What does this mean?
Ackley Improved.
What does it mean? Is it a reformed cartridge case?
I'm looking at a Mauser in .257 Roberts Ackley Improved.
Is it worth it to go with an AI?
Are AI cases easy/hard to find?
Can I fire normal rounds in an AI gun?
I've been around guns all my life, but this is the first time I've heard of an AI.
What does it mean? Is it a reformed cartridge case?
I'm looking at a Mauser in .257 Roberts Ackley Improved.
Is it worth it to go with an AI?
Are AI cases easy/hard to find?
Can I fire normal rounds in an AI gun?
I've been around guns all my life, but this is the first time I've heard of an AI.
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Please pardon my ignorance, but could someone tell me what this means?
It is from a gunbroker auction.
"I then added the new TAC 65 22 LR sound suppressor ($200)"
"The TAC 65 is on a Form 3 in Louisiana ready for transfer to your Class 3 dealer."
I don't know what a "Form 3 in Louisiana" is, nor do I know what a "Class 3 dealer" is.
I'm thinking it is something that the average shooter would not be able to get without a special permit.
Thanks,
DSM0 -
The Ackley Improved cartridges are indeed reformed.
They have the advantage that they are fireformed by firing standard loads of the base caliber in the AI chamber, then reload with AI dies. No die forming in advance is required. You can use standard loads at any time and they will shoot reasonably well and blow out to the AI shape.
They have a steeper shoulder and less body taper than the standard to hold several grains more powder. Velocity is some higher and Ackley claimed that case life was longer.
Load data is different and you must have the correct AI loading dies to get the benefit.0 -
Yes, it is very much worth it. There are many rifles out there in this chambering. It was/is one of the most chambered rifles in the Ultra Light Arm's line up, from what I understand. It takes the venerable 257 Roberts to near 25-06 performance, using a short action.
There many pluses, and no negatives that I know of. You can shoot standard 275 Roberts in this chambering of a rifle, and have your new brass all formed when you eject it. Some even offer 257AI new brass...I believe it is available from Nosler now, along with the 280 AI.
Go for it!0 -
thanekerner,
As noted the round is fireformed in your chamber. There is a slight crush fit, .004" short, of the parent cartridge to get a good seat for fire-forming. You fire the parent cartridge in your chamber and the neck comes out .004" shorter, the shoulder becomes 40 deg. instead of 20, and the body at the shoulder moves out to .459" from .429". You gain about 8 gr. of total water capacity in the case. Which is only useable if you have a long enough barrel.
The short barreled .257AI is more of a waste than the standard .257 Rob. It's when you get longer barrels that can use all the gas produced by the cartridge that you begin to see the real advantages. I use a 26" barrel on my .257 Rob and I get great velocity. The .257 AI could use a 24" or a longer barrel. I had a 21" barrel in .257 AI, and while it was very accurate, it couldn't attain better velocities than my standard .257 with the long barrel.
A caveat to this is you could go to a tighter twist and shoot heavier custom bullets and burn the powder efficiently in a shorter barrel.
The theory behind the improved case life is taking the taper out of the body. When the round fires the more perpendicular case walls grip the chamber walls at max pressure. Thereby reducing bolt thrust. This is true to a point but you can still flatten out and blow primers. I had in a number of cases been able to get 'swipe' on my case heads from extreme pressure. But, using standard pressures in the AI case will help with case life. Of course with the longer barrel it will help with velocities.
Bottom line is go for it if it has a 24" or longer barrel. Otherwise it's a waste.0 -
quote:Originally posted by tsr1965
Yes, it is very much worth it. There are many rifles out there in this chambering. It was/is one of the most chambered rifles in the Ultra Light Arm's line up, from what I understand. It takes the venerable 257 Roberts to near 25-06 performance, using a short action.
There many pluses, and no negatives that I know of. You can shoot standard 275 Roberts in this chambering of a rifle, and have your new brass all formed when you eject it. Some even offer 257AI new brass...I believe it is available from Nosler now, along with the 280 AI.
Go for it!
If you intend to reload, which is pretty much a given with the various AI cartridges. AI full length sizeing die(s) are required, unless your rifle/loads enable you to get away with just neck sizeing. The problem with this is that if you didn't get the original full length sizeing die that was provided with the rifle, problems will ensue. Reloading with standard dies will shorten your brass life greatly. To my knowledge the AI cartridges don't have standardized SAMMI dimensions. If you don't have a custom die made for your rifles specific chamber dimensions, you are also going to have problems with the fired brass life expectancy.0 -
Most of the info you need has been covered in earlier posts. I have a 1903 Springfield sporterized and converted to 257 Roberts AI. It is one of the best shooting rifles I own. Fire forming is easy, just shoot standard 257 Roberts in the AI and the brass forms to your chamber. Don't know that it kills any deader than the standard 257 Roberts but it is fun to use. Just want to follow up a bit on Rufe-Snow's comment about dies. There is more than one variant of the 257 AI; at least two different shoulder angles and possibly more. I ordered dies from RCBS (40 degree shoulder) and these were the right ones for my rifle. However, have seen other 257 Roberts "improved" brass with a different shoulder angle and that brass would not chamber in my rifle. Just something to be aware of when you buy an "improved" 257 especially if its on a sporterized military platform and you have no way to know who did the work. Probably best to buy dies and gun together if possible. 0 -
Parker Ackley determined that a case with very little body taper, and a sharp shoulder angle (35* or 40*) would produce more pressure/vel with less powder than a magnum.
