6.5 gap saum

[mongoosesnipe]

But the Grendel is a 32 grain case running low pressure and medium velocity which is a recipie for a long barrel life similarly the 6.5 swede tends to do well barrel wise with low pressures and medium velocities

[bwaites]

But the Grendel is a 32 grain case running low pressure and medium velocity which is a recipie for a long barrel life similarly the 6.5 swede tends to do well barrel wise with low pressures and medium velocities

In theory, though, this really is a relatively low pressure round, at 55-58,000, so I would expect better life. I just couldn't figure that velocity at that pressure! I can't get much better than 2600-2700 out of my Grendel 28" with a hot load, and I'm thinking I'm in that same pressure area. (Not on purpose, but in developing loads). I can't run a powder as slow as H1000 and fill the case, though. CFE might get me closer, so I really need to start working with it. Interestingly, my most accurate Grendel loads ever were with BLC2, which is exactly one step above CFE on the burn rate chart. I really need to explore both in the long barrel Grendel.

My first couple Grendel barrels have gone well past 5000 rounds with great accuracy. One started to fade a bit at 5500 or so, and I didn't feel any real need to replace it until after 6000, when I still had a couple loads that were sub-MOA. It had regularly shot .25 inch groups, though, so that felt like a terrible loss. It would still have been a fine hunting barrel even then!

[adamjp]

On the 6mmBR site a few years back a gent posted a formula for considering how 'hot' a cartridge was. In effect it was the case capacity in grains of H2O divided by the bore area.

Using this a Grendel comes out at an index of 639.

A 223 is 766, 308 751 and a 300 Win Mag is 1181.

When you consider the formula (which needs to include pressure in a meaningful way), anything with an index of over 1100 is definitely into the 'low round count' zone. Anything over 1200 is into the 'barrel burner' zone.

A 6.5-284 is 1205, 264 Win Mag is 1516!

The 6.5 SAUM is 1333, just a touch behind the 7mm Rem Mag at 1326.

If you accept that a hunting 7mm Rem Mag should go for 2000 rounds @ 62000 PSI, there is no reason to dismiss a 6.5 SAUM going for 2000 @ 58000 PSI.
Overbore Index 2011.png

If you multiply the index value by the operating pressure and then divide by 100,000 to get a workable number then pressure is catered for.

[mongoosesnipe]

2000 sure but he has 4400 rounds into it and it's going strong which is phenomenal

[BluntForceTrauma]

Any pix of the 6.5 RSAUM cartridge itself? An efficient cartridge is object of beauty.

John

[LRRPF52]

[mongoosesnipe]

that cartridge looks mildly overbored...

[BluntForceTrauma]

Thanks, LR. Looks "mildly" accurate, too!

For the same reason I like the shorter Grendel case vs. the longer SPC case — i.e., allows sleeker bullets — I had always wondered why the Winchester short mags seemed to gain more popularity than the Remingtons. Anyway, seems like the longer 6.5s and the SAUM case are a match made in heaven.

John

[bwaites]

Thanks, LR. Looks "mildly" accurate, too!

For the same reason I like the shorter Grendel case vs. the longer SPC case — i.e., allows sleeker bullets — I had always wondered why the Winchester short mags seemed to gain more popularity than the Remingtons. Anyway, seems like the longer 6.5s and the SAUM case are a match made in heaven.

John

Timing, and Remingtons reputation for very poor support after cartridge introduction. Even now, I don't think that they make any RSAUM chambered rifles except on special order. Its the wildcatters that are carrying the ticket.

[adamjp]

Any pix of the 6.5 RSAUM cartridge itself? An efficient cartridge is object of beauty.

John

Does this help?6.5 Cartridges.jpg

From my personal collection of 6.5s. The only one I don't have a rifle for is the 260, although I've just bought a barrel for a Rem700 in 260, AND I've got a spare action sitting here looking for work.

[BluntForceTrauma]

Thanks, Adam, now all you need is a 6.5 Creedmoor!

John

[adamjp]

Thanks, Adam, now all you need is a 6.5 Creedmoor!

Why buy an American copy of the 6.5x47 Lapua when Lapua brass is cheaper in Australia than Hornady? Better quality too.

To be honest, that's why I've not bothered with the 260 Rem as well. It does nothing my 6.5 Lap won't do and I'm already setup to reload that for match rifles. The 6.5/06, despite being built for a purpose may well be rendered obsolete by the 6.5 SAUM. At that point I will have to decide what to do with a very nice No.1 in 6.5/06. I doubt I will have any problem selling it - I already have two offers for it and it is still a bit of a frankenrifle as I've not finished the woodwork.

[nincomp]

that cartridge looks mildly overbored...

Actually, it reminded me of my former supervisor - a fat pin-head.

[woohoo]

I've been shooting a 243 30 degree AI more or less with H1000 for several years. Barrel life is much better than when using 4350 or RE17. I built a 6.5RSAUM AR10 in 08, used it in a few comps and it shot well but I just didn't need that much cartridge or the recoil that goes along with it when the 243AI would give the same performance. Anyway, I believe the slower burning powers help increase barrel life ...not sure about 3 times as much though.

[jluck]

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Mmmmm.....Bullet porn.