Anybody built or shot a 6.5x55 AI?

I spent the afternoon at the range with a very knowledgeable shooter--an accuracy specialist, really--and while we all know 6.5s are hot right now--in various chamberings--the 6.5x55 AI seems particularly attractive.

TIA,

flaco

The swede is almost identical cartridge as the .257 Roberts and I can see no reason why the gains made to the Roberts wouldn't be roughly the same with the Swede.

Right now I'm pushing a Northfork 120 grain hollow point at 3,045'/sec on a standard swede case from a 21" barrel on a VZ-24.....

Maybe you should see just how far you can push the stAndard Swede before doing the AI thing.

Are we using the term AI just a little loosely? Some cartriges Parker never IMPROVED. Some are improved and have different form ( shoulder angle tapper and such.)

It would seem that blown out cases arbitrarily get the Tag AI. Early on there were wildcaters that IMPROVED cartridges long before Ackley. Don't mean to steal any deseved thunder here but it would be communicative if we all were singing from the same hymnal. roger

Roger,
I am assuming that it's common terminology to refer to cases with removed taper and altered shoulder angles as "AI".......and this is not relevant to whether or not Mr. Ackley ever actually experimented with the case in question.

The single greatest exception to this are the Gibbs improvements but they cannot be fired in the parent chamber as the AI round can .
but the Gibbs cannot be fireformed in the new chamber like the AI rounds can.

quote:

Originally posted by bartsche:
Are we using the term AI just a little loosely? Some cartriges Parker never IMPROVED. Some are improved and have different form ( shoulder angle tapper and such.)

It would seem that blown out cases arbitrarily get the Tag AI. Early on there were wildcaters that IMPROVED cartridges long before Ackley. Don't mean to steal any deseved thunder here but it would be communicative if we all were singing from the same hymnal. roger

You are correct Roger. A lot of folks throw the term AI around when referring to most Improved cartridges based on a standard parent cartridge. I am guilty of it myself at time. But in reality, those cartridges that Ackley himself didn't come up with he referred to as simply "Improved". If there was a person behind a particular design change to a standard cartridge then he would give credit in parenthesis ( ) after the word "Improved".

As for the 6.5x55 Improved, Ackley lists it as the 6.5x55 Improved Arch, which "is the forerunner to all the other Arch "Improved" cartridges based on the 6.5x55 Swedish military cartridge". Quote courtesy of P.O. Ackley's Handbook for Shooters and Reloaders, volume 1.

Sheesh, boys-

Didn't mean to step on anyone's toes.

I come into this conversation with the innocence of ignorance.

LOL.

I've read that certain cartridges aren't worth the small improvement.

In this case I'm thinking a net gain of improved velocity (for long range shooting) and additional case life.

Without burning out throats, like the 6.5-.284.

Can we address those questions?

Improved by Ackley himself, or anyone else?

TIA,

flaco

Or even compare and contrast with the 6.5x47, which is by all accounts a fine chambering, with the added benefit of Lapua brass?

You might look for info on the 6.5 B.J. I think it is. It is an improved 6.5x55 designed by Bob Jourdan and written up in "Precision Shooting" magazine several years ago. I read a post by someone somewhere recently who was shooting one but I don't remember where.

quote:

Originally posted by vapodog:
... but they cannot be fired in the parent chamber as the AI round can.

I'm a bit confused (not an abnormal situation from time to time) but I thought parent cartridges could be fired in the AI chamber but not the other way around since the AI is a greater capacity round and wouldn't fit in the parent chamber.

I'm going on info from a friend that has several AI chamberings, he tells me that AI brass can be fireformed by firing the parent round in the new chamber. What am I missing, did I get the wrong info?

BTW, if you can fireform brass, what kind of accuracy can one expect when firing the parent in the AI chamber? Is there any drop in accuracy?

quote:

Originally posted by Recoil Rob:

quote:

Originally posted by vapodog:
... but they cannot be fired in the parent chamber as the AI round can.

I'm a bit confused (not an abnormal situation from time to time) but I thought parent cartridges could be fired in the AI chamber but not the other way around since the AI is a greater capacity round and wouldn't fit in the parent chamber.

I'm going on info from a friend that has several AI chamberings, he tells me that AI brass can be fireformed by firing the parent round in the new chamber. What am I missing, did I get the wrong info?

