.243 Ai

You forgot the wonderful .17 Ackley Hornet!

Anyway...

I'm going to have to politely disagree with ya ax. For instance, compare the cartridges in loading manuals. Do you think, for instance, Nosler is keeping something going with higher published safe velocities just to keep people buying Ackley dies? What about for those cartridges where there is nothing filling the void? I'm building a .280 AI right now, it appears I will be able to get 150s to 3100 fps safely (from published bullet makers' data) with the AI, while only to about 2950 with a standard .280 Rem.

To get more, you've got to go magnum....7mm Rem mag is next up in velocity and beats the .280 AI by about 30 fps with 150s and burns an extra 15 gr. of powder.

I do see a ballistic advantage providing false data isn't being published!
 
Little Different Take on AI's

I have a hand full of improved rounds, Swift, 257, Dasher, 6 Rem, 270/308 AI, 338 Gibbs (338/06 AI with shoulder moved .100" forward).

I don't shoot the AI's for added velocity! I shoot them so I can get the same velocities as the standard rounds with milder loads! This gives me better barrel life and more consistant loads.

Its the old "I can make my small block run with your big block".... Yep you can, for a very short period of time, then it comes apart. I can take the big block, build it realitivity mild and run with a hot small block. Drag racers have a saying, "nothing replaces cubic inches!"

As an example, I shoot my Swift Imp't at about 4000fps with 52-53 grain bullets, very very mild load for a Swift. Cases last forever and the barrel life is supperior to a 22-250 at the same velocity. I leave nothing on the table for accuracy.

I believe when you push the envelope of a particular case, you are also knocking on the door of inconsistant accuracy. I am not a fan of Hot Rodded cases.

The mistake (MHO) most make with AI's is trying to wring every bit of velocity out of the case they can.

There is no way you can make the statment there is no advantage to an improved case. There are many advantages!

What you can say is the velocities can be equaled in other manners, that I will agree with. But I beleive in doing so, you are adding wear and tear to your set up.

The only AI I have owned that I thought was a waist of time was 6mm-250 AI. What a pain in the A$$. Cases made from standard 22-250 would not last. I ended up making the cases from Lapua 243..... Never again, lol

The AI's are great rounds as long as you are willing to go through the added work and effort. Don't let anyone kid you, they are more work! Your dies have to be correct or you end up with banana shaped brass.

Venture into the AI world and leave behind the days of just screwing a die in the press, size it, prime it, dump some powder and seat a bullet. Takes alot more care and attention to detail.

Personally, I enjoy tinkering with the Ai's. Are they more trouble, ABSOLUTELY! Are the worth it to me, YES.

JMHO

Randy
 
The tinkering is most of the fun! The .280AI will be my second (I don't count they .17 Ackley an 'improved' because it is necked down before it is 'improved').
 
220 Ackley advantages ????

Hi Ramshooter:

Your take on improved cases seems to be just the opposite of what my common sense and past experience has told me.

If one makes the case capacity larger, I think that one must use more powder to equal the same velocity as the smaller case thus more barrel destruction. It is the p.s.i. that makes the velocity. There is no way that a larger case will make the same velocity without making the same pressure. A "mild" load will not do it. If this were true, the larger the case capicity the longer the barrel life would be. We all know that this is not true.

Yes, larger cases can produce larger velocities but there is a point of no return that will be reached. Look at the various .30 caliber magnums to see where this point. I learned this the harrd way back in the late 50's while working with the various .264 caliber rifles. Bigger was not better then and I doubt if is better today. If you wish to play with the .224 caliber, there are many rounds that one may chamber to increase the capifity until you are satisified that it is a lost cause.

Good shooting,

Seke
 
Seke

zeke mccune said:
Hi Ramshooter:

Your take on improved cases seems to be just the opposite of what my common sense and past experience has told me.

If one makes the case capacity larger, I think that one must use more powder to equal the same velocity as the smaller case thus more barrel destruction. It is the p.s.i. that makes the velocity. There is no way that a larger case will make the same velocity without making the same pressure. A "mild" load will not do it. If this were true, the larger the case capicity the longer the barrel life would be. We all know that this is not true.


