Fireforming

[nvbroncrider]

Got a couple questions while fireforming. First I know you can fire a standard round in an ackley chamber but my question is do you have to change powders and loads? And second do you have to seat the bullets to touch the lands. I understand the reason for doing this is reliability.

 

[JD338]

As a rule of thumb, a max load of the parent cartridge is a starting load for the AI.
Example- 280 rem 140 gr 57.0 grs RL 19 is a max load but a starting load in the 280 AI.

If the AI is correctly chambered, the parent acrtridge will have a slight crush fit on the neck/shoulder junction of the case. This is where it will head space so you do not have to seat bullets into the lands.

JD338

 

[nvbroncrider]

Thanks Jim that's what I thought just wanted to double check cause it didn't make much sense to me reading the nosler manual. Bought some brass and my dies for my AI still no action. Gonna have the whole thing before the action.

 

[JD338]

nv

What AI are you building?

JD338

 

[nvbroncrider]

280AI on a 700 then a 338-06AI or a 35 AI on a Pre-64.

 

[Woodycreek]

This is a good article on the 243AI and fire-forming. I started fire-forming using max parent loads and switched to the cream of wheat. It saves bullets, powder, wear on the barrel, no copper fouling, and can do it in the backyard instead of going to the range.


.243 Ackley Improved--More Velocity, Less Case Stretch
by Bob Blaine, Sinclair International

Parker Ackley reluctantly developed the .243 Ackley Improved ("AI"). Ackley finally gave in to his customers' requests to develop the .243 AI. He had always felt that the .243 Winchester was already an improved configuration, but he did say that the best thing to be gained by improving the .243 Winchester was to substantially reduce the case-stretching problems. The .243 Winchester parent case has always stretched brass, almost as bad as the Swift. Even though you get more velocity with the improved .243, I've also found that the improved version gives a bit more throat life than the parent case does.

The .243 AI delivers more velocity by virtue of enhanced case capacity--roughly five grains more H20 capacity than a standard .243 Winchester. The .243 AI has a water capacity of approximately 57 to 58 grains, compared to 52-53 grains for the standard .243 Winchester.

Fire-Forming
As always, fire-forming is done by one of two methods. Most of you will fire form the brass with loaded .243 Winchester. Ackley always said to use factory loads, or reload equivalent ammo to have a "snappy" load to form the case out properly. You never want to use a reduced load to form with, since you need the pressure to form properly. If your rifle is chambered properly, you should feel a slight amount of resistance as you close the bolt on a new piece of brass. If you do not get this "feel", you may need to seat the bullets out to .010" to .015" into the lands to make sure that the base of the case stays in solid contact with the bolt face. The fire-forming method I have been using more lately employs medium burn-rate pistol powders and Cream of Wheat. I will start by loading about 10 grains of SR4756 or Unique into the case, and then I fill the case up to the body shoulder junction with Cream of Wheat. I will then take a large pinch of polyester filler, which can be found at any fabric supply store, or sewing department, such as at Wal-Mart. I will then take the pinch of polyester and load it into the case so that it fills up the shoulder area of the case effectively making sure that the filler is held securely over the powder for fire-forming. During the fire-forming, I like to dry brush with a nylon bore brush every 10 to 15 rounds. This removes any loose debris from filler that has accumulated. [Editors Note: Do NOT seat a bullet using this "Cream of Wheat" method. You can cap the case with a bit of wax to keep everything in place. However, Bob finds the wax is not necessary if the polyester filler is placed securely.]

Recommended Loads
I'm often asked, "what gunpowder do you recommend"? I generally recommend medium-slow or slow burn-rate powders for the .243 Ackley. I have found, with my rifle, that H414 is pretty much my first choice for use in the .243 AI. H414 tends to give me great accuracy, with good velocity. Saying this, I have tried many other propellants and have found the following powders to be worth looking at for your needs: AA-2700, H414, H4350, VV N150, VV N550, VV N160, VV N560, RL19, H4831sc, and VV N165, to name a few of the powders that I have tested over the years.

