6.5 mm SAUM. Too good to be true?
 

I stumbled on the 6.5 mm SAUM as engineered by George Gardner and built by GAP precision. There is a very informative article on the Snipers Hide about it.
http://forum.snipershide.com/snipers...-6-5-saum.html
It's a necked down 7mm saum / 300 saum.
But with H1000 they are getting +3000 round barrel life. And it's pretty fast! It's the low pressure they are able to pull off. Similar pressures as a .308 !
Really easy recoil with the 6.5 mm.
It's winning a bunch of competitions right now.
Headstones brass will be available this summer /fall.
I'm researching for my first build and this seems like the perfect hunting gun while still being able to shoot it at the range all day. When factory brass becomes available I think it will be very popular. I encourage you to read the article before commenting. It's long, but worth it.

There is something that needs to be understood when wildcats like this come up.
First: There is no "magic" combination of bullet and case, justr options

Second: just because a cartridge is winning doens;'t mean it's "better" what it does mean is that people ar using it. It is my firm belief ta the same people would be winning no matter what the "flavour of the month" was.
We have seen this with the 6.5WSM, 6.5WSSM, 6.5Creedmoore, and many others.

Third: this was tried as soon as te SAUM cases were availale, I was necking them down when shortmags.org was still alive and got the idea from a fella in Virginia!
launch a bullet at 3,000FPS or thereabouts and it doesn't matter too mauch what case it came out of.
I do believe it has a bit more throat life than the WSM however.

Cat

6.5 x 47L, Ron Matuzuelem and I came up with a similar plan about two years ago. Take a 300 WSM case full length resize it in a 300 SAUM to lengthen neck, then neck it to 25 caliber. (I had been playing with a 25 WSSM with a 1:8 twist barrel, shooting 135 gr bullets with some success. Had some great 1000 yd results with the 25 WSSM but was maxed out for case capacity.)

Reamer was ordered, Jury 1:8 barrel ordered, rifle was built to compete in F-Open matches and weighs 11 KG with scope. No load data for anything like this but, I've been doing this for years. Retumbo would be the choice powder for this build, because of its low heat index. Retumbo did cause some extreme pressure problems, starting loads were a bit light causing detonation but pressures smartened up as I increased charge. 58 gr of Retumbo caused .008" extractor groove expansion and soot ring around primer. At 59.5 gr high pressure indicators were gone. Found a sweet spot at 62.5 gr, accuracy was impressive, Oehler chronograph showed 3150 fps with 135 gr bullets.

Hope to have this rifle ready to compete with at the Western F-class finals in Chilliwack early summer.

Dale your wildcat load development process is interesting.

You kept increasing the charge after a low charge detonation (ok, I get that bit). Then increased it again after .008" case head expansion and the primer soot ring....till the pressure indicators went away and accuracy increased.

I don't imagine this approach is applicable to developing book loads?

Starting load was 58 gr and that's where the .008" extractor groove expansion and primer soot happened. 58.5 not as bad, 59.0 improving 59.5 no extractor groove expansion no cartridge scuff marks from bolt-face. Retumbo charges at less than 90% full should not be attempted.

Calls to Hodgdon's "tech line" could not or would not verify my findings with Retumbo.

I have seen the same kind of pressure spike issues with mild book loads in 7saum. Add powder and they smarten up.

agreed.i still think the 6.5x47 lapua does all the 6.5 cal is capable of.When going long you need heavier projectiles with higher bc to be competitive nowadays. the 7 saum shooting the 180 grain bergers and the 30 saum shooting the 200 plus grainers for distances past 700m seems to be the trend of late.

I would certainly be interested in your light load pressure spikes, powder, cartridge, bullet weight and primer used? The powder pedlars tech help lines aren't a lot of help when out of bounds loads are pursued. Post or PM.

It was in a friends rifle i believe it was using 7208 ssc 139g hornady sst, rem mag primers. he was using one of the lower weight charge loads in the hornady book and having some scary looking primers and sticky bolt issues, tried the max book load and they went away.

Sometimes I think load manual data doesn't take cold weather into account. What might be a great starting load at plus twenty might show detonation signs at zero degrees.

My Retumbo experience was at minus five degrees, using F215M primers.

I have seen the primer and soot with light loads
On a few rifles in the past but the WSM and WSSM cases come up mind
Some of the light loads I had with the 30/30 would back the primers out a well until I upped the powder more
Cat

Primers backed out is a sign of low pressure. Primer is developing more pressure than powder charge and on firing primer will drive cartridge deeper into chamber. Bolt face supports primer and case is blown forward. Getting rid of live primers in empty cases by firing in chamber will back out primers too, and will set shoulders back slightly.

wow!!!

R.

I realize that , just thought it was understood by all that backed out primers with light loads would be because of underpressure.
Cat