Good shooting,

Seke
Click to expand...

You are correct to a point. Given you use the same powder in the improved case, the only way to reach the same velocity is to increase the charge to give the same pressure. Pressure equals velocity. No arguement there.

But consider this, larger case volume with slower powder equals same pressure, but with less heat and a smoother pressure curve.

When you increase the case capacity to bore diameter, typically you can use slower powders.

Example, I could never reach the same velocities with a 22 Dasher as I can with the same powder in a swift, won't happen. To push the velocity on the Dasher, you need hotter powder.

When I am refering to a mild load, I am not talking about a lighter load, I am talking about cooler with less violent pressure curves. The smoother the pressure curve, the more consistant the load.

Pressure is not what eats barrels, heat is the culprite (jmho). Trust me, I am no expert nore do I have a lab to prove it. But I can tell he difference in the number of rounds I can shoot from an improved case at the same velocity before the barrel heat becomes a factor.

For a varmint hunter, that is a plus.

Bottom line, if you shoot improved cases for increase velocities, you are no better off, in many cases you are going backwards. If you shoot them for the added versitility, you are gaining.

All of know the reputation of the Swift being a barrel burner. It was in the beginning and still is by guys that try to run them at 4200. To get the 4200, takes the same hot powders that were used in the early days.

Take that Swift case today, improve it, load it with slower powders and I'll match it to a 250 any day. And the lawn poodles won't know the difference between 4000 and 4200.

Again, just my opinion.

Randy
 
For all that stuff, I find that the Ackley case usually produces the best accuracy at a lower than maximum velocity. A 75 grain bullet at around 3,500 fps in my rifle (trued 'n tricked Rem. 700 with Schneider 26" barrel) using 47.5 grains of powder is optimal, where increases in powder charge opens the groups. The maximum load in the standard case, 46.5 grains, produces 3,400 fps - statistically insignificant. The greatest efficiency in the improved case is best utilized with heavier bullets and slower powders, but I'm a varmint hunter. So actually I could have been served by the old Roberts shape. Strangely enough, that same load is best in all three .257 Roberts A.I.'s I have owned.

In the case of the .280 Remington vs the Ackley Improved, using a 160 grain Nosler we find an instance where the 160 grain bullet can be driven at 2,810 fps with a max load vs 3,002 fps with a max load in the A.I., a 192 fps gain in the test rifle's velocity. Both these loads are listed as the accuracy load for the test powder. Other loads in both versions show the accuracy load to be the low to middle charge with similar powder. Truthfully, I don't see a significant practical gain in velocity that will translate into performance in big game hunting. Either case will do the job, as will the 7mm Mauser, 7mm-08, or .284 Winchester. Once again, it's a matter of personal preference and desire. That .280 Remington AI has a very large cool factor - justification enough to enjoy having one. I already have a 7mm Mauser M-70 and tricked 7mm Remington Magnum - so I'm set.

I have never loaded any cartridge to the maximum simply because they never seem to shoot as accurately at that level. That is a happy circumstance that adds barrel life, although barrels are a wear part, like brake pads. Barrels are consumables the same as powder and primers.
 
Flame temperatures during combustion?

Hi all:

After reading Rams00ters post I have some questions if anybody out the?re has any reliable information concerning what are the temperatures are duing combustion

From memory, I thinks that it was about 4200F for all powders. The "ball" powders were slightly cooler but not by much!

Of course time played a bit of importance in determing barrel wear as to the total amount of heat being produced. This illustrates the point that a small amount of fast burning powder was as erosive as a large amount of slower burning power. The total was about the same and was linked to the total amount of heat produced.

In any case, perhaps someone who has had a chance to use lab equipment to determine the above situations could chime in. Anybody have Bill Davis' phone number?

Good shooting,

Zeke
 
Alinwa, I must have missed something......

My 26" Hart 243 min spec, zero freebore, turn neck will push the 80g bullets at 3500 fps with extreme accuracy. I have to full length size after every firing, and trim on the second or third firing.

