Factory Ammo in an Ackley Improved Chamber

S

Stats Shooter

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P.O. Ackley, from what I have read, intended for an improved chamber to fire the standard cartridge in that chamber. In this way, brass can be harvested as improved brass to then be load developed for the new improved cartridge.

I have mentioned in other posts, I have a new 6mm/.244 Remington Ackley Improved rifle and have yet to fire a round through it, and am acquiring components. Unfortunately, the only brass in stock is Hornady which I do not like. Moreover, I hate to spend time handloading ammo just to make brass. I like Winchester brass because it's tough, volumous, and after match prep and culling it's as good as premium brass.
So, my thought is to buy some Winchester super X ammo, go out and zero the scope, familiarize myself with the rifle, and get everything adjusted properly while I fireform AI brass.

So, before I go buy $200 worth of ammo, I just want one last thread of opinions. Otherwise I can get some
new Winchester brass off gunbroker and load it myself with some test bullets.

I would prefer to do the factory ammo thing if it works properly, but if not, I don't want to waste time, money, and barrel life NOT getting good fireformed brass.

Thanks
 
Go for it.....Factory ammo will shoot fine in your AI. Also, just to clarify something, you are not wasting ammo if you fire form new brass. An accurate FF load will most likely be just as accurate if not more so when you up the powder charge for the formed case. Some brass will require more than one firing to blow the shoulder out nice and straight too.

Enjoy your new rifle. You'll love it.
 
My AI's, I've always used new brass. I use same powder/bullets that going in the AI. One of my AI's I shoot PD forming brass.

My 243AI and I used lapua brass and shoulders formed after first firing. Your not going to find ammo with VLD that your going to shoot in that rifle.

I've never build one without brass so my answer is based on that but I could of purchased factory and that's always been option with Ackley's.
 
My AI's, I've always used new brass. I use same powder/bullets that going in the AI. One of my AI's I shoot PD forming brass.

My 243AI and I used lapua brass and shoulders formed after first firing. Your not going to find ammo with VLD that your going to shoot in that rifle.
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Ok Roper....I bought 200 pieces of win brass, 6mm. I have redding 6mmAI dies with neck bushing and micrometer seat. I'm going to begin load development while Fire forming brass. Do I need some 6mm Remington standard dies then too? I assume so. I was thinking of just getting a cheap Lee set of standard dies to seat bullets and ensure case necks are properly rounded.
 
I have at least 16 forming dies, if I had one forming die it would be the 308 W forming die, if I had two forming dies the second die would be a 243 forming die.

If I wanted to know the options when deciding what case to use I would use the RCBS Special Order Catalog. I understand providing a link is a waste of my time but; 6mm Remington cases can be formed from 30/06 cases.

Fire forming improved cases shortens the case, I have built rifles with improved chambers that shortened the case .045" form forming to firing, by changing methods and techniques I managed to start with a case that was .051" too long because I am the fan of bullet hold.

One nice thing about the Ackely Improved is the neck gets longer and the case body gets larger in diameter.

F. Guffey
 
It is a general idea that an 'improved' cartridge chamber would be safe to use the non-improved ammunition in. That was one of the things that set the standard for the 'improved' round.

Of course there are exceptions, and not every rifle chamber will perform equally, so the thing to do is get advice from experienced owners and do research through other documents.

An example of a variance that I remember is that a case neck was supposed to be enlarged by expanding it beyond factory size and then sized down far enough to allow the neck to enter but be stopped by the bump created when the thing was expanded up. It was for a rimless cartridge. It straightened the case, moved the shoulder forward a bit, shortened the neck. It wouldn't really have been a good idea to do it without that bump on the shoulder to hold the base firmly against the bolt face.

I guess that my point is that an improved cartridge is not the same thing as a completely rechambered case. It's slightly modified and it usually can fire the parent factory ammunition.
 
"Go for it.....Factory ammo will shoot fine in your AI"

I would qualify that statement. "Factory ammo will shoot fine in A PROPERLY CUT AI chamber."
I got wankered on a "custom AI chamber" job years ago. The 257 AI chamber is too long to use factory ammo and requires creative loading to produce usable brass.
 
The improved cartridge was best served with rimmed or flanged cartridges that didn't headspace on the shoulder. A discrepancy between chamber and die that left a few hundredths of an inch of unsupported area at the base would cause stretching at the base. A rim would prevent headspace problems and the case would balloon a bit to fill empty space. This obviously could bring about its own issues, but it wouldn't ordinarily result in a case head separation.

Imo, a visit to a Smith with loaded and fired rounds is a good idea. It will tell you how closely the dies match the chamber and help determine if it is safe to use in general.
 
So here's another question,

I
Fire forming improved cases shortens the case, I have built rifles with improved chambers that shortened the case .045" form forming to firing, by changing methods and techniques I managed to start with a case that was .051" too long because I am the fan of bullet hold.
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Is the improved cartridge supposed to be trimmed to the same length as the standard cartridge?
 
While fireforming brass for my .22-250 AI I used a low powder charge and got 5/16" groups @ 100 yds. I use that as my varmint hunting/fireforming load. No wasted components or time.

I would, however, do my load development after fireforming.
 
