Barrel material - Chrome Moly or Stainless - preferences please

[VarmLR]

18 hours ago, bradders said:

Can anyone see the irony of worrying about a barrel rusting on a forum that's obsessed with cleaning? 

Any rust spots would be summarily dealt with quicker than you could say "Martensitic" bradders!  

[meles meles]

As a small aside, we really feel we ought to defend Big Al. We exchanged a few pms, very pleasantly. The public post Big Al referred to was made before we read his pm and so was a little out of synch. If there was a fault it was on our part, not his. We certainly don't feel 'sniped' at ! His messages to us were friendly and informative. If we meet him in person we'd be happy to shake paws and scoff mince pies! He's done no wrong in our eyes.

[Big Al]

1 hour ago, meles meles said:

As a small aside, we really feel we ought to defend Big Al. We exchanged a few pms, very pleasantly. The public post Big Al referred to was made before we read his pm and so was a little out of synch. If there was a fault it was on our part, not his. We certainly don't feel 'sniped' at ! His messages to us were friendly and informative. If we meet him in person we'd be happy to shake paws and scoff mince pies! He's done no wrong in our eyes.

A very gracious reply meles meles which I appreciate.

Merry Christmas in the singular or plural, whichever fits

[ejg223]

I would just about always prefer a stainless barrel. The only part of a rifle that one really wants to protect from corrosion... has no corrosion protection, the bore. I have one LW non stainless barrel. This barrel produces brown rusty patches after 8hrs hunting in our wet climate. shot fired or not. Stainless barrels just don't have that problem at least by far not as strong.

edi

[meles meles]

It is possible to enhance the corrosion protection of the bore, though many are against it for a variety of reasons, most of them ill founded.

Chromium plating is widely used on military weapons, from pistols to the main armament on things like tanks and some howitzers. Properly done, it provides a useful increase in both wear resistance and resistance to erosion / corrosion during repeated, high intensity firing. The Russians and Chinese favour this approach for most of their guns, in the West it tends to be mainly done on machine guns. Many civilian shooters and smiths decry the practice, claiming it reduces accuracy. It can do, if not correctly performed, but if properly applied chromium plating is a definite benefit. 

The current state of the art for high end precision rifles (military at the moment, not civil) is a either a  chemically or physically deposited (CVD / PVD) diamond like coating or a tantalum plating. Both significantly improve wear, temperature and corrosion resistance.

[ejg223]

My understanding is that the main reason for barrel wear is "fire-cracking". This is a result of thermal shock behaviour. I don't believe in grain boundary wear, just by looking at affected areas. I don't think mechanical wear is the main issue as we have the most wear in the area where the bullet is at the slowest speed and least energy. Also I believe we have a certain degree of chemical attack. If one wants to reduce barrel "wear" my take is we should not look at other examples of reducing mechanical wear as in piston liners, bearings  etc. The PVD coatings are mostly types of ceramics with ultra high youngs modulus and lousy thermal shock behaviour, the last material one would want. To improve thermal shock behaviour you need very good thermal conductivity, low youngs modulus combined with possibly high yield strength.  These behaviours at a range of elevated temperatures. not easy.

I and many others are quite satisfied with the life span of a hunting rifle barrel but would hate to see a barrel rust. If one has rust after a day hunting that is where I draw the line. Generally a stainless barrel will rust less.

edi

 

[Moorlander]

So if you have a rifle re barrelled in stainless is there a way of bluing it to the same high quality sheen of steel barrels ? or would it have to be a cerocote job? 

[bradders]

If you take your rifle out in damp condition and don't treat it afterwards and it rusts, you can't blame the barrel material for your own neglect.

More shotguns with steel barrels are shot weekly than rifles, and I'd dare say in more inclement weather, yet I don't hear game shooters calling for stainless barrels on their 12 bores

[ejg223]

Bradders most shotgun barrels are chromed inside now. Outside blued which helps a bit. Shotgun you also don't mind a bit of oil in the barrel.