Different Reamers, Different "Improveds"
One thing that you need to watch for is what version of the .243 Improved that you have. This depends, for the most part, on whose reamer you will be using for the chambering of your barrel. It is easy to determine if your .243 Improved is the .243 Ackley Improved, or the .243 Winchester Improved. If you have the .243 Ackley Improved, the shoulder-body section will measure .460" dia. at this point. If you have the .243 Winchester Improved, the shoulder-body section will measure .455" diameter at this point. Both cartridges have the 40-degree shoulder. I have used both versions and found that you can use any data developed for either version interchangeably.

The .243 Ackley Improved is one of the best long range varmint rounds going, and can add some extra punch for your light big game rifle as well. One would be hard pressed to ignore a cartridge as versatile as the .243 Ackley Improved.

 

[bullet]

You picked some good cartridges to build customs on, sounds like fun.

 

[JD338]

280AI on a 700 then a 338-06AI or a 35 AI on a Pre-64.

nv,

Very cool! 8)
Let me know if I can help you with 280 AI loads.

JD338

 

[nvbroncrider]

Get my Pre-64 action next week still got to find my 700. One barrel is on order so maybe end of March.

 

[onesonek]

I can't add alot here, with the exception that I have found those on the 06 case and 08 case can't be quite different depending on how tight the finished chamber is.
With the 06 case, an AI gives a fair amount of volume gain, not so much with the 08 family. I bring this up, as I haven't had issues using max parent loads in the 06 family, but in my .243 AI, the chamber is tightly spec'd, and max parent loads are still too warm in my chamber with certain powders. With the 06 family, depending on the chamber, I have run anywhere from 3 to 5 grs. on avg., over book max for the parent.
Also, you might want to get neck reamers. While AI rounds don't grow as much in length, brass still flows forward albeit, less than a case with more body taper. This flow in an AI case mostly stops at the shoulder neck juncture, creating what is known as the infamous " neck donut". This really should or needs to be reamed out. If not you can run the risk of forcing the shoulder back slightly when running the expander ball past it during sizing. Also, if not reamed, forcing the EB past it swage's the brass back into the case, leaving a slight lip. This restricts and or changes the gas flow. Now i don't know how much that hurts anything directly, other than messing with pressure consistency, which has to affect accuracy in my mind. I ream after every firing, but not sure it is absolutely necessary after the first two. One might be ok with reaming after every other firing, after the first 2 when brass flow stabilizes somewhat (not totally).
Now I know some guys that don't ream at all, that's their choice and get by. But I can't help but think how it affects pressure and accuracy. I want that neck shoulder transition smooth as ossible without disruption myself.

 

[bullet]

I can't add alot here, with the exception that I have found those on the 06 case and 08 case can't be quite different depending on how tight the finished chamber is.
With the 06 case, an AI gives a fair amount of volume gain, not so much with the 08 family. I bring this up, as I haven't had issues using max parent loads in the 06 family, but in my .243 AI, the chamber is tightly spec'd, and max parent loads are still too warm in my chamber with certain powders. With the 06 family, depending on the chamber, I have run anywhere from 3 to 5 grs. on avg., over book max for the parent.
Also, you might want to get neck reamers. While AI rounds don't grow as much in length, brass still flows forward albeit, less than a case with more body taper. This flow in an AI case mostly stops at the shoulder neck juncture, creating what is known as the infamous " neck donut". This really should or needs to be reamed out. If not you can run the risk of forcing the shoulder back slightly when running the expander ball past it during sizing. Also, if not reamed, forcing the EB past it swage's the brass back into the case, leaving a slight lip. This restricts and or changes the gas flow. Now i don't know how much that hurts anything directly, other than messing with pressure consistency, which has to affect accuracy in my mind. I ream after every firing, but not sure it is absolutely necessary after the first two. One might be ok with reaming after every other firing, after the first 2 when brass flow stabilizes somewhat (not totally).
Now I know some guys that don't ream at all, that's their choice and get by. But I can't help but think how it affects pressure and accuracy. I want that neck shoulder transition smooth as ossible without disruption myself.

Very well stated onesonek, I agree with your observations about the 06 cases as apposed to the 08 cases for Ackley IMproved cartridges. Also, I think you are right on about reaming necks, at least every other time not only to hold pressures consistently and having good accuracy, but also the consistent lower Deviation I have experienced in my 30-06 Ackely Improved is testimony to consistent accuracy when ream the necks at least every other loading. Good stuff, thanks for bring it up.