My 243 Ai will push the 80's at 3750-3800, never full length size and never trim a case. The 70's are going 3850 minimum and 3950 if I want to push the envelope. Yes, I have had over a dozen 243 AI's with Hart barrels, and only one standard 243 with a Hart barrel on it. I know that you know what you are doing, I just wonder from what perspective you are coming from?

I appreciate your commenton the 6 x 47...I was wondering about that.
 
Axlenut.......

"A well crafted precision barreled and chambered rifle in a standard cartridge, when fired with cases sized in properly dimensioned and adjusted dies, will negate any case stretching advantages of the improved shape. With bolt thrust less of a problem in a modern bolt action with minimal headspace, than it was in older rifles and other action types, this is not much of an advantage."

Axlenut, you are dead wrong on your above comments!!! I have seen on custom minimum SAAMI spec 223 vs 223 AI, 22/250, vs a 22/250 AI, 243 vs 243 AI, and the 6mm Rem vs 244 AI.

I am open minded to new things, try new things just for grins to see if I can learn a thing or two...no ego involved. A new and better thing is just a new and better thing...that's all. I don't give a crap about the "coolness" factor, that is tripe to me. All I am interested in is a better mouse trap.

An added bonus on the AI versions is that this design really limits trimming cases which says a lot about the Ackley limiting case stretching which can mean more case life. Ackley talked a lot about the lack of case stretching in his book, how the case grips the chamber wall instead of the back thrust of it's parent cartridge. I have yet to trim a 17 Ah, 223 AI, 22/250 AI, 6/250 AI, 243 AI, or 244 AI, granted that I do not shoot heavy bullets which would indeed push the pressure limits of the case.

It amazes me that you still have the 257 AI, was one of the two worst AI's that I have ever tried, at least compared to the 25/06. I got no velocity gain at all with the 257 AI over my 25/06's, but I did eliminate case stretching and trimming the cases.

You also mentioned something about the Ackley design leading to the cartridge likiing loads in the mid range of the powder charges...where do you come up with this stuff? Every Ackley that I have ever had chambered, had it's accuracy node about .5g-2.0g less than max for that rifle(my rifle can not read a loading manual, I have to let the rifle tell me what is a max load).

Not only that, the standard cartridge usually had a very specific, narrow powder charge where the accuracy node was found. I have found the Ackley's that I have worked with had a much broader range of powder charges that exibited extreme accuracy vs the parent cartridges. Most of the Ackley's that I have worked with were of a bullet dia of .243 and below.

I build a 6.5 Remington Mag AI a few years back, and was fire forming the 85's at 3900+ fps shooting groups in the .300 range. I sold the rifle to a friend for a long range coyote rifle before I got 75 cases fire formed...I hunted while fire forming.

It is human nature to hate something. Some people hate white people, some people hate Mexicans, some people hate whites, some people hate Indians, some people hate Ackley's...it's just that simple. I have ran into people that hate Ackley's before...they just can't help it.
 
Ackley cartridges

HI Keith:

Do you have a reliable chronograph? Your results with the 85 grain bullets in the 6.5 Ackley Improved is much better than I could achieve with tfhe .264 Win Mag. The 6.5 Rem mag has nearly the same capacity as the 6.5 06 thus both cases should yield the same results.. Improve both and guess what, the results will be the same.

As far as the idea that the Ackley design grips the chamber walls better than a non Ackley cartridge is concerned, this is just plain wishful thinking! All cases grip the chamber wall when fired. Ackley proved this by removing the rocking lugs from at least two rifles and firing them. Both guns suffered no ill effects! Isn't this what gives protrubing primers when guns with excess headspace are fired?

One last thing, how does a person Give the 6.5 Rem Mag the Ackley treatment? Isn't it quite improved enough as it is?
 
Zeke,

zeke mccune said:
HI Keith:



As far as the idea that the Ackley design grips the chamber walls better than a non Ackley cartridge is concerned, this is just plain wishful thinking! All cases grip the chamber wall when fired. Ackley proved this by removing the rocking lugs from at least two rifles and firing them. Both guns suffered no ill effects! Isn't this what gives protrubing primers when guns with excess headspace are fired?
Click to expand...

Again not trying to be argumenitive, But I disagree.