My LW barrel is rusted when I come home from hunting and put a patch through it, that is where i draw the line. Don't have the issues with my foxing rifles as firstly outings are shorter and secondly mostly in dry conditions. Hunting deer on our west coast in the hills is a different story, plenty rain and damp. Home to home 12hrs. Therefore I prefer stainless barrels. They even work in the dry....

edi

[meles meles]

1 hour ago, ejg223 said:

My understanding is that the main reason for barrel wear is "fire-cracking". This is a result of thermal shock behaviour. I don't believe in grain boundary wear, just by looking at affected areas. I don't think mechanical wear is the main issue as we have the most wear in the area where the bullet is at the slowest speed and least energy. Also I believe we have a certain degree of chemical attack. If one wants to reduce barrel "wear" my take is we should not look at other examples of reducing mechanical wear as in piston liners, bearings  etc. The PVD coatings are mostly types of ceramics with ultra high youngs modulus and lousy thermal shock behaviour, the last material one would want. To improve thermal shock behaviour you need very good thermal conductivity, low youngs modulus combined with possibly high yield strength.  These behaviours at a range of elevated temperatures. not easy.

I and many others are quite satisfied with the life span of a hunting rifle barrel but would hate to see a barrel rust. If one has rust after a day hunting that is where I draw the line. Generally a stainless barrel will rust less.

edi

 

It's more a matter of science and engineering allied to a dose of chemistry rather than belief.

Mechanical wear isn't due solely to the projectile, which as you grasp is moving slowly and with little energy. Trapped behind the projectile is a supersonic, high pressure flamefront carrying with it a myriad particles of partially burnt propellant that scour away at the metal, attacking the weaker areas - which happen to be the grain boundaries. The CVD and DVD coatings used in precision weaponry are quite unlike those used in engines (google is your friend).

However, given that civilian shooters don't yet appreciate chromium treatments I suspect that the technology won't cascade down into the civil shooting arena for decades to come. Look at the lag involved with stainless steels:  Harry Brearley developed them in 1913 in the quest for better guns for the RN's dreadnoughts. 104 years later we're still arguing if they are useful or not.

 

[ejg223]

Meles, I don't need google, we did enough ceramic coatings at uni. Our class also proved that several of them just did not hold up to their promise. Apart from that I developed advanced ceramics for over 20 years partially with the thermal shock behaviour in mind and hold a few patents. This was not firearms related. I am not interested in ferrous metals and did not do much in that direction.

edi

[Moorlander]

Heres something for you to all digest tomorrow afternoon  

Gun Barrels.pdf

[Laurie]

Have a look at the copy of the two pages from an old 'American Rifleman' (the US NRA magazine) on bullet diameter effects on barrel life and precision (group sizes) using the 7.62X54R with loads just under 40,000 psi. The barrel life is stupendous! (14,000 rounds before groups start to enlarge and a total usable life of 23,000 rounds.)

http://forum.accurateshooter.com/threads/243-barrel-life.3934900/page-2

(Scroll down to  Post #38 with the embedded pages)

The Gun Pimp and I discussed this afterwards. I'd ascribed most of the barrel longevity to low pressure / heat effects and presumably a cool burning propellant, but Vince points out how hard a good chrome moly barrel is too and doubts that our modern soft 416 grade 'stainless' barrels would last anything like as long even with these loads.

[clover]

Thanks guys - lots of great info that gives sufficent argument to persuade me that Stainless is superior and the way to go.

The rifle's been just about ordered although there was some consternation over the 1:8 twist (which I'd have guessed would have pretty much been the standard on the Varmint rifles, but apparently not) so they're getting back to me in the new year to confirm a lead time..

[Moorlander]

40 minutes ago, clover said:

Thanks guys - lots of great info that gives sufficent argument to persuade me that Stainless is superior and the way to go.

The rifle's been just about ordered although there was some consternation over the 1:8 twist (which I'd have guessed would have pretty much been the standard on the Varmint rifles, but apparently not) so they're getting back to me in the new year to confirm a lead time..

You have a choice on twist with the .223 , from the factory web site http://cdn1.tikka.fi/sites/default/files/technicalspecs_t3x_varmint_stainless_0.pdf

[GT3_richy]

If you're after a Varmint or SV you should find 1:8 and 1:12 both on the shelf easily enough, blued or stainless.

The bigger issue is if you want more than a 20" barrel. No one stocks the 24" barrels in the UK, they're special order and usually a 6 month lead time...

[VarmLR]

You can get lucky...I did.  My 308 was a varmint profile in 24 inch S/S and no waiting.  It pays to phone around...GMK do now import a lot of 24 inch T3s into the UK every year now.

The option is to buy a used rifle for the action and rebarrel with something like a LW in LW50 stainless.  I had one of mine done with a 26 inch match contour LW LW50 barrel which was then blued (ok..blacked).

