[GMFWoodchuck]

We have the 280 AI which is basically a 280 remington that's been "improved." And it seems to be fairly popular (compared to other wildcats anyway). But I don't recall ever seeing any 30-06 improved chamberings? Surely there is a such creature around somewhere. I'm guessing it would be somewhere in between the 30-06 and the 300 win mag performance wise.

 

[MikeG]

It's in one of the Nosler manuals, 4th or 5th edition, I think.

 

[broom_jm]

Everything I've seen shows the 30-'06AI as being 100-150fps faster than the original. Some would argue that the '06 is too good "as is" and doesn't benefit enough from an Improved chambering. The rounds which see the best increase from the AI changes are those with a shallow shoulder, long case neck and a significant taper. Many of the standard and magnum cartridges we shoot today started out as experiments to make those kinds of improvements to older, less-than-ideal case designs.

 

[TinkerDave]

PO Ackley's reloading manuals (I think vol 1) gives some info on this wildcat. The 280 Rem is the same as the 285 OKH and the 7-06 wildcats. The Ackley Improved versions of both the 30-06 AI & 280 Rem AI (as well as any Ackley Improved cartridge) generally allow you to fire factory ammo in said improved chamber and then reload this brass to levels providing increased performance.

 

[kdub]

Yes, Indeed. P.O. Ackley (Vol. I) states the 30-06 is a good cartridge to improve, especially when desiring to shoot 180 and heavier bullets.

Personally, considering the many wildcat chamberings I have owned, the 30-06 would be one of the last I would consider for such "improvement". But, then again, that's just me.

 

[GMFWoodchuck]

I just thought with all this talk about "improving" cartridges that it was odd that the 30-06 always seem to escape the converstation. The others were all just fine and dandy before "improving" so why not the 30-06 too. Especially with the 280 improved being a semi-factory round now.

 

[unclenick]

The old complaint I'd always heard about the .30-06 AI was that it just used more powder to get to the same performance as the .30-06. Since the sides of the .30-'06 case don't have a lot of taper to begin with, the Ackley change only increases the case capacity by about 3 grains of water. My measuring records show a 203 grain .30-06 case having about 69.2 grains of water capacity and 203 grain .30-06 AI having about 72.5 grains of water capacity. This is not in full agreement with QuickLOAD's default numbers, which show even less difference.

At the time Ackley was making his rounds (pun intended), powder selection was more limited than today and the state of electronics was such that most folks didn't have access to a chronograph to measure performance difference. So the idea that the performance was the same would have most often been based on trajectory and observed results on game, which must have appeared to be about the same.

I don't own one of the AI incarnations of the '06, so I worked up equal pressure loads of the same powder and bullet in the '06 and '06 AI in QuickLOAD, using the case capacities I mentioned earlier. The velocity predictions only give about a 35-50 fps advantage for the improved version of the '06. This is regardless of whether its a 150 grain bullet over IMR4895 or a 180 grain bullet over IMR4831. That difference is within muzzle velocity extreme spread for many loads, so, assuming it is an accurate comparison, you can see why folks without chronographs might conclude there was no advantage to the AI version?

Had Ackley chosen to shorten the neck to the length of a .308 neck, then he'd have got a bit more room and bang for his buck with the the '06 AI. But neck shortening isn't part of his formula for improving cases. Besides, back when the round was devised, most folks took it as gospel that a shorter neck meant poorer bullet alignment and was undesirable. Ackley devised the .30-06 AI in 1944, but it wasn't until Middleton Thompkins win of the National Highpower Championship with a .308 in 1963, repeated in '64 and again a few non-consecutive years after that, did this bit of ballistic dogma begin to be questioned. I was still hearing it about the .223 and .222 in the 1980's, so it takes awhile for some of these ideas to be put to rest.

If you want a .30-06 AI, I think your purposes have to be the AI form's reputation for better case life and lower bolt thrust. Figure to budget an extra 4% for powder.

 

[sionaprhys]

I did own a 30'06 AI. What little difference there was between it and the standard '06 was negligible. You'd see a greater velocity gain by adding a couple of inches of barrel length.

 

[Savage99]

I fell for the stories of less stretching etc from a so called improved chamber and have a few rifles so gouged out. The first is understandable as I got it for the rifle, a rare to find High Wall in the 60's.

Later I had a 06 Imp. done and then a .375 H&H Imp. There is no real so called improvement with the imp. However its fun for some and somewhat harmless.

 

[338 Hammertyme]

I did the AI thing many years ago and found that the smaller cases such as the 223 and 30-30 and such had marked improvement in velocities. As in several hundred fps velocity gains depending on bullet weight.