Ackley proved nothing by removing the lugs, he may of not gotten any ill effects from either one. That does not prove less bolt thrust! The only way you can prove that is with a test lab.

It only stands to reason the tappered case puts more thrust. Try a tappered case in a Contender, see how long it stays tight.

Regarding the protruding primers, this is cased by the head of the case being pushed forward and the pressure blowing the primer out of the pocket.

This is a debate that will go on long after we are both done shooting. My experiences with improved cases have good (accept the one and it was just a bad chamber job).

The only one that I load on hot side is my 338 Gibbs. It is a rifle that Iwill never shoot enough to wear out the barrel. The reason I built it was to get near 338 mag performance with out the recoil and heavy gun. One of the most impressive big bore rounds I have ever owned.

Randy
 
First of all, I would like to say that I have respect to all the posters...

a good discussion is how we all learn from different perspectives. I for one know that the human mind has to be like a parachute to work properly it has to be open to work. I hope that I never quit learning, which is why I love to read this forum with so many knowledgable people contributing.

Zeke, from my experiences in shooting Benchrest, I made the decision to apply Benchrest standards in chamber dimensions to hunting calibers. The standard 6 PPC chamber will have very minimal clearances over case dimensions, freebore to fit the loaded round, .0005 over bullet dimension throat, and 1 1/2* leade angle. These dimensional changes is what made the 6.5 Rem Mag AI so effective and accurate. I use the Ohler 35P. Your standard 264 Win mag probably had a huge chamber, with much clearance in the body, .002+ over bullet dia throat, much freebore, and large neck dia. The pressures generated worked to expand the brass, some of it blowing by the bullet due to over size throat and neck dia. instead of just pushing the bullet out of the barrel. Capture all that pressure and have it work for you by having a benchrest chamber and you are in a whole new league in terms of accuracy and speed. Add a few inches of barrel for dessert.

Ackley chambers do grip the sides of the chamber more than the standard cases with all the taper, more or less depending on the caliber. Yes, regular cartridges do grip the chamber unless they are highly polished. I like a little crocus cloth in a split wooden dowel ran up against my chamber walls at about 40 rpm to take the high spots off any tool marks while the barrel is still in the lathe.
 
Keithcandler,

My perspective is based on case life. IMO a gun isn't any good unless case life is "indefinite" a the pressures required for consistent ignition......... for instance I can make 25 cases for a 6PPC or a 6BR and use them until the barrel wears out. I expect the same from anything that I shoot. After playing with a bunch of different reamer grinds, throats and leades I came to find that while I CAN run the .243AI up into the ranges you talk about, the primer pockets go south in less than 10 reloads. Many times I was hard-pressed to get 5 reloads from a Lapua .243 case. To me this is unacceptable. IMO a case doesn't even get "good" until its third firing and in my experience with the .243AI about the time it got "good" it was on its way out. I've had the same experience with all cases based on the American .250/.308/30-06/ lines of cartridges.


I started my odyssey with the .243AI dead set to go out and PROVE once and for all that a properly built rifle based on a "standard" American case could run.

$10,000.00 later I conceded defeat! I had 4 of the barrels cut down and rechambered to 6BR and they ALL shot much better AND came within 3-4% of the .243AI velocitywise!

This new 6.5X47 Lapua case flat out DOES everything that I hoped for in the .243AI. Necked down to 6mm it will push 70gr bullets at 4000fps for 50reloads. I took five cases tonite and reloaded them 17 times using H4350, Fed primers and Euber 108gr bullets at 3200fps. The primers are still tight. I could barely get 3000fps out of the .243AI case. Sure, I could run the .243AI clear up to 3200 for 4-5 shots but that did me no good because I could never get the accuracy I wanted before the primer pockets failed. The 6X47 was (is) shooting round dots @100, none of the "Ackley Fliers".............

I LOVE Ackleys! I'm a fan of P.O, I even own a .270 built by him, complete with the original sales booklet and with his own hand buttoned barrel. I just haven't found his improvements to be really worthwhile EXCEPT for the total coolness factor.

And for the .243AI and 22-250AI there's the added problem of shoulder bounce. I have all of my "improved" reamers ground with a 35degree shoulder for this reason.


al
 
Alinwa......

that was some good info, thanks!

