Home Forums Hunting & Shooting Custom Rifles & Wildcats 338/06 A-Square or 338/06 AI? DIfferences?

Googling has yielded nothing but confusion so here I am. Looking for a .338 30/06 length cartridge, I have been looking at these two but, it is unclear to me if they are exactly the same or, what difference exists.

Or put a different way, if I buy a used 338/06 AI how do I know if it is safe to shoot loaded 338/06 A-Square? I get one is SAAMI and one is a wildcat but, it seems pretty standardized. I guess I could always buy a rifle and cut a 1/4" off and rechamber with an A-Square reamer but, that seems pretty wasteful without any other reason to clean up the chamber.

And no, I have no love for a 325 WSM. Separate from WSM brass, 8mm reloading options are not what I want. A 338 WM is also redundant (more so) as I have a 358 Norma Magnum if I need a bigger boomer for something like Elk or an Alaskan bear.

TIA,
Sid

I do not have exactly either of what you are asking about but I do have a 338-06. I believe the A Square is basically the same as the aforementioned 338-06. They just standardized the old wildcat and put their name on it. The 338-06 AI is the Ackley improved version and is different than the A Square or standard version.
I know I like my standard version..
Les

Tankerjockey is right per my understanding. When A-Square submitted the 338-06 to SAAMI for standardization they submitted the standard 338-06 that was know to wildcatters for years and since it cost considerable money to have these cartridges standardized A-Square wanted their name on it. The 338-06 AI is the Ackley version of the standard 338-06/338-06 Asq.

338/06 thread

For this used rifle, it looks like I can safely take a loaded A-Square round and fire it and then compare the shoulder angle to see if it is 17.5 or 40 degrees and go from there. I'm not sure the case capacity differences matter in this round but, a 40-degree shoulder should headspace easier and prevent brass growth over a lot of firings.

Best Regards,
Sid

I started into the thread above & about 1/2 way down the first page gave up. It's the usual one or two dick-waving campfire experts that have only read about something, repeating it over & over 'til it becomes fact against other people with some actual knowledge of the subject.

Nosler #8 says the 338-06 A-Square has 17*30' shoulder & that standard 30-06 brass & a tapered expander is all that's needed. Sierra VI says the shoulder is 17*16'. Damned little difference. Not sure where the 34* thing came from. If there's concern go with a plain old 338-06 with the 06 shoulder. I dont own an A-Square & have never seen one in person, but I do own & shoot a 338-06 Ackley. The rifle was built about 30 years ago to get the 210 Partition to lower end 338 WinMag speeds. It was successful. The barrel is 25". We were going to test fire at full barrel length & then shorten as needed, but balance is perfect & it shoots pretty good so it stayed full length. It might have been enlightening to see how much velocity loss per inch there was. It's just fine the way it is. Using about 10 gr. less powder than 338WinMag, a case full of H4350 or RL17 in WW brass just squeaks past 3000fps.

The reason I went with the Ackley is that I was buying 1/2 the reamer anyway so might as well get something different. Both the Ackley & standard 338-06 were wildcats back then so dies cost the same. Like the improved 35 Whelen there is not a whole lot of improvement capacity wise, but there is some. I doubt that anything shot would be able to tell the difference. Since it's not a Whelen or a standard 06 the low SAMMI pressure spec for those 2 means zip. I load mine warm but brass life is excellent, primer pockets remain tight, & with the 40* shoulder case trimming is less than rare. If using an 06 case it will fireform about .030-.040" short & takes about 8 or 10 firings, or more, to get to max case length. I've also used 280 Rem & 35 Whelen brass which may need trim after fireforming. The 280 will need trim before loading after expanding the neck & pushing the shoulder back.

Edit: Good luck finding 338-06 A-Square ammo. A-Square is gone & Weatherby stopped loading ammunition. If you buy an Ackley you *should* be able to shoot factory 06 necked up with no trouble. It depends on who does the work. Minimum spec brass or a sloppy chamber (length=headspace) may give you incipient case separations maybe on the 1st firing. Since it's a handloading proposition, you can control the headspace. My sizing die is set with no reason to move it... ever. This took some fiddling & lost a few pieces of brass before all these nifty measuring tools were available & we did everything by feel. At the same setting I can resize fired brass or make new without headspace problems. I'm liking the idea of Whelen brass more & more due to the ever so slight 2ndary shoulder that gets formed with the initial sizing down, but 280 or plain old '06 works too.

Thanks!

Part of the 17 vs 34 degree shoulder angles is SAAMI vs. European standards (they use both sides of the case for the total angle vs. just the shoulder by itself).

Also, good tip on using 35 Whelan brass, though it sounds like regular ol' 30-06 might be a good way to go too!

