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Old September 29, 2008, 02:04 PM   #1
Magnum Wheel Man
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chambering / throating for accuracy... with both jacketed & cast bullets...

I posted this thread in the rifle section, & debated as to weather I should have posted it here...

since I got no replys today... yet... maybe I should have posted it here ???

any recommendations ???

http://www.thefiringline.com/forums/...d.php?t=312751
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Old September 29, 2008, 06:13 PM   #2
Harry Bonar
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chambering and throating

Sir;
Art Alphin of A-Square Co. inc. throats his rifles with a paralel throat.
If it is a 30 cal. he makes a "paralel" throat .0005 or .001 larger than the bullet (30 cal would be .3085 or .309 as a paralel throat for a distance and then makes the classic rifling groove dia. normal throat at the end of the "paralel" throat.
This serves several functions; first, it is not "freeboring." It gives the bullet (jacketed or cast) a good start in life and then enters the classic "throat" into the rifling.
For instance, you can load long bullets without concern over length. Second, it aligns the bullet precisely into the bore. In a 308 or a an 8mm. bullet the bullet has a good start into the rifling, contrary to the regular throat in which there will be some misalignment.
In the Lyman 311296 buillet the front of bore diameter (.300) while back at the driving bands it's 308 or .309 (depending on how you would size it).
I'm concerned about the rolling block action!
Their construction offers (while normal and safe for some cartridges) no upper support to the breech block! ALL of them have a stretch - they do not support the case 360 degrees! Not condusive to good accuracy. Case walls MUST grip the chamber therefore to reduce "case head thrust" on this action. Personally, I'd relagate rolling block actions to black powder cartridges.
However, this "paralel" throating would solve your problem.
Harry B.
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Old September 30, 2008, 09:51 AM   #3
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Harry,

That parallel throat is something I've somehow missed coming across before. Probably should not have let my CBA membership lapse, because I'm sure the Fouling Shot will have had a write-up at one time or another. Do you know, does Mr. Alpine lead into the parallel portion with a ball throat taper?

Thanks,
Nick
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Old September 30, 2008, 03:28 PM   #4
Harry Bonar
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throat

Sir;
For instance, the chambering reamer (let's take 30 cal.) would cut a paralet throat of .309 instead of a .315 tapered down to .308 to take the rifling.
This would keep the bullet aligned with the bore within .0005 within each side until it contacted the rifling taper. This way you can seat long ogive bullets out where you want them instead of crowding the powder space in the case! His manual, the best in my opinion in the world, is avaliable, (Any Shot You Want - The A-Square Shooters Manual). It's about $40.00 and covers what other manuals don't. These guys are the "big boys" of the shooting sport - African hunters and covers EVERYTHING! I have worn out my copy!
They cover case sizing and debunk the die instructions of bumping the die bottom with the shell holder! Do that, and within three shots you will experience some case head separation!
To reiterate, your chambering reamer wouldn't cut a "tapered throat" but a straight throat so far until you contact the lead into the rifling! I hope I've explained this so we can picture it.
I talked to Colonel Alphin sometime ago and he is a very direct man!
Harry B.
P.S. All of A-Square rifles have the "paralel" throat - 375s, 416s, 470s, 500s, and 577s.

Last edited by Harry Bonar; September 30, 2008 at 03:31 PM. Reason: addition
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Old September 30, 2008, 04:26 PM   #5
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Got it! Thanks. It's an interesting concept. I even have a spare reamer or two I might send out for a spot of re-grinding to give that a try. Alpin's throat isn't letting gas blowby get anywhere, either, which is probably helping the cast bullets especially.
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Old October 1, 2008, 01:58 PM   #6
Harry Bonar
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A-Square Manual

Sir;
As I understand the A-Square company at this time Colonel Alphin (impecable credentials too) is merely in a top level consulting job. A-Square at one time was sold, had some trouble and then Colonel Alphin bought it back. There was a space of time and I think the company was sold to someone else, with Art in a top level consulting and design job.
At our last talk Art was going to design a new action and told me, "the company is now in the black." Their ammo, though very exspensive, has a "triad" of bullets, the "lion load" - very frangible, a "dead-tough" good for buff and elephant and the "monoliphic solid" speaks for itself. Art is a good supplier of brass and is a SAAMI member and has standardized several cartridges (338-06 and many heretofor wildcats) - Weatherby now loads a rifle in 338-06 along with ammo for it.
It's my personal opinion, after reading their manual that jealousy amoung the industry giants hurt A-Square.
Their rifles are made from P-17 Enfields, practically re-manufactured and are the only successful conversion of that action to the 495 A-Square, the 500 A-Square and the 577 tyranosaur.
Their manual covers every aspect of hunting, shooting, all of the ballistic issues and loading tables - it is right on the line as far as I'm concerned about loading, sizing, head-spacing, bullet seating, etc!
Reamers ? I do not know if anyone is making reamers with the paralel throat but I look for them soon.
I've been so influenced by Art that I've built three 9.3X62s, two 9.3X64s, (equivalent to the 375 H&H) and several 416 Taylors (equivalent to the Rigby)! It has that "magic" big bore velocity of 2400 fps with the 400 grain bullet and fits nicely in the 98 Mauser action. (458Win Mag necked down to 416)
Are these rifle calibers unreasonable for U.S. hunting? Certainly not! These bullets don't ruin meat like a 308, 270, or (perish the thought) a belted magnum, but simply completely penetrate with the "dead tough" bullet and ruin very little meat! I love them!
Wildalaska tells me it's also good up there on about anything (the 9.3X62).
He tells me its popularity in increasing and I look for the more knowledgeable sportsmen to latch on to one.
Good shooting.
Harry B.
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