You must have been shooting the heavy bullets in the 243 AI which I have no experience with, I'm doing the 70's. Case life with the 70's seems to be indefinate at this point at 3850, I have yet to use the full length sizer.

I can't say that I am familiar with "case bounce".

Again, that is some darn good news on the 6.5x47 brass!

Keith
 
To Keith et al re Gibbs cartridges

Hi Keith:

Tell me about your .338 Gibbs. I built a .30 Gibbs several years ago and I have yet to shoot it. I have no idea as what I will discover when I begin to play with this thing.

Before I get to the Gibbs there is a 7mm Rem Mag that I must get to and the biggest project that I ever took on, restocking and finishing a side by side shotgun that is a SIDELOCK. I thought that I was quite the stock maker after stocking many bolt action rifles but this sidelock turned out to be a real challange!

Take care,

Zeke
 
Zeke,

zeke mccune said:
Hi Keith:

Tell me about your .338 Gibbs. I built a .30 Gibbs several years ago and I have yet to shoot it. I have no idea as what I will discover when I begin to play with this thing.

Before I get to the Gibbs there is a 7mm Rem Mag that I must get to and the biggest project that I ever took on, restocking and finishing a side by side shotgun that is a SIDELOCK. I thought that I was quite the stock maker after stocking many bolt action rifles but this sidelock turned out to be a real challange!

Take care,

Zeke
Click to expand...

I am the one with the 338 Gibbs.

I love it, shoots 210-225 grain Noslers better than any big bore I own with the acception of a 300 Win Mag that was built more on the lines of a target rig in a sporter stock.

The 338 Gibbs is much like a 338/06 Ai, but it has the shoulder moved forward approx .100".

It is a puppy dog to shoot and is about 200 fps slower than my 338 mag that pounds me into the ground. I just flat do not enjoy shooting the Mag.

The cases are a pain to form, but I think it is mostly the gun. I built it on a Ruger No 1. If you don't get a heavy false shoulder, the firing pin drives the case forward without firing in many cases. The cases that do fire have inconsistant headspace.

I found that I had to neck up 35 Whelen cases to 375, then take them in two steps, to 35, then to 338. Then the gun came alive!

I attached a couple photos showing the false shoulder it takes to form and one comparing the Gibbs to a 338 Rice (another version we played with).

I love this round so much, I am considering rebarreling a Mod 70 I have stuffed away into another 338 Gibbs.


Randy
 

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.338 Gibbs

Hi Keith:

Thanks for the information on the Gibbs. I must find time to shoot my Gibbs Where does the time go?

Zeke
 
Zeke,

zeke mccune said:
Hi Keith:

Thanks for the information on the Gibbs. I must find time to shoot my Gibbs Where does the time go?

Zeke
Click to expand...

Doesn't really matter, but you have my name wrong, its Randy.... LOL

You should shoot yoru Gibbs, I love mine.

Randy
 
keithcandler said:
"A well crafted precision barreled and chambered rifle in a standard cartridge, when fired with cases sized in properly dimensioned and adjusted dies, will negate any case stretching advantages of the improved shape. With bolt thrust less of a problem in a modern bolt action with minimal headspace, than it was in older rifles and other action types, this is not much of an advantage."

Axlenut, you are dead wrong on your above comments!!! I have seen on custom minimum SAAMI spec 223 vs 223 AI, 22/250, vs a 22/250 AI, 243 vs 243 AI, and the 6mm Rem vs 244 AI. . . .

It amazes me that you still have the 257 AI, was one of the two worst AI's that I have ever tried, at least compared to the 25/06. I got no velocity gain at all with the 257 AI over my 25/06's, but I did eliminate case stretching and trimming the cases.

It is human nature to hate something. Some people hate white people, some people hate Mexicans, some people hate whites, some people hate Indians, some people hate Ackley's...it's just that simple. I have ran into people that hate Ackley's before...they just can't help it.
Click to expand...

Keith:

I don't hate Ackley's work - indeed I communicated with Ackley several years before his death regarding various things about building a rifle. He was always accessible and willing to share his knowledge with "Joe" shooter. Ackely's successor Mike Bellm barreled one of my rifles back in the early 1980's before he became a Contender specialist.