If I am unsure of headspacing, I routinely expand new brass to the next larger neck size, then size it down in the full length resizer so it is snug but not real tight before loading it. I had a 338-06 AI but am not convinced it added much if any velocity. Feeding could be a problem, and that is why shoulders were gentle until Ackley came along and sought a way for a bit more and some fame. Most of the improvements out to be from running higher pressures. In 1957, Elmer wrote that his .333 OKH should be updated with .338 since the advent of the 338 win mag would result in much better 338 stuff vs. the old 333 Kynoch which hadn't performed very well for him. If I wanted a bit more velocity, I would just use a 26" barrel vs. the customary 22-24".

All I can add to this conversation is as follows..... and forgive me if it is of no interest to your question...

I have a 338/06 which was a rebore on a 270 barrel on a Model 70 LA.

A good friend has a 338/06 AI on a Ruger Long Action, and an ER Shaw chambered barrel...

We were together at the range one day with our chronographs... just ran into each other testing loads and happen to have the 338/06s with us..

We had several loads using the same powder and bullets... both with 24 inch barreled rifles..

Mine consistently had about 100 fps more velocity than his did using the same bullets and same powder... although his happened to have a few more grains loaded, it being an AI...

we both were shooting 200 and 225 grain Hornady SPs in ours...

the best accuracy was using H 380 powder for both of us...and also pretty close to top in velocity also...

Greg replaced his barrel ( and sold it) and rebarreled with a Shaw 338/06 barrel.... that one did better in velocity than the AI version
and was less fincky, being able to skip the fireforming step on the brass...

best of luck on your choice...338/06 is a damn fine caliber... my 338 mag has been a dust collector ever since...
I'd get rid of the 338 Mag, if I didn't have the flaw of not getting rid of an accurate rifle... the 338 Mag is also a Model 70...

Keep in mind that Ackley’s original idea around the “Ackley Improved” concept was that the chamber be cut in such a way as to headspace on the shoulder of the parent cartridge. Therefore, an “AI” chamber cut properly will allow firing of both 338-06 A-Square & 338-06 AI cartridges.

The 35 Whelen brass idea posted above would remedy the problem of an AI chamber improperly cut, but shouldn’t be necessary if properly executed.

I have a 338-06. I neck up '06 brass, easy using sizer with tapered expander. All my 338-06 ammo has '06 headstamps...

Don't think I'd go AI with that one. Seems to me the reward wouldn't justify the hassle..

DF

I don't think any are worth the hassle





+1

Some rounds benefit from AI, some not so much.

30-06 is oft said to not be worth the trouble, think I'd include 338-06 in that group.

I'd like to hear from those who think otherwise.

DF

The 375 H&H definitely benefits as does the 300 H&H

An article in Handloader some decades ago tested the .30-06 std vs. AI and iirc concluded that there was minimal difference in velocity if pressures were the same (using measurement of the pressure ring on the brass to .0001").

I think it depends upon the reason you’re AI’n.

The larger the diameter of the bullet atop an 06 case the less gain there is capacity-wise from AI’n so in that respect a 338 doesn’t seem like a good candidate.

On the other hand AI’n reduces case stretch so trimming is left to a minimum which is nice.

If you have a .30-06 in the stable and want to use 06 brass the AI shoulder will make recognition of one from another easier if things get confused.

I personally used .270 brass when I had a 338-06 and it worked beautifully, requiring an initial trim and anneal job.

If head stamp is important to you then the '06 case necked to .338 is great.

If performance is important to you take a look at the 338 RCM.
My 22" barreled one sends 225 Accubonds @ 2,750 with a dose of 61.0 grains of RL16.

It's a 338 Improved in a shorter all around package.

4 rounds in the belly too.

Mainer in AK has figured out how to do it.

Hornet, too.

DF

I built a 375 Whelen AI. The feed ramps and the lips of the magazine on the Mauser needed modification. (I hate relying on me to be doing modification on things like the feed ramp and the magazine lips.) Amazingly enough, it now feeds both a standard 35 Whelen expanded to 375 and an AI version. I would not have done that but for a couple of reasons.

The reamer and dies were available in the AI version. There was a long wait for 375 Whelen and 375 Brown Whelen reamer and dies otherwise. I was worried about the shoulder, but that would may not have been an issue as I maybe the 375 Whelen and the 400 Whelen have wider shoulders than the 35 Whelen. (I'm going from memory here, maybe it's just the 400 Whelen with a wider shoulder).
The second reason is what every one who likes AI says: "The stretching is minimized."
The third reason, is when I take out my Mauser 375 Whelen AI no one else in camp will have one.

On the other hand I have a 280 AI that I put together on a 700 action and there was no need for modification as it fed 280 and 280 AI fine. (If I had to do it over again it would be a straight 280.)

