370 Sako Mag (9.3x66)

Ok finally shot my Black Bear 9.3 x 66 and results for the 286gr Woodleigh PP are as follows: 62.5gr RE15 2402fps and 64.5 RE15 2464fps. Those were obtained with a Labradar at an 50m indoor range so accuracy testing will have to wait till later. Recoil as you all know is stout! But it was a lot better than the 458Lott I was also testing! The 2" less barrel length cost me about 8-16fps respectively. So bugger all!

Even though its supposed to be the same Sako 85 action the magazine box in this Black Bear appears to be shorter. In my old 85 Hunter I could load to 3.375" OAL but in this rifle I had to load to 3.355". Production variances perhaps. I was using up my old loaded ammo and just seated them a bit deeper - no issues.
 
… you need to be selective with projectiles, as many 9.3 bullets are designed for x62 velocities.
bruce.
Hello Bruce can you elaborate a bit on which projectiles are suited for the faster x64, and which once are more suited for the slower x62?

Grtz,
Keiler
 
Hello Bruce can you elaborate a bit on which projectiles are suited for the faster x64, and which once are more suited for the slower x62?

Grtz,
Keiler
Sadly Bruce passed away in early June. He is sorely missed by the AH community. I hope his family is doing well. As well as they can
 
Sad to hear about Bruce passing away. We had some good conversations regarding the 9.3mm over the years and shared loading data.

Here is my latest data I worked up for the 9.3x66.

Rifle: FN M98 Custom Safari by Safari Arms
Barrel: 24" Lothar Walther
Projectile: Nosler 9.3mm 250 grain Accubond
Case: Sako
Primer: CCI Large Rifle
Seated OAL: 3.375"
RCBS loading dies (370 Sako) and custom Lee Factory Crimp die.

67.0 grains Rx17, 2560 fps, 3639 fpe (good practice and case forming load)

70.0 grains Rx17, 2680 fps, 3988 fpe (compressed load and very accurate in my rifle. 1 1/2" five shot group at 200 yds with three holes touching!)

Once cases are fire formed, I set the sizer die .010" off the shell holder to mostly size the case, without setting the should back. This allows for easy clambering, close headspace and long case life.

All seated rounds are Lee Factory crimped.

My case forming load is either 14.5 grains of Green Dot or IMR Target with a 280 grain gas checked cast bullet by Mountain or Accurate Molds for about 1480 fps. Very mild, accurate and sets the shoulder out every time.

Though very accurate, Rx17 seems to be a bit slow with lighter bullets in this caliber, running out of space before hitting peak. I have some Viht N150 that I'll try next and see if it is more optimum for the Nosler 250 gr. Accubonds.
 
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Sad to hear about Bruce passing away. We had some good conversations regarding the 9.3mm over the years and shared loading data.

Here is my latest data I worked up for the 9.3x66.

Rifle: FN M98 Custom Safari by Safari Arms
Barrel: 24" Lothar Walther
Projectile: Nosler 9.3mm 250 grain Accubond
Case: Sako
Primer: CCI Large Rifle
Seated OAL: 3.375"
RCBS loading dies (370 Sako) and custom Lee Factory Crimp die.

67.0 grains Rx17, 2560 fps, 3639 fpe (good practice and case forming load)

70.0 grains Rx17, 2680 fps, 3988 fpe (compressed load and very accurate in my rifle. 1 1/2" five shot group at 200 yds with three holes touching!)

Once cases are fire formed, I set the sizer die .010" off the shell holder to mostly size the case, without setting the should back. This allows for easy clambering, close headspace and long case life.

All seated rounds are Lee Factory crimped.

My case forming load is either 14.5 grains of Green Dot or IMR Target with a 280 grain gas checked cast bullet by Mountain or Accurate Molds for about 1480 fps. Very mild, accurate and sets the shoulder out every time.