What I said was that the Ackley Improved chamberings are not ballistically necessary - in that the gain in velocity is not offset by the need to fireform. Nor are the mechanical advantages of the case shape sufficient, in a modern bolt action, to justify the extra work. While some rifles will produce fine accuracy during fireforming, many do not. Fire forming itself can be a cause of case loss and distortion, introducing neck concentricity and headspace problems. In other words, a shooter can find a standard chambering that will duplicate the Ackley ballistics without fire forming and all the voodoo necessary to using an improved cartridge.

Case stretching is related to pressure, chamber fit and resizing protocol. In my experience, I have not found the Ackley design a cure all to case stretching and neck trimming. My barrels are chambered for a specific bullet and neck diameter with a slight crush fit on new unfired sized cases, for both improved or standard SAAMI versions. I neck turn to a standard wall thickness use neck sizing bushings and/or body bump dies, and never draw an expander button through a neck. All necks are cleaned internally and dry lubed prior to reloading. I only shoot molly coated bullets.

Case life is not a major priority for me, I purchase cases in bulk, 500 or 1,000 at a time, considering them expendable the same as any other component. I discard them after a maximum of five firings regardless of condition.

The .257 Roberts Ackley Improved is one of Ackley's success stories. Most loading manuals describe it as having the greatest velocity increase over the standard design, approximately 200 fps.. It can not match the .25-06 and was not designed to do so. That fact is also clearly stated in the manuals, and has been my experience.

I have seldom found any maximum load to be the accuracy load, except for the 6mm PPC.

My comments were directed at the novice shooter to inform as to the reality of chambering for a non-standard cartridge. If your reality is different - well that's what discussion is about! :)
 
axlenut said:
Keith:

"What I said was that the Ackley Improved chamberings are not ballistically necessary - in that the gain in velocity is not offset by the need to fireform. Nor are the mechanical advantages of the case shape sufficient, in a modern bolt action, to justify the extra work."

"While some rifles will produce fine accuracy during fireforming, many do not. Fire forming itself can be a cause of case loss and distortion, introducing neck concentricity and headspace problems. In other words, a shooter can find a standard chambering that will duplicate the Ackley ballistics without fire forming and all the voodoo necessary to using an improved cartridge."

******* "Need to fireform?" "extra work" "case loss and distortion?" "voodoo?" Where do you come up with this stuff? Work up an accurate load then go shoot, that's it. Where's the "extra work?" Fireforming loads are considerably faster than the parent case and there's no loss of accuracy. And not just "some rifles," every AI barrel I have from .17 to .257 has been very accurate while fireforming. There are no "headspace problems" and there's no voodoo.
-------------------------------------------------------------------------------------

"Case life is not a major priority for me, I purchase cases in bulk, 500 or 1,000 at a time, considering them expendable the same as any other component. I discard them after a maximum of five firings regardless of condition."

************You're preaching to the choir. Each of my guns has about 1,000 cases and I know for absolute fact that Keith has at least 1,000 cases for each gun and many more than that for some. Discarding them after a "maximum of five firings regardless of condition"??...... that doesn't make much sense but whatever floats your boat, it's your brass.

-------------------------------------------------------------------------------------
"The .257 Roberts Ackley Improved is one of Ackley's success stories. Most loading manuals describe it as having the greatest velocity increase over the standard design, approximately 200 fps.. It can not match the .25-06 and was not designed to do so. That fact is also clearly stated in the manuals, and has been my experience."

***************My experience (not from the loading manuals) has been that even fireforming it matches the 25-06.

------------------------------------------------------------------------------------

"I have seldom found any maximum load to be the accuracy load, except for the 6mm PPC."

***************AI cartridges are very accurate at max or near max velocity. MOST people who shoot them know that.

-------------------------------------------------------------------------------------

"My comments were directed at the novice shooter to inform as to the reality of chambering for a non-standard cartridge. If your reality is different - well that's what discussion is about!" :)
Click to expand...

You have some strange ideas about things. Your comments aren't "reality" and they're very misleading.
 
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