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Magnum bolt face + barrel life = Free Lunch

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Is there a 6.5 or 7mm cartridge on a magnum bolt face that has a half decent barrel life say ~1500 - 2000

Or am I dreaming and you never get a free lunch

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7mmSaum could be the kindest - if you never let it get hot. Even with F Class use, I estimate it would max out at around 1000. For benchrest half it!

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FB,

 

Yes the 7mmSAUM would be about right for your 'dream'. As Vince said, do not run it too silly and the 1500+should be attainable.

 

I'm running one and have two loads, a sub HME using 175g SMK's and a 'full house' using Berger 180g Hybrids.

 

 

7%20SAUM_zps0jn6ibud.jpg

 

 

Nice cartridge, I use Norma 300 SAUM brass for the parent case but I think Norma now do 7mm SAUM

 

You can find good basic info on the 6mmBR forum here: http://www.6mmbr.com/7mm284.html

 

But the 7-08 with 162g A-Max's is not to be sneezed at and will give more milage.

 

Brgds Terry

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I have a .300WSM T3 for which I also use two loads, one sub-HME to preserve barrel-life/comply with range orders, and a full-power load for long range work.

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Have a read up on 6.5 SAUM 4S. There's a big thread about it on Sniper's Hide and I think Elwood on here has one too. Supposedly these will achieve a 2-3000 round barrel life. The secret is apparently the use of cooler, slow burning single base propellants with pressures kept at ~55k PSI and 'moderate' velocities around 3000fps with 140 grain bullets.

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My 6.5WSM didn't last any longer than my 7WSM - why should it? Same amount of powder through a smaller hole. And that was mainly F Class.

 

If you run it at 3000fps - what's the point? You'd get that from a 6.5-284 or even a 6.5x55.

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Better barrel life than the 6.5x284 and better velocity than the Swede. At least, that's what they are claiming!

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MV? Definitely - I was running mine at 3400fps with 139gn Scenars.

 

Barrel-life? - 'they' are deluded!

 

You burn a lot more powder in the WSM than the 6.5-284 (a good 10gn more) and shove it through the same 6.5mm hole - how can that be better for barrel-life?

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No, it's based on the smaller SAUM case, not the WSM. There are now a few 6 and 6.5mm wildcats where people are claiming extended barrel life, e.g. 6mm Competition Match, 6mm SLR and 6.5mm SAUM 4S. They all share basically the same characteristic: 3000fps with slow, cooler burning single base propellants at moderate pressure, e.g. H1000 or N160.

 

It would be easy just to dismiss it all as internet hooey, but there are enough people reporting the same results on reputable forums, to make me think that there might be something in it.

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The alleged secret of the 6.5 Saum is keeping the pressure below 55,000 psi by using slow cool burning powders in a case that helps achieve the desired results. The other thing to remember is that the 6.5 Saum was primarily designed as a short action light weight hunting rifle with good knock down power.

My head tells me to agree with Vince, more velocity and smaller hole equals less barrel life, but then I have to ask myself what does GAP have to gain by hood winking a few hundred customers? The answer is absolutely nothing except a bad reputation and a whole lot of Hornady 6.5 Saum brass which will not sell, make your own mind up.

I bore scoped my barrel at 600 rounds and it looked like a 7/WSM after the same amount, and if I was abetting man I would have said that it wouldn't have lasted the distance, but then again barrels are funny things and they don't always give up when they are supposed to. Last years F open League winner is currently using a 7/WSM that has 1600 plus rounds and it's a laser, but it shouldn't be!

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No, it's based on the smaller SAUM case, not the WSM. There are now a few 6 and 6.5mm wildcats where people are claiming extended barrel life, e.g. 6mm Competition Match, 6mm SLR and 6.5mm SAUM 4S. They all share basically the same characteristic: 3000fps with slow, cooler burning single base propellants at moderate pressure, e.g. H1000 or N160.

 

It would be easy just to dismiss it all as internet hooey, but there are enough people reporting the same results on reputable forums, to make me think that there might be something in it.

I know we are talking about the SAUM case but - if you shoot a 6.5WSM you probably don't fill the case but you can with a SAUM - hence my comment.

 

This barrel-life thing - how do shooters assess it? If you have a borescope you will know. If you shoot long range benchrest, you will know. If you shoot F Class, it may not be so obvious. For a start, how many shooters really record how many rounds they put down their barrel? I shoot an F Class comp. every two weeks at my home club but, that's only 500 rounds per year.

 

The 6.5WSM or 6.5SAUM are killer long-range rounds - so why don't more shoot these cartridges? Barrel-life that's why.

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I,m just building a 6.5 SAUM for a guy. I have two Bartlien,s in stock for him. The plan is to change the barrel when the first is toast.He,s going to keep an accurate round count.

 

I,ve read the story from George Gardiner on the case and his documented 3000 round too.

 

It will be interesting to put it to the test. The chamber will be the 6.5 GAP saum.

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The alleged secret of the 6.5 Saum is keeping the pressure below 55,000 psi by using slow cool burning powders in a case that helps achieve the desired results. The other thing to remember is that the 6.5 Saum was primarily designed as a short action light weight hunting rifle with good knock down power.

 

 

 

An interesting issue. I'd similar thoughts on 6.5-284, Run it at 55,000 psi or thereabouts with N165. QuickLOAD says that a 54gn or so would be a little under this figure, see a near 100% case fill, 100% charge burn and 2,989 fps for the 142gn SMK from a 30-inch barrel.

 

Move to the SAUM and it takes around 4gn more N165 to get to just below 55,000 psi but that increases MV to 3,026 fps. 1gn less powder matches the 6.5-284 velocity but reduces PMax by a couple or three thousand psi, almost 100% charge burn. For equivalent performance, the SAUM runs at lower pressures but still puts more powder = more heat down the same size 6.5 calibre bore.

 

On the face of it, depending on what action and bolt face you have sitting around waiting on a new barrel to be fitted, either option would work pretty equally well (or badly if that's how it turns out). 3,000 rounds life though - I really find that hard to believe.

 

FWIW, I briefly ran a Bartlein 5R 30-incher on a Savage 12 F-Class rig in 6.5X55mm (the factory Savage barrel in 6.5-284 was a mediocre one) and ran somewhere around 48gn N165 with 140s. The Berger 140gn LR BT turned out to be a fantastic performer in this set up at ~2,850 fps, but I needed the PTA action desperately for an FTR rifle and the rifle was split up after a very short time in this chambering. The barrel will go back on that action at a future time. Although QuickLOAD says this setup runs at 52,000 odd psi, I'd consider myself lucky if it is still giving F-Class precision at the 3,000 rounds mark - but will eventually find out.

 

In the meantime, it'll be interesting to see how Baldie's customer makes out with his 6.5 GAP SAUM.

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I,m just building a 6.5 SAUM for a guy. I have two Bartlien,s in stock for him. The plan is to change the barrel when the first is toast.He,s going to keep an accurate round count.

 

I,ve read the story from George Gardiner on the case and his documented 3000 round too.

 

It will be interesting to put it to the test. The chamber will be the 6.5 GAP saum.

 

Dave, did you ever get a round count on that barrel?

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He hasn't killed it yet !

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He hasn't killed it yet !

Sounds promising!

 

Does he use it in the field or on paper?

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He likes blowing things up at long range.

 

Probably the most anal shooter i've ever met, money is no object when it comes to his guns or his reloading gear, and he's a very good shot.

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