The same things on my 22-250 AI built on a 700 action, except the 22-250 AI does show enhanced performance and I think it is worth it. Basically a 220 Swift performance in a case that doesn't stretch much. I shoot maybe 200 rounds a year in my 22-250 AI.

If I were to build a 338-06, I'd go with the A-Square version.

I think MD wrote once that controlled feed actions might require more modification than push feed and that's my experience.

You have mail.

Looking at the Nosler manual it shows the 30-06 AI almost 3000 fps for the 180 out of 24" barrel. About 170 fps more than the regular 30-06. With the 200g there isn't much difference. If I didn't have a 300 H&H I might consider the AI.

Since the 30-06 Ai has never been SAAMI-ized, I wonder if they may have been loading the AI to a bit more than the 60K limit of the parent '06. That's really the only thing that would explain a 170 FPS gain using the same 180 grain bullet in both. More like 50 FPS max would be about the most that would be expected at the same pressure as the parent case.
Not that there is anything wrong at all with loading the AI (or, IMO, the parent case) to >60K PSI. I truly wish "they" would publish +P data for the 30-06 designed for modern rifles that are also suitable to the .270 Win at 65K PSI.
We (the handloading community) have managed to do this safely with the 45 Colt and 45-70, for example where data are clearly delineated by the firearms class for which they are appropriate.

Just my two cents,
Rex

That is pretty much all I do... I got a tapered expander for free from RCBS...

I have ran across a few guys, who use 280 and 280 AI brass instead, and they get a little more velocity...
but what they are really shooting is a 338/280 instead of a 338/06, even tho that is what they call it and what the barrel was stamped..

I shoot both the 338-06 and the AI version. Though never very disciplined in comparing the two, I would agree that there isn't much to be gained. I knew this going in, but am just drawn to the improved cartridges. As 358WCF so aptly put it, I'm often paying for half of the reamer anyway.

I've never had occasion to shoot factory loaded ammunition in an improved chamber, nor am I terribly concerned about having to find some in a remote country store. If this is a concern, probably best to avoid any version of the 338-06. I do use A-Square brass in the AI, mostly to have the 338-06 head stamp on the case. Headspace hasn't been an issue as I always fire form cases with the bullet jammed into the lands. Though this one is a Mauser, if the action has a spring loaded ejector, I remove it. Beyond that, it never hurts to have your gunsmith check that his reamer and your FL sizing die are closely compatible.

Redding dies come with a tapered expander, as I'm sure some others do too. I've never had a failure with sizing new 30-06 brass, though fired brass can be difficult.

There is a difference. 338-06 3.340 COAL 338 a square is 3.440 COAL. In many 338-06 chambers 338 a square will not chamber and if it does could increase pressure due to the fact it is close to the lands.

Another point many rifles will not cycle 338 a square - rugers being one example. If you are wanting a 338-06 or a square consider that you will need to cycle 3.440 length cartridges.

Early in my path of .338-06 AI. 200 grain Speer for fire forming. I built it to elk hunt, I have moved away from the 185 gr. TTSX to the 160 gr. Whitetail stopper and very accurate. If I need a rifle now, this is what I carry.

Pac Nor barrel on a Savage Weather Warrior donor, might not be sexy, but two shots two elk, did what I asked it to. A little heavy, but at the cost of the trips to Montana I wanted to be sure I could shoot it well.

Use 35 Whelen brass. My first batch has 8 loadings on them and I see no sign of fatigue. I do anneal each use.

I just love the looks of the sharp shoulder/less taper to the case! I hunted a tad over 20 yrs with a 35 Whelan AI (amongst varied other calibers too) I used the original Barnes 250X (2550-2600) and the 200X (Secant Ogive, going 2970) ) on two Plains Game hunts in South Africa. Pure poison! I've used 338WM and 340Wby on PG and elk, used the Nosler 180AB in a 338 RUM on a big Aoudad in Texas. Elk with 375 H&H, traded a 375 Wby to a friend whose clients used it on eland, 270 TSX. I always set up my hunting loads on new, fireformed brass. Never had an issue. My loads (via SWAG from QuickLoad) ran around 72K, come to find out. Few people realize that alot of Weatherby factory ammo is loaded to 72-74K! However, I had an unrelated retina problem that left me with one good eye (thank God my shooting eye! ha) , so moved on to 64K loads in most rounds now, especially magnums. With the modern powders we have now, I would not mess with Ackley fireforming, just run an '06 case into the die, presto...338/06 (ala 338 A-Square) 35 Whelan same same. I enjoy shooting the bigger animals with bigger calibers SO MUCH! Too little $$$, too little time, ha

These are gorgeous looking rounds friend!!!