30-06 Ai
- Thread starter bingo1010
- Start date
You get other benifits, reduced bolt thrust, never have to trim a case again. I had an 06 AI, most signifigant velocity gain was in the heavier for class bullet weights, 200 gr Sierra @ 2650(actual on a chrony) with no pressure signs.
Andy
Andy
762nato said:
That has never been proven, unless you go back to Ackley's "experiments" and accept his hypothesis verbatim (and he was biased).
Bolt thrust is based on the product of the inside area of the casehead and the pressure. In a dry chamber, the cartridge body will firmly grip the chamber walls, and only the unsupported part will have the freedom to stretch and exert force against the bolt. The notion that tapered cartridges will "squirt" out of the chamber is in my opinion nonsense.
Andy said:
Agreed. Check out varmintal's website for a finite state analysis of this. His conclusion is that the brass itself has basically zero influence on bolt thrust. Assuming zero friction in the chamber (leaving the cartridge completely free to 'squirt'), the bolt thrust was only 5,000-ish psi higher. And zero friction is a physical impossibility, of course. Real world numbers would likely be in the 2% range, at MOST.
And if you want to avoid trimming brass, neck-size
There is no real *need* to ackley cartridges as there is little to be gained in most cases. You WOULD end up with something slightly different, which imho is the primary motivation. There *are* also some significant performance improvements to be had with *SOME* cartridges - ones that have highly tapered cases like the 22-250, for example. But make no mistake - the gains are exclusively the product of increased capacity. There's no such thing as magic. If you're getting a 20% performance improvement from a 5% capacity improvement, then something (pressure) is not equal. Traditional Pressure signs have never been a foolproof way to determine actual pressures. A rifle with extremely tight tolerances may not show any of the traditional pressure signs until WAY WAY above rated pressures.
I disagree with the idea that case thrust from tapered cases in nonesense. Rechamber a few of the big old tapered cases like .45/70, .45/90, .45/120, .50/70, .50/90 and .50/140 and you will see case head thrust become very real. Now, that is a whole different size and shape than a .30/06 to .30/06 AI for sure, but the principle is the same, just smaller effects.
- Location
- Vancouver Island BC
I loaded up a standard 06 with 56.5 grains of IMR 4831 under a 220 RN Hornady and got 2511 fps out of a Rem 700 22 inch tube. So 2650 fps with a 200 grain bullet isn't a big jump in velocity. I think the 220 will kill just as fast and penetrate a little further.
If you dont mind the low BC I would agree, if you are shooting a little farther away the 200 will easily out perform the 220. I have owned several AI calibers, in the 22 250 the velocity increase is 200fps with a 55 gr. I am or was happy with all of them.
Andy
bingo1010,
I have built two 30-06 AIs and would not do it again. I was able to get 2900 with 180 gr partitons in both rifles, but that was hardly worth the effort and extra cost involved.
Now the 30-30 and the 250-3000 Ackley, they are another thing altogether. No trick at all to get 200 fps more with both of them.
Ted
I have built two 30-06 AIs and would not do it again. I was able to get 2900 with 180 gr partitons in both rifles, but that was hardly worth the effort and extra cost involved.
Now the 30-30 and the 250-3000 Ackley, they are another thing altogether. No trick at all to get 200 fps more with both of them.
Ted
Andy,
Depending on the action, you will see it ususally in the brass. Measure the case head expansion in a .45/70 and then rechamber to .45/120. The thrust flexes the action through case thrust and allows the case to move back and expand more. The case base dimensions are the same before. This is especially true in break action guns. The principle is the same in all guns, but these will show the effects of increased thrust more clearly. Thrust is an issue. I am not sure it's a big one in a .30/06 AI, but it does exist.
Depending on the action, you will see it ususally in the brass. Measure the case head expansion in a .45/70 and then rechamber to .45/120. The thrust flexes the action through case thrust and allows the case to move back and expand more. The case base dimensions are the same before. This is especially true in break action guns. The principle is the same in all guns, but these will show the effects of increased thrust more clearly. Thrust is an issue. I am not sure it's a big one in a .30/06 AI, but it does exist.
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Hi-Standard
CGN frequent flyer
- Location
- Republic of Newfoundland
bingo1010 said:
Assuming you handload, the old 30-06 is the ballistic equivalent to factory 7mm Remington magnum, with a vast selection of bullet weights to choose from. I don't see why you need to improve her
Hi-Standard said:Assuming you handload, the old 30-06 is the ballistic equivalent to factory 7mm Remington magnum, with a vast selection of bullet weights to choose from. I don't see why you need to improve her
no matter what you have there is always room for improvement....no?
bingo1010 said:
That cartridge has been around for a while now, it is the 300 wsm. You drop down one action size and exceed the performance of the '06 at the same time.
If you want to stick to a non-magnum standard length cartridge look at having a .280 AI built.