[GT3_richy]

2 hours ago, VarmLR said:

You can get lucky...I did.  My 308 was a varmint profile in 24 inch S/S and no waiting.  It pays to phone around...GMK do now import a lot of 24 inch T3s into the UK every year now.

I didn't! 

Spoke to GMK who said 'special order', and rang I don't know how many shops for both .204 (expected this to be a wait as I doubt its that popular compared to ->) and latterly .223. I'd been scouring GT and GS for sometime beforehand too. You do seem to see more variety available in .308 however, see the odd TAC/CTR with longer barrels in particular.

Other 'issue' with the 600mm barrels is they arent cut for a mod from the factory. I think I'd go for your option #2 - get a donor and have what you want put onto it, probably for not much more cash.

[snakeman]

42 minutes ago, GT3_richy said:

Other 'issue' with the 600mm barrels is they arent cut for a mod from the factory. I think I'd go for your option #2 - get a donor and have what you want put onto it, probably for not much more cash.

Not an issue

If you go down the ordering route you can request the 24" barrel to be factory threaded if you wish. ...All of the options will be available to you if you place an order. I'd also strongly recommend the single-set trigger, again only available as an option... Love 'em or hate 'em it's the sweetest set-trigger you'll pull and, will be huge bonus if you're shooting for groups... IMO significantly superior to my CZ 527 set-trigger

As a gauge for you, from placing my order to the rifle delivered, took 7½ months ...(although I have known others to be 5 months)

ATB

[meles meles]

Ah, still quicker than ordering a 'London Best' shotgun then....

[Big Al]

15 hours ago, GT3_richy said:

get a donor and have what you want put onto it, probably for not much more cash.

Theres a lot to be said for going that route but then again coming from me it would hardly be seen as independent advice

[VarmLR]

I think it's fair comment though Al, and most would agree with you.  

UKV has more than its fair share of highly respected and competent smiths who I, for one, would trust to do a great job too.  

[clover]

On 24/12/2017 at 5:48 PM, Moorlander said:

You have a choice on twist with the .223 , from the factory web site http://cdn1.tikka.fi/sites/default/files/technicalspecs_t3x_varmint_stainless_0.pdf

Yes, thanks - I'm aware of that. The issue being that the first time I enquired about the 1:8 twist it was implied that the lead time would be fairly short as it's a common option (rather than a special order) which I figured would be the case since I'd guess this would be a popular choice in the heavier barrel profiles. Upon placing the order however, air was sucked through teeth and "special order" was mentioned.. 

On 24/12/2017 at 11:03 PM, GT3_richy said:

If you're after a Varmint or SV you should find 1:8 and 1:12 both on the shelf easily enough, blued or stainless.

The bigger issue is if you want more than a 20" barrel. No one stocks the 24" barrels in the UK, they're special order and usually a 6 month lead time...

As above, this is what I expected regarding the twist rate and what I was told when first enquiring. 

I agree about the barrel length.. my gut tells me to go longer on account of improved ballistics, however I've been told the same re. the availability of the 24" variants. I've been pretty much sold on the 20" version since it's threaded and should be quicker to get (for reasons I won't go into I have a somewhat limited window to acquire the rifle). 

That said if the spec 20" 1:8 twist turns out to be a special order, I might just spec at threaded 24" barrel if already paying the time penalty. 

 

 

[Conorj]

Sorry to jump on this thread, wud I be correct in saying the t3 tactical is a chrome moly barrel? Is the tactical version going to be any more accurate than the super varmint/varmint model in the same 1:8 twist and 20 inch barrel?

[VarmLR]

The Tac A1 benefits from the solid chassis bedded design which in itself is meant to raise it in the accuracy stakes.  Back in the real world, I have seen some astonishingly good groups at 200 yards from a standard (older model) T3 Tikka (non varmint).  All T3's seem to be great shooters.   It's not a bench rest rifle and was never intended as one but they are very accurate.   Shame though that they couldn't take the trouble to finish the muzzle thread properly for the Tac A1.  They are not cut up to the barrel shoulder, but stop 4mm or so short (being designed, as Tikka conveyed back to me via GMK for their muzzle break and threaded for that) so they've essentially left half a job on the threads which may or may not result in moderators being properly concentric when tightened up to the mini shoulder at the thread end.  This is unforgivable on a £1600 rifle.  Mine was machined such that the moderator wasn't quite concentric enough resulting in a written-off £230 moderator.