BTW, if you can fireform brass, what kind of accuracy can one expect when firing the parent in the AI chamber? Is there any drop in accuracy?

You are correct.....I misspoke for sure....the parent rounds can be fired in the AI chambers and not conversely...

quote:

Originally posted by flaco:

I've read that certain cartridges aren't worth the small improvement.

In this case I'm thinking a net gain of improved velocity (for long range shooting) and additional case life.

Flaco,

Reducing taper and steepening shoulders increases case capacity which increases velocities. The amount of velocity gain is proportionate to capacity gain. The usual claim is a 7-10 percent increase with Ackley's reduced body taper and 40 degree shoulder which would also yield similar results if ones name is not Ackley.

It has been my experience that you get better case life with the steeper shoulder, less case shift, and the potential for a little longer throat life is there as well. For handloaders looking to boost performance and reduce case shift, which can affects accuracy, the improved varieties are something to seriously consider. The velocity gain by itself makes the conversion attractive.

quote:

Originally posted by Westpac:
[QUOTE]Originally posted by bartsche:
As for the 6.5x55 Improved, Ackley lists it as the 6.5x55 Improved Arch, which "is the forerunner to all the other Arch "Improved" cartridges based on the 6.5x55 Swedish military cartridge". Quote courtesy of P.O. Ackley's Handbook for Shooters and Reloaders, volume 1.

You still da man,Westpac. roger

Thanks, Malm-

flaco

Design your case with minimal body taper, a thirty or 40 degree shoulder and tighter neck. Have one of the Dave's make you a reamer and call it the 6.5 Flaco. That should put you well on your way to the accuracy Mauser you want to build.

quote:

Originally posted by flaco:
Sheesh, boys-

Didn't mean to step on anyone's toes.

I come into this conversation with the innocence of ignorance.

LOL.

I've read that certain cartridges aren't worth the small improvement.

In this case I'm thinking a net gain of improved velocity (for long range shooting) and additional case life.

Without burning out throats, like the 6.5-.284.

Can we address those questions?

Improved by Ackley himself, or anyone else?

TIA,

flaco

Or even compare and contrast with the 6.5x47, which is by all accounts a fine chambering, with the added benefit of Lapua brass?

It seems to me that the 6.5X55 is a pretty well designed cartridge in its' original form. I just reviewed the treatment of the 6.5X55 Improved Arch in the Ackley book. It appears that the data shown may be derived from the use of a 26" barrel. If so, the velocities given for the max loads don't seem much higher than what the standard round would have delivered from a tube of like length. This gives me a little more confidence in stating that the original design is quite good without needing improvement-sort of like. "it is hard to improve rounds based on the .308 Win. case"......

quote:

Originally posted by El Deguello:
I just reviewed the treatment of the 6.5X55 Improved Arch in the Ackley book. It appears that the data shown may be derived from the use of a 26" barrel. If so, the velocities given for the max loads don't seem much higher than what the standard round would have delivered from a tube of like length. This gives me a little more confidence in stating that the original design is quite good without needing improvement-sort of like. "it is hard to improve rounds based on the .308 Win. case"......

No doubt the original is a great little cartridge, but the velocity claims back when those manuals were written, were, for the most part, WAY less than what one could realistically expect using today's powders, even with shorter barrels. Also, today's chronographs are a lot better too.

quote:

Originally posted by El Deguello:
It seems to me that the 6.5X55 is a pretty well designed cartridge in its' original form. I just reviewed the treatment of the 6.5X55 Improved Arch in the Ackley book. It appears that the data shown may be derived from the use of a 26" barrel. If so, the velocities given for the max loads don't seem much higher than what the standard round would have delivered from a tube of like length. This gives me a little more confidence in stating that the original design is quite good without needing improvement-sort of like.

Modern powders and better chronographs benefit the parent case as much as the improved cases.......and as it is with the 257 Roberts AI.....we can expect to gain (apples to apples comparison) 1/4 *X velocity for an addition of X% increase in velocity......in practice we find this is usually about a 3% increase in velocity for highly tapered cases.....

Simply stated....Ackley made a lot of press taking an underloaded factory case such as the .257 Roberts which was loaded to 45,000 PSI (or there abouts) and changing the shape of the case and then loading it to 75,000 PSI and claiming the gains was due to his changes in shape!

