gryphon
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Can one of you fellas that know these things tell me about the AI factor over the standard 358 NM ( of which I have one)
I was jolted by the first idea of one on UG`s this morning.I cannot find any refs to the AI part online.
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HuntingSchneider
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Loc: Tamworth, NSW
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Quote:
Can one of you fellas that know these things tell me about the AI factor over the standard 358 NM ( of which I have one)
I was jolted by the first idea of one on UG`s this morning.I cannot find any refs to the AI part online.
AI=Ackley Improved
Remove almost all case taper, shorten neck and sharpen shoulder angle. Increases case capacity and therefore velocity
If you were asking specifics (how much extra), then sorry I don't know.
.
-------------------- Liberals, stealing firearms since '96.
Steal one firearm, you're a thief. Steal a million, you're a Prime Minister.
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gryphon
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hhaaa I did know the AI bit but was wanting the difference (AI factor)`tween the two...I doubt if the AI version would equal the 358 STA so I wonder why bother.
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gatsby
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Are you talking about the 35 Ackley magnum? If so, the cartridge is said to be identical to the Norma magnum per P.O. Ackley's book.
-------------------- "Recoil is insignificant when there is a tiger on the head of your elephant" The Maharaja of Cooch Behar
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gatsby
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The 358 STW is way overbore.
-------------------- "Recoil is insignificant when there is a tiger on the head of your elephant" The Maharaja of Cooch Behar
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DarylS
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Gryphon - the .358 Norma is quite a straight sided case to start with & already has a short neck & good shoulder angle. Improving it probalb won't give 6gr. difference and that might give 0 to 50fps increase in speed. I don't think there would be anything close to 100fps improvement if improving it in standard form (I don't think there is a registered .358 Norma Ackley Improved Magnum ctg.) but anything is possible becasue anyone can have the reamer made & then cut a chamber with it. Like Gatsby said, the .358 Ackley Magnum is virtually identical, ballistically and load for load to the .358 Norma.
The ctg.s that give big improvements after improving were originally slightly underloaded and had quite tapered cases. After improving, they were loaded up to the capability of the ctg. in strong actions and showed wonderful improvements. Examples would be the .250 Savage and .257 Roberts. Others would be the wonderful improvements found between factory .35 Whelen and what the Whelen Improved round provides. More, are the .348 Winchester and the Improved versions along with a .375/06IMP compared to a standard .375/06. When you increase the shoulder .020" and increase the body length by 1/10", along with an increase in head to .470", you end up with an 80 gr. capacity case. In .35, that would be the Brown Whelen, which duplicated or came close to duplicating the .35 Norma Mag. Th is surely shows that for efficiency, Ackley was right - the Norma case is about at the top for efficiency. This doesn't mean you can't increase the speed, though. If you are willing to put a large enough case behind it and burn the powder with attendent bore and throat errosion, you can. Why, you can even get a 110gr. capacity case in .308 calibre now. The .50 BMG case will give a .30 even higher speeds. There might be an upper limit, though - with the 20mm case.
The .358 STW is like gatsby says - way to much powder for that bore size, with normal weight bullets, at least.
The .358 Norma will do close to 2,900fps (maybe over) with a 250gr. and top handloads with today's powders. It's been 35 years since I owned one & my memory's a bit foggy.
I can't see there being a need for more than that, but then, each to his own - my needs are not the same as someone elses - that's what's special about living in a free country. You can have whatever you want or can dream up. Remington did - HA! I have 3 or 4 I dreamed up that no one else seems to want - HA!). such is life
-------------------- Daryl
"a gun without hammers is like a Spaniel without ears" King George V
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gryphon
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Loc: Sambar ground/Victoria/Austral...
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I still cannot find any refs to the AI version online,one would think that with the knowledge sharing online that there would be a dissection somewhere.
I`m happy as the proverbial pig with my 358 NM standard.
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gatsby
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gryphon, What is the barrel twist rate of your 35 Norma?
-------------------- "Recoil is insignificant when there is a tiger on the head of your elephant" The Maharaja of Cooch Behar
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DarylS
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I'm pretty sure the .358 Norma was never turned into an Ackley Improved ctg. Of course, there are .358's on the Winchester 2 1/2" case, .358's on the .300 Winchester Mag case and .358's on the full length H&H case.
The standard 2 1/2" mag case was the base for the .358 Ackley Magnum IIRC.
I think my BRNO had a 14" twist but not sure - it could have been 12". It was exceptionally accurate with 3031 (62.0gr.) and 250gr Speer Spitzers. With a 12X scope mounted, I shot several 1/4" and sub 1/4" groups that day with that combination - shooting against a 6x47 heavy varmint rifle - all 5 shot groups. My BRNO beat him group for group that day. Yes - that was "wild" to the extreme. Sounds like BS - but it isn't - I was shootng with Alex Bulhman, a retired cattleman turned Bench Rest competition shooter.
The .358 Norma is a perfectly balanced ctg. imho, of course.(but I prefer smaller ctgs. these days)
-------------------- Daryl
"a gun without hammers is like a Spaniel without ears" King George V
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gryphon
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Loc: Sambar ground/Victoria/Austral...
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Quote:
gryphon, What is the barrel twist rate of your 35 Norma?
I dont remember at all what it was and a quick look on MAB`s website suggests its a 12 rate.
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Con
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TSE (MAB) make 1:12", 1:14" and 1:16" twisted 35cal barrels. For what its worth ... I don't think there's any practical reason to AI the 358Norma case.
Hopefully ... my donor action and barrel will be delivered to the gunsmith today ... time for me to build and get on the 358Norma train. Cheers... Con
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gatsby
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Loc: inland valley CA USA
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Quote:
TSE (MAB) make 1:12", 1:14" and 1:16" twisted 35cal barrels. For what its worth ... I don't think there's any practical reason to AI the 358Norma case.
Con
I think I had mine done in 1-14 but there was some discussion on shooting the lighter shorter bullets so maybe 1-12.
-------------------- "Recoil is insignificant when there is a tiger on the head of your elephant" The Maharaja of Cooch Behar
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