Though very accurate, Rx17 seems to be a bit slow with lighter bullets in this caliber, running out of space before hitting peak. I have some Viht N150 that I'll try next and see if it is more optimum for the Nosler 250 gr. Accubonds.
@fsrmg1
The 35 whelen with 250 grainers and 64 grains of CFE223 is getting 2,700fps so I would have thought the 9 3x66 would have done better
Bob
 
@fsrmg1
The 35 whelen with 250 grainers and 64 grains of CFE223 is getting 2,700fps so I would have thought the 9 3x66 would have done better
Bob
Interesting, is that measured velocity or guesstimated? What sort of pressure you running at? I bet it is pretty warm... I couldn't find any data for the Whelen using that powder, so would be cautious on the side of safety.

The only powders I could get my hands on over here before the shelves ran completely try was Rx17 and N150, so that is what I'm limited to right now. Both are bulky powders on the slower side for this cartridge, but are mild mannered and work well enough to get the job done.

I think that once powders are available again, and I can get some CFE223, I might try working it up slowly and see what it will do. Historic top factory loads (now discontinued) for the 9.3x66 with the 250 gr Nosler Accubond was 2750 fps, so I'll not push past that, as it will already do what I want from it. This should be doable since the 9.3x66 has about 12% more case volume than the Whelen.
 
Interesting, is that measured velocity or guesstimated? What sort of pressure you running at? I bet it is pretty warm... I couldn't find any data for the Whelen using that powder, so would be cautious on the side of safety.

The only powders I could get my hands on over here before the shelves ran completely try was Rx17 and N150, so that is what I'm limited to right now. Both are bulky powders on the slower side for this cartridge, but are mild mannered and work well enough to get the job done.

I think that once powders are available again, and I can get some CFE223, I might try working it up slowly and see what it will do. Historic top factory loads (now discontinued) for the 9.3x66 with the 250 gr Nosler Accubond was 2750 fps, so I'll not push past that, as it will already do what I want from it. This should be doable since the 9.3x66 has about 12% more case volume than the Whelen.
@fsrmg1
That was chronoed velocity using speers load data in a 25 inch barrel
cfe223 sits between Varget and H4350 and is a ball powder so good load density also very accurate in my rifle and eliminates copper fouling well
Bob

Screenshot_20210711-135801_Drive.jpg
 
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@fsrmg1
That was chronoed velocity using speers load data in a 25 inch barrel
cfe223 sits between Varget and H4350 and is a ball powder so good load density also very accurate in my rifle and eliminates copper fouling well
Bob

View attachment 423897
Very impressive! I need to get me some of those new powders! Does Speer have any data for the 9.3x62 listed?
 
Very impressive! I need to get me some of those new powders! Does Speer have any data for the 9.3x62 listed?
@fsrmg1
This is off the speer site for you
If you like I can have a look at load from a disc for you for cfe223
Bob
Screenshot_20210913-062658_Drive.jpg
 
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Where did you find this?
I have just stumbled onto this site so excuse me for being a little late. Recently I have found a left handed Sako Barvarian with a 20” factory barrel. A lovely little rifle and was wondering what the velocity drop may be with a shorter tube. If anyone is interested in the 9.3x64 I have extensive reloading data which I have worked on over the last two years. This is a great cartridge when loaded with the right bullets.
 
According to the Speer Manual #15 the 9.3x62 and cartridges of this approximate bore diameter lose about 20 fps for every inch less than 24 inches.
 
According to the Speer Manual #15 the 9.3x62 and cartridges of this approximate bore diameter lose about 20 fps for every inch less than 24 inches.
Concussion due to muzzle blast is generally more important than probable velocity reduction ... unless you are target shooting at ranges of 300-1200 yards.
 
Some one earlier posted the the velocity difference between his 22” and 20” 9.3x62 with the exact same load 8 and 16 fps. I think this cartridge is somewhat similar to the 308 win where barrel length doesn’t play such a big part like a magnum cartridge. I’m thinking I should be able to reach 2600 fps with the 20” where my mate is getting 2650 fps from his 24” tube. Every rifle is different and only time will tell. Bob Mr Whelan you will be glad to know it is out at Rob’s now having a bedding and trigger job done along with a good going over to improve its function and accuracy.
 

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