Stats,

Your freshly fire formed brass will be shorter than SAAMI standard measurement. Brass has to flow from somewhere.
For my 7mm-08 AI i use PVRI Partisan casings. (PPU headstamp)
Even though my chamber is larger in diameter than the casing(AI) i full length size in std 7mm-08 dies.
I load a mid level powder charge, and enjoy a day at the range.

To save money, and for ready availability i use PPU 7mm Mauser casings and form my 257 Roberts. You can do same with 6mm Rem.
 
Your freshly fire formed brass will be shorter than SAAMI standard measurement. Brass has to flow from somewhere.
For my 7mm-08 AI i use PVRI Partisan casings. (PPU headstamp)
Even though my chamber is larger in diameter than the casing(AI) i full length size in std 7mm-08 dies.
I load a mid level powder charge, and enjoy a day at the range.
Click to expand...

That's my plan....I'm not going to bother trimming the new brass. Just run it through sizing die, load a low-medium pressure load and mess around with seating depth while Fire forming brass and get comfortable with the rifle. Then once I have fired it all once, I will trim it, turn the necks, uniform the pockets, deburr the flash holes, and cull the ones that don't make the cut.
 
"Go for it.....Factory ammo will shoot fine in your AI"

I would qualify that statement. "Factory ammo will shoot fine in A PROPERLY CUT AI chamber."
I got wankered on a "custom AI chamber" job years ago. The 257 AI chamber is too long to use factory ammo and requires creative loading to produce usable brass.
Click to expand...
Must not have been the Ackley Improved chamber. The AI chamber uses factory brass.
 
I have several AI chambered barrels and all shoot factory ammo perfectly. In fact they all shoot it plenty good enough to just use factory.

I have however worked up loads for them just so I can justify having them built.:D
 
Then once I have fired it all once, I will trim it,
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In the perfect world; first the neck starts to form when the factory round is chambered. At the same time part of the shoulder is formed because:eek: that is what is meant by saying the case head spaces on part of the shoulder because the neck of the factory round is shorter than the neck on the Ackley Improved chamber

One more time; I form and fire form cases, when I form most cases the case shortens from the end of the neck to the case head. when I fire the form case the rest of the shoulder and case body expand and form to the chamber. All of this forming is caused by case expansion, when the case expands the neck is pulled back; When doing all of this forming and fire forming I have never seen a neck move forward.

Neck move forward: The neck would move forward if the shoulder moved forward, the shoulder moving forward is a very popular belief among reloaders; if my shoulder moves forward I have a case that has the beginning of case head separation.

One more time; I have formed and fire formed cases that have shortened .045"; I know, reloaders insist something has to get longer, the length of the case will get longer from the end of the neck to the case head if the shoulder of the case moves forward when fired.

F. Guffey
 
I have to agree with F. Guffey. I have a 22-250AI and when I fire form brass from standard 22-250 my neck always come up short have never got to max length of 1.9079. I have shot them short and for a while they shot 5 shot groups in the .3s and .4s. Now the last time I shot it had shotgun pattern??
 
I've had a few things that required fire-forming, including something that required forming a false shoulder in the neck to set headspace first (can't remember what that was...?).

Most of those rifles shot better with fire-forming loads than anything tested later.
My theory, like that of many other wildcatters and some prominent writers, is that the extra room in the chamber and malleability of the brass helps smooth the pressure curve as the case blows out.

I'm also a believer in using full power loads for fire-forming. There is arguably some truth in the idea that hotter loads might cause the brass to stretch more in certain areas that others, and that case failure is potentially more likely. But I've never seen it, and I don't really care. One way or another, the case has to get formed. And if you use light loads, the result is not always a fully-formed piece of brass. Shoulders may be soft and incompletely formed. Case bodies might not blow out quite as far as necessary. Etc..

Anyway...
If the chamber seems to be cut correctly, I wouldn't hesitate to fire-form with factory ammo. More than likely, it'll shoot like a dream while doing so.
 
Neck move forward: The neck would move forward if the shoulder moved forward, the shoulder moving forward is a very popular belief among reloaders; if my shoulder moves forward I have a case that has the beginning of case head separation.

One more time; I have formed and fire formed cases that have shortened .045"; I know, reloaders insist something has to get longer, the length of the case will get longer from the end of the neck to the case head if the shoulder of the case moves forward when fired.
Click to expand...

I get it, the neck will shorten upon case forming. But I will still want a uniform neck length and I can only assume that the cases, after forming, will be slightly different from one another. So, I will still need to trim.
 
I get it, the neck will shorten upon case forming.
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No matter what method and or technique I use the case shortens from the end of the neck to the case head.

The neck on the 30/06 case is shorter than the neck on the 30/06 Ackley Improved, or put another way the Ackely improved neck is longer than the standard 30/06 neck.

I know, reloaders claim they move the shoulder back and they can move the shoulder forward, I understand that sounds impressive but when forming, sizing and firing my shoulders do not move. I understand how difficult it must be to understand when I say the length of my case from the shoulder to the case head increases without moving the shoulder, added to that when I say the distance from the shoulder to the case head increases the case shortens from the end of the neck to the case head; point? I would suggest you measure the length of the case, there is no harm but I would suggest you try to figure why the case got shorter when forming and or firing.

F. Guffey
 
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