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ovenpaa wrote:

R.G.C wrote:Pertinent question, difficult reply.

I do not think the question should be addressed to aussies, as there is no proofing procedure, nor norms on the subject in their country.

There is two lists of calmibres:
-SAAMI (Society of Arms and Ammunition Makers Industry), USA Industry association who is what its name says and who establish recommendations, not rules.. I believe entering a caliber in the SAAMI list is not very much of a problem. Their measurements are Imperial
-CIP (Commission Internationale Permanente pour l’Epreuve des Armes a Feu et des Munitions) (Sorry, the official CIP language is french!!).

<Snip>

Robert, thank you for reply, I have learnt something. It does however lead me onto another question. Obviously the test rounds are fired and the action and barrel inspected along with the fired cases and assuming there are no signs of damage everything is proof stamped, however how do they tell the pressure that it has been tested to, or do they not look for the pressure so much as signs of significant over pressure such as cratering, hard bolt lift and then *assume* based on the barrel and action manufacturers and previous experience that the new cartridge is safe to use?

Ovenpaa,
Have a raad at:
http://en.wikipedia.org/wiki/Commission ... Portatives

Proof ammunition is tested separately in pressure test guns and designed such as the peak pressure (the 25% over the listed pressure for the calibre) is intended to happen at as near as possible to the chamber. In other words, they are quite fast burning powders for the calibre.

Of course, those rounds specification are established in advance, from firing in test barrels who can record the Piezo pressure. There is no guarantee that the same pressure is developed in the gun submitted to the proof (Although that with the tight chambers, long barrels and also tightbores of our match rifles, pressures developed on testing are probably higher than the 25% in prof evelopped in shrt standard sized proof barrels…)

As the protocole digest says (I have it in full somewhere here), no care is taken about the cycling or the condition of the fired cases. This is not the purpose of the proof.

Each time I went to proof house for a proof, I recovered the empty cases, as they gave precious indications as to the chamber dimensions, etc, etc. I do presume that the relatively fast burning powders does not show the same evident signs of pressure that slower burning powders could give?.

The ‘special proofing” using ammunition heated at 80° (I thnk I rememeber ths was the temerature) for 2 hours gives certainly at least 50% more instant pressure and, when using this method, signs of pressure on the cases are more evident… I only saw this process once, and dod not inspected the xases..

At the old St Etirnne proofhouse, there was a ‘museum of horros’ of firearms having not resisted to the test. I remember particularily a rifle whose barrel was split in 4 long strips just like the dowels of a beer barrel. The 4 segments were at a diameter of at least 200mm at the centre, and the barrel was kept together at receiver level …and by the barrel band at front, believe it or not… This happened some 14 years ago. I do not know what happened from the old collections when they moved in their new premises?.
R.G.C

Back to the subject....my 260 INCH rifle now has a third barrel in 6BR chambered and ready to shoot, and also a new much longer stock to get it working properly. Will post pictures when it is finished.

Oops! Sorry Rod. This forum seems to be very good at thread hijacks, conversations just wander off #

Looking forward to the pictures.

Shot the 260 Nett on Tuesday.

I only took six rounds as I knew I would be thoroughly cleaning and de-coppering between each shot. It was very misty and we just got an hour of visibility.

Pre-loaded with VitN560 in one grain increments and got up to 2945fps with no pressure signs - with a 139gn Scenar - which is about what the standard 260 Rem. will do, so hopefully more to come.

I'll take all the loading gear up tomorrow and see what she'll do with a few different powders.

Cheers
Vince

Robert,

The CIP test is only 25% over recommended maximum, is that all? I should try this in the INCH and see what it will take to destroy one. The barrel being the weak point in all cases.

What is your preference for barrels Rod? Taking quality, ease of machining, availability and cost into consideration?

woody_rod wrote:Robert,

The CIP test is only 25% over recommended maximum, is that all? I should try this in the INCH and see what it will take to destroy one. The barrel being the weak point in all cases.

Rod,

Reply directly, for not being accused of thread hijacking.

R.G.C

ovenpaa wrote:What is your preference for barrels Rod? Taking quality, ease of machining, availability and cost into consideration?

Hello,

Firstly, Robert, I think it is ok to answer this question in the forum.

Well, to be specific, I have rebarrelled my own or others' rifles using the following brands in no particular order: MAB (from Total Solutions Engineering QLD Australia), Kreiger, Archer, Border (yes I know they are the same maker), Lawton, Tru Flite and Pac Nor.

Quality is a pretty subjective idea with barrels. if it is accuracy, the best I have seen are the MAB and Pac Nor, but there are probably other reasons for this. The best group ever shot on a range was with an MAB in our rifles, 5 shots inside 15mm (almost touching) at 300 yards in a 223 Rem and AMAX bullets. The best performing rifle overall is one of our young guys shooting in the state under 25 team, and now vying for the National Team using a Pac Nor, which is simply outstanding. I have seen some really sub standard barrels from two of the names in that list.

I am using a Lawton in 308 Win, and is starting to really come good lately. The inside finish is very nice, and is the only 6 groove barrel I have fitted to date. I got a 6th overall in the last competition I entered with it, which is the best I have done yet.

The MAB's seem to be a little more consistent in bore size over say the Pac Nor, probably due to the difference between cut and button rifling.

Have not fitted many Tru Flites or Lawtons, but other people like them. I know the AU team has used Tru Flites in the past, so they must be ok. The guy that imports the Lawtons is a very good shooter with these barrels. Performance is hard to argue with.

Machining is more in my line of understanding. Pac Nor is by far the best to machine, but also the softest (the same thing mostly). MAB being the hardest to machine, but gives a good finish. The others somewhere in between. The MAB is the only one I see that generates a long chip from the chamber reamer, never with the Pac Nor, or any of the others I have done.

Availability here in AU is for us by far the Pac Nor, then the MAB, then all others. The local Lawton supplier is pretty good though, so if needed we can usually get one of those straight away. Any of the other brand names can be very hard to get at times, with some past issues with importers and restrictions from the manufacturers of barrels placed on the importers. As we very rarely deal with importers or resellers, it is not often we have to put up with this rubbish.

My personal opinion on barrels with "names" is that they are probably 20-30% overpriced. Seeing as we can retail a barrel from Pac Nor for less than the wholesale price of most other barrels, the idea of value is clearly with Pac Nor. We have no commercial ties with this maker.

I have no pesonal or business interest in any barrel maker. I really just look at the scoreboard to tell me what works and what doesn't. My own rifles use MAB, Pac Nor and Lawton barrels, so I cannot be seen as having a preference. I can never be convinced about a brand if they are not winning.

The newest version of the INCH rifle of mine. Currently wearing a Lawton 308 barrel. The stock looks a bit better in the flesh, is made from solid Tasmanian Oak.

Is it quite long, and feels a lot better balanced than the previous one.

The previous two posts are mine.