I was told they only "list" the standard type but they have done the bushing style before & I could order them as a "special" direct from them or cheaper thru Grafs. That may have changed I guess. Hope not.
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7mm Blaser Mag experience?
- Thread starter midnightmalloy
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Smokinghole
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After comparing everything I'm considering just going with the .338 Blaser Mag case as a necked down to 7mm. With the neck shoulder junction at 2.153 that puts the 195 at a COAL seated to junction at ~ 3.553 which gives plenty of room to spare in any mag whether box or DM. I'd go with the .300 to not have to neck down so far but there seems to be no source for brass despite it being on Norma USA site. Norma sells 7 Blaser and 338 Blaser only it seems.
With no improvement type efforts the .338 measures:
Case Length: 2.50
Neck/Shoulder Junction: 2.153
Neck Length: 0.347
7mm measures:
Case Length: 2.350
Neck/Shoulder Junction: 2.032
Neck Length: 0.318
http://www.cip-bobp.org/homologation/uploads/tdcc/tab-i/tabical-en-page130.pdf
I actually found 338 Blaser brass for a good price at Midway. So I have that on the way to play with. I want to get a case capacity and case weight measurement. I bought the only 25 pack at $1.80 ea though.
With no improvement type efforts the .338 measures:
Case Length: 2.50
Neck/Shoulder Junction: 2.153
Neck Length: 0.347
7mm measures:
Case Length: 2.350
Neck/Shoulder Junction: 2.032
Neck Length: 0.318
http://www.cip-bobp.org/homologation/uploads/tdcc/tab-i/tabical-en-page130.pdf
I actually found 338 Blaser brass for a good price at Midway. So I have that on the way to play with. I want to get a case capacity and case weight measurement. I bought the only 25 pack at $1.80 ea though.
midnightmalloy
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I was told they only "list" the standard type but they have done the bushing style before & I could order them as a "special" direct from them or cheaper thru Grafs. That may have changed I guess. Hope not.
Maybe I will have to call grafs again.
midnightmalloy
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At that point you are basically at a 28 nosler so why not just go that route and save the hassle of forming brass? That's why I went with the 7mm blaser as it seems to have "enough" but "not too much!"
It's a 28 nosler with a long neck, less shoulder angle. I really like the idea of a 7mm blaser improved, blow the case out a bit, up to 35° shoulder, probably get 88 grains capacity. Due to efficiency I bet it would run with the 7mm-300 Win, probably have 180s @ 3150+- in a 26" barrel.
midnightmalloy
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Some guys have done this and I think all the info was on page 2-3 of this thread. Shawn at defensive edge did it if I'm correct and I think has the reamer.
His +p throat design is something I'd go away from. Helps to keep psi down and add more powder for a bit more velocity. But stepped throats are known to wear faster than standard lead from the reading I've done, everyone's mileage varies tho.
Smokinghole, just curious, I'm not seeing the 300 Blaser Magnum brass listed on the norma USA brass listings site?
Smokinghole
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https://www.norma.cc/us/Products/Components/Cases/
Sorry its not Norma USA, I saw the US in the URL and had mistaken that as a US site.
Aren't the dimensions of the 300 blaser very similar to the 30 nosler? Full 2.5" length cases?
Smokinghole
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I realize now that the 28 Nosler case is a bit shorter than I was thinking. I guess I was thinking of RUM cases. Still a 33 Nosler case would be better necked down to 7mm. Shorter shoulder longer neck.
It'll be interesting what IMR 8133 can do in the straight 7 Blaser case with the 195s. On Hodgdons site it's showing top velocities in a few cases around these capacities.
It'll be interesting what IMR 8133 can do in the straight 7 Blaser case with the 195s. On Hodgdons site it's showing top velocities in a few cases around these capacities.
Smokinghole
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That's probably why .300 Blaser isn't sold in the US. They are practically the same case with ever so slightly different lengths and shoulder angle.
Smokinghole
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After checking some cartridge diagrams I've ordered some 33 Nosler brass and a FL die with bushings to form a 7mm Magnum that's sorter than 28 Nosler, had a decent neck length, and will mag feed 195s from a AICS. Should be a pretty easy round, hardly a wildcat, high quality dies available, Nosler (Norma) brass, and plenty of boiler room.
Did you compare it to the 30 nosler? I was under impression that the 26/28 had same shoulder, and the 30/33 had same shoulder. In that case, start with the 30 and save a step in neck in down? Just a thought.
