40andRS60.thumb.png.3ccc7ea14ac9651f613ccb97ee40b87f.png

441515786_RS40MSDS.thumb.png.b5f5eb49823771bbab4a9383d6e87a64.png

RS40 is one of the extruded impregnated (EI) developed by Nitrochemie Wimmis and sold commercially by the entity known as Reload Swiss. You'd have to move to something else if you want to get away from NG-containing propellants.

For note, just because something contains only NC doesn't mean it isn't erosive. The flame temperature (not to be confused with the heat of explosion) is the primary erosive factor in guns. The flame temperature of NC and hence its erosivity is dependant on NC's degree of nitration. Not all NC is the same.

I have a mountain, well rather a lot, of data on gun erosion should anyone want some more information or recommendations of stuff to read.

For note, it seems I can't link to the right quote, or even a quote with this in? Too early in the morning. I blame CV19!!!

Edited by BlueBoy69
Rubbish quote linkage!
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5 minutes ago, BlueBoy69 said:

I'm sorry to say 'simgre', that RS40 contains both nitroglycerine (NG) and nitrocellulose (NC), so you are using a double based propellant. According to the propellant's MSDS (Material Safety Data Sheet), it contains these energetic components; 82% NC and 12% NG. The other ingredients stabilisers, coatings, etc.. So RS40 has slightly less (4%) NG than the dreaded (on this forum) RS60. See images below.

1506422672_RS40andRS60.thumb.png.3ccc7ea14ac9651f613ccb97ee40b87f.png

441515786_RS40MSDS.thumb.png.b5f5eb49823771bbab4a9383d6e87a64.png

RS40 is one of the extruded impregnated (EI) developed by Nitrochemie Wimmis and sold commercially by the entity known as Reload Swiss. You'd have to move to something else if you want to get away from NG-containing propellants.

For note, just because something contains only NC doesn't mean it isn't erosive. The flame temperature (not to be confused with the heat of explosion) is the primary erosive factor in guns. The flame temperature of NC and hence its erosivity is dependant on NC's degree of nitration. Not all NC is the same.

I have a mountain, well rather a lot, of data on gun erosion should anyone want some more information or recommendations of stuff to read.

Blueboy 69 should be part of any serious reloaders tool kit .

cheers for your input 👍👍

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Practical competition / long range use:

338 LM: +/- 1200 rounds if you don’t go mad with pressure/ velocity. VV N 170 / 165 single based powders. I don’t believe manufacturers blurb with double based “cool burning” powders, eg n570, n565 - yes a little less pressure spike but for much longer burn time. No free lunch.

308: +/- 5000 rounds

More cryptic barrel life is about 2 seconds. 

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Thinking aloud

 

what is the barrel life on mil automatics (7.62 and 338 ) 

Rotary multi barrel systems deliver several thousand rounds per minute and are capable of sustained use 

Is there any use of different material or coating which prevents premature wear ?

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Andy, I have a belt-fed cz 59 semi in 7.62x54. After 4k rounds of mil surp best China crap ammunition ( corrosive primers) the first 2” of rifling  is missing. Usually use a 50 round belt with it after which the barrel will remove your fingerprints if you touch it. Barrel is hard chromed lined or was (so are cz 58s). Replacement barrels are cheap.

Hard Chrome seems the cheapest way to extend barrel life or nitride maybe. Accuracy becomes an issue though keeping chrome consistent- if memory serves at one point Tanner ( Swiss) once offered chrome lined match barrels for their rifles.

 

 

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5 hours ago, BlueBoy69 said:

I'm sorry to say 'simgre', that RS40 contains both nitroglycerine (NG) and nitrocellulose (NC), so you are


I’m sorry to say BlueBoy69, you’re confusing me with a previous post of someone else. 
 

I don’t use RS40, never even tried Reload Swiss powders, and it remains I’ve never used a double based powder in my RPA...

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Using N140 and now RS50 in my 308 I have just under several thousand rounds down it and checking the lands it's still as good as new...they've moved back fractionally but the bore looks great.

The 223 has had some hot loads through it, mostly N133 and RS50 and on my new barrel I'm up to around 1200 rounds on that with slightly more throat erosion than the .308.  I'll dig my notes out but I think the throat had gone back about 5 thou.  I may load back a bit as I want at least another 5,000 rounds from that barrel.

6.5CM...moderate loads for SRP brass using RS62 and no discernible wear after about 700 rounds through that.  Hopeful for at least 4000  rounds out of that barrel as long as I keep loads moderate.

I won't touch any double base powder with a long bargepole as I don't shoot comp and can't justify a new barrel every season at £750 a pop!

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  • 2 weeks later...
On 4/5/2020 at 10:06 AM, brown dog said:

Blinkingly, re-read this paragraph a couple of times...  can't get my head around a 'single base' powder with both NC and NG. I need more coffee.20200405_095700.thumb.png.971f10653ec9a90a6ce4825d67d839df.png

It's because it's a single base powder that has NG impregnated (diffused) into it. It's not made as a double base propellant where the NG is used as the propellant's plasticiser and that also forms part of the energetic components. It's easier is I post an image of a propellant grain that has been impregnated with NG.

image.png.34218de51701feb373e108964548e155.png

So the artificially yellow (gold) coloured areas are where the NG has diffused into the multi-perforated (7-perforation) single base grain. The RS propellants we can buy, as far as I am aware, only have one perforation (i.e. they are tubular).

But yes, ultimately, this makes it a 'type' of double-base propellant on par with an NG content that is similar to that of ball (or flattened ball) propellants.

image.thumb.png.d82fbfde996f23a8bb469acbc0829533.png

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