243 Win Ackley Improved primers.

[mkopmani]

I just thought of something that I failed to mention - I always lube the case with Imperial Sizing Wax prior to fire forming. This ensures that the chamber doesn't grab the case. This may be what is happening - maybe try lubing the case and see if it goes away.

 

[Ackley Man]

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

Definately caused by setting back the bullet. Jam the bullet 0.020.

 

[Ackley Man]

FIRE FORMING WITHOUT BULLET AND WITHOUT CREAM OF WHEAT
PER SPEEDY GONZALEZ



FILL ONE OF THE CASES THAT YOU WISH TO FIREFORM ALL THE WAY TO THE TOP

OF THE NECK WITH ALLIANT 2400 POWDER. WEIGH THE FULL CASE POWDER

CHARGE. CALCULATE WHAT 40% OF THE POWDER WEIGHT IS.

USING RIFLE PRIMERS CHARGE A FEW CASES WITH THE 40% WEIGHT. FILL CASE

WITH A COTTON BALL. YOU CAN ALSO SEAL THE CASE MOUTH WITH BEE'S WAX.

A 12" X 12" SHEET CAN BE PURCHASED FROM HOBBY LOBBY. LUBE THE CASES

BEFORE FIRING.





IF CASES ARE NOT COMPLETELY FORMED WITH 40% BUMP LOAD UP TO 45 OR

50%. MAXIMUM SHOULD BE 60%.

 

[Justice1327]

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.

I have over 2500 on my 243 AI. I shoot one050108 and I use H1000 or RL 26. The slower burning powder doesn't cause the throat to erode nearly as much.