Off the 06 case I was pretty disappointed in velocity gains and personally could not stand the look of the case! ABout 25 years ago I went the Gibbs route and never looked back. Then the crummy throw away case came about and for a while I just shot the various magnum chamberings as I got very tired of trying to get my old 30 Gibbs velocities with the new cases and loosing the primer pockets after 2-3 reloadings.

Then in the early 90's someone turned me on to the RWS cases and I was back in business and very happy with those awesome cases.
6.5,7mm.30,338 Gibbs configurations were matching their belted Magnum cousins long before the short mag craze. The rimmed 7X65 R cases are easily the best quality 06 sized cases I have ever used. To date I have never lost a case due to primer pocket expansion be it a 280 Remington RWS case or the 7X65R case. Currently I am working on a project using 7X57 and 7X57R case and they too are of the same strength and quality.

Neal

 

[broom_jm]

I fell for the stories of less stretching etc from a so called improved chamber and have a few rifles so gouged out. The first is understandable as I got it for the rifle, a rare to find High Wall in the 60's.

Later I had a 06 Imp. done and then a .375 H&H Imp. There is no real so called improvement with the imp. However its fun for some and somewhat harmless.

I guess "improved" really is a subjective term, in this case, but did you not get better case life and less stretching out of your improved cartridges?

Also, I find it curious that you lump the 30-'06 AI with the .375H&H Improved. That apples n' oranges! The original '06 case doesn't leave much room for improving, but the old .375H&H had a long, sloping shoulder and an excessive amount of case taper. It was, in fact, these attributes that led many creative gunsmiths to "improve" both 300 and 375 H&H cases into many of the more efficient belted magnums we use today. Is it your contention that the 375H&H Improved was no better than its parent?

 

[WyoHunter]

I love the looks of a 40 degree shoulder. Sometimes that's all it takes to convince someone to try something different. Never heard of an "improved" cartridge performing worse than the parent cartridge.

 

[Savage99]

I guess "improved" really is a subjective term, in this case, but did you not get better case life and less stretching out of your improved cartridges?

I got less case life and more stretching with the blown out, straight tapered chamber. The case walls grip the chamber and stretch the case!

Also, I find it curious that you lump the 30-'06 AI with the .375H&H Improved. That apples n' oranges! The original '06 case doesn't leave much room for improving, but the old .375H&H had a long, sloping shoulder and an excessive amount of case taper.
The .375 H&H does not have a long slopping shoulder. Its 15 degrees which is about the same as the 30-06!

The 375 H&H does not have an excessive amount of body taper. Its conceeded to be the most reliable dangerous game cartridge ever designed. The body taper is for reliable feeding and extraction. Its the so called improved designs that don't feed as well!

It was, in fact, these attributes that led many creative gunsmiths to "improve" both 300 and 375 H&H cases into many of the more efficient belted magnums we use today. Is it your contention that the 375H&H Improved was no better than its parent?

Yes the so called improved 375 is not as good as the original 375.

 

[broom_jm]

Not to get too far off-topic here, but the original 375H&H has a 12deg-45' shoulder and .065" case taper, from rim to shoulder. By comparison, the 30-'06, in its original configuration, has a 17deg-28' should and only .034" case taper...about half. When you contrast those types of numbers with modern cartridges, both could certainly use some improving!

Please don't pollute the forum with falsehoods about AI'd cases gripping chamber walls and causing undo stretching of the web area. Any such problem, along with incipient head case separation, is a direct result of headspace issues in the chamber of the firearm...period. A properly cut chamber and new brass used in the fire-forming operation will all but eliminate stretching in the web area of AI'd cases. Any cartridge that you can feed into the chamber of a firearm will set back against the breech upon firing LONG before the case grips the walls of the chamber! Talk to a competent gunsmith and this will be clear.

Most people who wind up disappointed by an "improved" rifle cartridge get that way because they started out with unrealistic expectations, or the person who built the gun did not do a very good job. Some cases benefit more from the process than others, but to decry AI modifications as a whole, instead of simply acknowledging them for the minimal gains they offer, is unwarranted. If your experience with the Ackley Improved rounds was not satisfying, that is unfortunate, but the process itself is entirely too common and accepted to be as wholly ineffective as you suggest.

 

[kdub]

OK, guys -

Let's not become ungentlemanly in our discussions/disagreements on issues. We can agree to disagree in a manner that befits the board. Calling other folk"s posts as untrue or falsehoods does nothing to enlighten each other or fellow members on the topic. Find another way to argue your case.