Properly loaded the parent case will produce almost as much as the AI case.....so much so that the actual gains in fireforming brass is negligible and unnoticeable in the field...

One would be far far better off rechambering to the 6.5-06 than the AI version of the Swede.

quote:

Originally posted by vapodog:
in practice we find this is usually about a 3% increase in velocity for highly tapered cases.....

Do you have actual experience with improved cartridges? What is your personal experience regarding the difference in case capacities before and after fireforming? Have you actually measured the difference?

quote:

Do you have actual experience with improved cartridges? What is your personal experience regarding the difference in case capacities before and after fireforming? Have you actually measured the difference?

And do you swear to tell the truth.....the whole truth.....and nothing but the truth.....so help you god???


As far as the Chronos go.......I would like someone to explain to me just how do they calibrate one????

How the heck would you know if it was really accurate or not?

quote:

As far as the Chronos go.......I would like someone to explain to me just how do they calibrate one????

There's a couple things I really don't care to have calibrated....one is a reloading scale and the other is a chronograph.

With the scale I can weigh a few bullets from 40 grains to 200 grains just to insure it's working in some reasonable fashion..... and with a chronograph I can shoot a 22 LR and a 223 and a 30-06 over it to see what readings I get ....again to insure it's working reasonably right.

I've never found a reason to use actual check weights or some "proof" loads

If you're serious about calibration you could try to arrange two or more chronographs in a row to see if they all read close to the same figure on a given shot over all of them simultaneously.

Yes, this isn't calibration but my chrono has no adjustment to correct it if it wasn't in calibration......and I've never had a time that I wanted to adjust it.

Thanks, Z-

Good to see you posting.

vapo-

Were I interested in 6.5-06, I'd use 6.5-284. It's target rifle standard, with Lapua brass available.

Still, it eats barrels.

flaco

flaco,

Don't you remember the 6.5 x 55 BJAI that I built on a 24/47 from over on the sporterizing board?

You can get 100 - 150 fps more out of it than a 6.5 x 55, but for some reason loading it up sends the shoulder forward enouth to require full length sizing.

After making all the dies, etc I came to the conclusion that I really like the stock 6.5 x 55. Remember that the loads in most reloading manuals are for Swede actions and the 98s can be loaded hotter.

My 6.5 x 55 reamer has a long throat which allows seating those long, thin bullets way out - effectively increasing case capacity.

I get right about 3000 fps with 140 gr bullets. With a high BC they fly forever.

quote:

Originally posted by triggerguard1:
As far as the Chronos go.......I would like someone to explain to me just how do they calibrate one????

How the heck would you know if it was really accurate or not?

I posed this question to my buddy Rick0311 and he contacted the folks at Oehler. This is how it was explained...

"It’s all about the frequency of the oscillator in the computing unit of the chronograph. As long as the frequency of the oscillator is known...and as long as the screen's beams are spaced at a known distance...then it is
simple math to calculate the time interval of the beams being interrupted by the bullet
and translate that into FPS."

Thanks Rick!

quote:

Originally posted by Westpac:
As long as the frequency of the oscillator is known...."

Hence the problem, but at least a guy would know at that point what he needs to know about something he knows nothing about.....

Flaco,

I am working on building one right now. I don't know if the improved cartridge is actually an Ackley or not - to me it doesn't really matter. I haven't decided whether I want to try the RCBS version or the "Ackley". I decided to try this cartridge because I love the 6.5 and I happen to come across a M48 Mauser action that feeds "Ackley" cases as is with no modifications. I thought I would take advantage of this and put together a nice little "mountain carry rifle".

I have spoken with several people over the years that run AI chamberings. My former boss runs a 7x57AI. I guess they have a love hate relationship. He isn't real happy about the accuracy some times and the hassle of dealing with the cases. On the other hand he loves it.
As far as velocity improvements - from memory so bare with me - 50-75fps is what he claims. He is a cautious loader (like me) and pushing the envelope into the readzone is not a practice he uses nor me either. If you have a strong action with good gas handling capabilities I imagine you can live on the edge for years and never have a problem. As for me, gas in the face it not someting I care to repeat - it only takes one time. Another rant of mine - sorry.

My advice on the 6.5 - Try it. You'll never know unless you give it a try. Life is too short not to go for it.

Hope this helps some.
Eric