243 Win Ackley Improved primers.

[victorc]

This 243 Winchester AI project is my first with a wildcat requiring cartridges to be fire formed from another cartridge. In this case the 243 Winchester. Today was the first to begin the process.

Each shot produced what seems to be a perfect Ackley Improved cartridge. The only thing that seemed odd is the primers backed out of the pocket a bit. I don't know what this means. The fired cartridge was easy to extract from the chamber. There are no extractor marks on the base, nor is the primer flat or cratered. Any ideas what might be causing this, and is there reason for concern? My load is listed below.
* New Lapua 243 Win brass
* Federal 210 primers
* 47.0 grains H450 powder
* Hornady 90 grain ELD-X bullet
* COAL = 2.70

 

[laker]

Is there any slight resistance when chambering a 243 case before fireforming? Are you jamming bullet into lands when fireforming?

 

[victorc]

None at all. Bullet off the lands by 2/1000.

 

[laker]

Try jamming the bullet into the lands and fireform one

 

[GLTaylor]

Fireforming is easy and simple. If you have a correct AI chamber, the factory round should fit with a slight crush fit. This generally holds the case against the bolt face during fireforming.
You rarely fireform fully with one firing. It usually takes 2 to complete the process. The primer protruding means the case wasn't fully compressed between the shoulder and bolt face.
The easiest way to fireform is back off the load a couple of grains and seat the bullet firmly into the lands. This holds everything in place during fireforming.

 

[slikmrc]

Firing pin is driving the case forward and the case is grabbing the chamber and causing the gap between case and bolt face. I would only neck size case for the next firing. You should let the smith that did the chamber know what is happening. Chamber may be a bit long.

 

[victorc]

This 243 Winchester AI project is my first with a wildcat requiring cartridges to be fire formed from another cartridge. In this case the 243 Winchester. Today was the first to begin the process.

Each shot produced what seems to be a perfect Ackley Improved cartridge. The only thing that seemed odd is the primers backed out of the pocket a bit. I don't know what this means. The fired cartridge was easy to extract from the chamber. There are no extractor marks on the base, nor is the primer flat or cratered. Any ideas what might be causing this, and is there reason for concern? My load is listed below.
* New Lapua 243 Win brass
* Federal 210 primers
* 47.0 grains H450 powder
* Hornady 90 grain ELD-X bullet
* COAL = 2.70
View attachment 242525
View attachment 242526View attachment 242527

Got the message. Understood and appreciated.

 

[Tiny Tim]

Your load looks about right. You could try a faster burning powder but that would only mask the problem. What you have going on is good in the sense that it has identified an incorrect headspace problem, whether caused by the chambering process or reloading. At least your load wasn't high enough to stretch the brass by driving the head back against the bolt and thinning it above the web. You can get some measurements and contact your smith, do as others suggest and back off your load and jam the bullet into the lands (the easiest), or neck up a size and neck size back down to create a false shoulder with the correct headspace. You have options. Its a great cartridge. I'm loving mine.

 

[can1010]

A+ on what Tiny Tim said and don't bump the shoulders on the cases you already fired because they are not fully formed, if you do it will start the case head separation problem.
my preferred method is the false shoulder method. it seems to be the most reliable for proper case forming

 

[Tiny Tim]

A+ on what Tiny Tim said and don't bump the shoulders on the cases you already fired because they are not fully formed, if you do it will start the case head separation problem.
my preferred method is the false shoulder method. it seems to be the most reliable for proper case forming

I agree, the false shoulder method I'd best and after working the brass and fire forming twice, he should probably annealing as well.

 

[victorc]

I now have once fire formed Lapua brass for my 243 Winchester AI. It has been suggested above it takes two firings to get the brass to it's correct dimensions. I have the Redding Deluxe Die Set and am planning to only use the neck sizing die on the first batch of AI loads. Am I okay to start load development with the once fire formed brass, or will brass dimensions change significantly enough that I should wait until after the second firing?

 

[Seabeeken]

When headspacing ackley improved rounds you should use Manson headspace gauges as they are made to have the .004" crush fit. H-450 is a slow burning powder and may not be building enough pressure. Ackley recommended a "snappy" load. As already said, the case gripped the chamber and expanded and didnt set back against the bolt face after being driven forward by the firing pin. Had it done so, it likely would have had a case head separation which may still happen on the next firing. I learned this while forming 250ai cases.

 

[mkopmani]

I have a 243 Ackley Improved. I fire form my cases without bullets, using 15.0gr Hogden Clays, corn grits as filler to the neck, then 1/8th piece of toilet paper to prevent spillage. This gently fire forms the case. Then I annual and load a lower charge with bullet to crisper the neck. I believe your primer backing out is a headspace issue. Try fire forming without a bullet and see if that resolves it.

 

[QuietTexan]

Am I okay to start load development with the once fire formed brass, or will brass dimensions change significantly enough that I should wait until after the second firing?

If you wanted to start now you'll probably end up close and can tweak your way to a final load. Find your windows and adjust back into them.

Personally I would wait, but I don't have enough brass to put significant wear on the barrel while forming. I try to find something decent for fireforming, use it until the cases are grown, then do my "real" load workup. I don't view that as wasting barrel life because the forming loads are usually pretty good, and really what's the harm in using up even 10-15% of barrel life with the forming loads if it makes the last 75% better? I'm viewing my 243 AI as a 1,000 round barrel, anything past that is probably just luck.