 

[Savage99]

broom_jm,

Nosler #6 shows the shoulder angle of the .375 H&H to be 15 degrees. The Sierra manual I have shows 12 degrees, 45 minutes and the NRA's "Handloading" actual chamber drawing shows 15 degrees.

You listed the total taper for the longer 375 vrs the 06. Thats not the right way to measure taper.

 

[broom_jm]

Savage99,

First you say that AI cartridges aren't worth the effort because they don't gain much over the standard offering. I freely admit that the differences between a standard and AI cartridge are minimal, but don't you see that you're splitting hairs on the shoulder angle and case taper of the old 375H&H? How is the difference between 12 degrees, 45 minutes and 15 degrees any more important than the 3-5% of velocity gain you might get from an AI'd cartridge? Same thing with the case taper: The '06 has a 50% reduction in taper over a distance that is only 10% shorter. That's called an improvement in case design.

The simple truth is: Your experience with an AI was not a good one, but most people enjoy theirs a great deal. The point of this thread is to discuss the 30-'06AI, which is not one of the better examples because it is already a pretty well-designed cartridge. However, many other rounds have been measurably improved, especially in the eyes of the gentlemen who shoot them.

If you take a good hard look at all of the various off-spring that the 300 and 375H&H have spawned, over the years, you will see that they ALL exhibit AI-like "improvements". Furthermore, all one has to do is examine the dimensions of virtually any new case that was introduced in the last 50 years to see that P.O. Ackley's experiments were of value. If you can't understand and acknowledge these things, we have no basis for a meaningful discussion.

I respect your years of experience but sometimes you have to be wise enough to see that what you used to know, many years ago, might not be as true as you once thought. Things change and improvements are made, even if they are not quantum leaps forward.

 

[GMFWoodchuck]

Well, when I originally started this thread I was only expecting to gain a 100fps or so anyway. That's all you ever get with an AIed cartridge, no matter the chambering. That aside, perhaps because the 30-06 isn't a high intensity" round like the 308 the improvements could be better gained elsewhere like barrel length and sheer PSI. So maybe even the cartridge reloading life isn't really all that noticeable when improved because the 30-06 isn't loaded to quite as high a PSI as some of the others are.

But, why the controversy? People don't argue over how much better the 308 is to the 307win or the 300 savage. Let's face it, they are all almost ballistic twins. The same with the 30-40 and the 303. I just brought it up, because I'm still surprised with all the wildcatting that there is, the the 30-06 imp isn't more popular. Let's be real, the 30-06 loyalty is a bit much sometimes No one complains about the 308, or the 270. They both are variants of the 30-06. So why the gripe over the AI variant?


And no one can tell me that if they took a 280 rem ( the should length being a tad longer than either the 06 or the 270 to prevent chambering into a 270 rifle) and necked it up to a 30 cal, and then improved it that way that the numbers would not be quite a bit better. No not 300 win/300 norma levels. But enough to make it fun just like the 22-250 AIs and the 280 AIs. I'm willing to bet that one can gain 150 fps if basing a 30-06 AI variant off of a 280 rem shoulder length cartridge and loaded up to 62-63000 PSI.

 

[GMFWoodchuck]

OK, guys -

Let's not become ungentlemanly in our discussions/disagreements on issues. We can agree to disagree in a manner that befits the board. Calling other folk"s posts as untrue or falsehoods does nothing to enlighten each other or fellow members on the topic. Find another way to argue your case.

Yeah....Let's not get this locked up over silliness. Just because one guy likes turbos and the other likes superchargers doen't mean they have to fight over it.

 

[Savage99]

The K cartridges by Kilbourn which started the so called 'improved' game and later the Ackley versions have been a source of fun for some. It makes them happy I suppose and I am all for that.

I can take the so called Kilbourn or Ackley cartridges or leave them. They are not a big problem. Just not worth it thats all.

It does not seem that these designs are 'worth it' either to those who might make money selling them. I don't think any of them have become commercial.

The 280AI is close as Nosler may make some up in their rifles. There was talk that Kimber was considering the round for their new 84L rifle. I was thinking of a 84L in a 7mm off of the 30-06 case to be a lighter 'magnum' than the old cannons that I have. I would buy a 280 Rem. or a 280 Rem AI if it were commercial. Seems that Nosler will not produce proof rounds. They say thats whats stopping Kimber from chambering it.

http://www.nosler.com/riflemodel48home.htm

Here are 'hand assembled' 'factory loads'.

http://www.midwayusa.com/viewProduct/?productNumber=980745