The AI cartridges blow out the case taper as well as change the shoulder angle to 35* or more prevalently 40*. This causes an increase in powder volumne, and increased pressure as it takes the plasma more resistance to pass by a sharp shoulder, thus increasing MV. Cases also last longer with these sharper shoulder angles.
I have 3 Ackley chamberings and am a big fan.
as a side note to your question, the 257AI will mimick a 25-06 using less powder. a win-win situation with barrel wear and powder cost0 -
Some visuals
From the 30-30 family of cartridges, some wildcat and ackley improved versions
These are what the factory cartridges look like
And finaly a direct compairison, (not your roberts however) a 22-250 and a 22-250 Ackley Improved side by side.0 -
Thank you all for those posts. That tells a lot in only a few short sentences. I really don't know if going with an AI is worth it. I'm just out for targets, and a 257 round is already a fast-flyer, especially in 75 gr. I'll probably simply stick with a normal round. 0 -
thanekerner,
Welcome to the Gunbroker Forums!
This is in three parts.
Part 1, from Mike Bellm's observations about P.O. Ackley:
"Ackley" can best be described as a mindset, not just the straight wall, sharp shoulder design he made famous.
Ackley is an analytical, realistic way of getting into problems and finding solutions. It is a love of rifled sporting firearms and the guys who use them.
It is also an attitude that looks at the "common wisdom" put out by the shooting industry with a jaundiced eye and challenges it when it does not stand up to the light of day.
P.O. laid the foundation for me to work from, but most importantly, he taught me to think through things. It was not a matter of learning to do things just one way. P.O. was a chronic experimenter, continually challenging all the accepted "truths" that turned out to have flawed logic that did not hold up in the real world. That is what has pretty much set my course. It also tends to set one at odds with the rest of those in the gun trade that don't agree with what I can easily demonstrate when it flies in the face of "common wisdom" or accepted practice."
Part 2:
"Ackley Improved.
What does it mean? Is it a reformed cartridge case?
I'm looking at a Mauser in .257 Roberts Ackley Improved.
Is it worth it to go with an AI?
Are AI cases easy/hard to find?
Can I fire normal rounds in an AI gun?"
Most of this has been answered in good detail but I wanted to add a little bit:
Buyers, sellers and some posters often confuse the terms 'Ackley Improved' and simply 'Improved' when writing or reading descriptions.
Ackley Improved should be a reference to the cartridges that P.O. Ackley himself created with the 40 degree shoulder and the blown out (straightened) case body. Since he did not actually 'improve' all of the cartridges available or the new cartridges obviously, the term has been used and applied frequently when trying to describe the case shape as opposed to the actual cartridges worked on by Ackley. The 40 degree shoulder angle and straighter case body mark the delineation of the other 'improved' cartridges which use different shoulder angles and lesser degrees of straightening the case body. Examples are the RCBS versions of 'improved' cases of which some use the 28 degree shoulder. A factory version of a more radical nature is the 7x61 S&H Super which uses a 44 degree shoulder on a belted case.
The beauty of the true Ackley Improved cartridges is that the factory ammunition can be safely fireformed in a rifle with the proper Ackley chamber. There are a few factory cases that are in the Ackley configuration, one being the .280 Ackley Improved ammunition and cases available through Nosler. Others are available through custom reloading companies.
Part 3:
Often the emphasis for having an Ackley Improved chamber is the increase in velocity. This can be true in some situations but not all, across the board.
Velocity increase is not always the best reason for an Ackley chamber. Two points in favor of the Ackley chambers are that the cases rarely need trimming after the first fireforming in the improved chamber. This is a real advantage when cases with the older, longer tapered shoulders need to be worked on. Examples are the .220 Swift and the Hornet or .30-30 cartridges. Yes, I know Lisle Kilbourn was the originator of the K-Hornet.
The reloader using Improved cases, benefits from a greater capacity certainly but it's the greater selection of appropriate powders that can be used in these cases which makes them desirable. The improved shoulder often increases the efficiency of those powders. This is too often overlooked by the reloader. Sometimes a slower, often cooler burning powder is appropriate to the load which can aid in barrel life.
Best.0
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