Alliant 2400 for fire forming 243AI ?

Gregg C

Gregg C

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Got some LC brass I've necked down to 243W, and now want to put an Ackley Imp shoulder on it, using Cream of Wheat. I have some 2400 left over from my 44Mag days. It's the only pistol powder I have. Is it too energetic, do you all think?
I tried just loading a 243W load in them, but was splitting the necks at the neck / shoulder junction. 50% loss, in fact. Hence, COW method idea.
Thanks
 
For starters, anneal the brass. That should fix the splits. Be sure that the case necks arent too thick for your chamber since necking from 30 to 24 cal is quite a jump and will thicken the necks. I form a lot of ai but never used 2400. I've always used 10-15 gr if red dot or unique when I used COW. Watch how the shoulders are forming and increase the carge as needed to get fully formed shoulders. I also found that using coffee made less of a mess in the barrel and cases since it is already burnt/roasted. After the COW is burned it left a lot of burnt material stuck in the shoulder that had to be removed with a pick. Ackley recommended a "snappy" load of fast burning powder.
 
I turn the necks at 308 or 7/08, then neck down to 243 AI. I anneal after necking down. The results are amazing. I do not know that I have ever lost a case in thousands of cases. The 243 AI is my long range p. dog round and I fire form with 47-47.5g of Win 760 with a 70g ballistic tip using CCI 250.

ON the 260 AI, I use 14-15g of Bullseye and cream of wheat to fire form. You have to use a bent paper clip to run around the inside of the 40* Shoulder angle because unburnt cream of wheat will often get lodged in this area decreasing the case capacity sending pressure higher on a regular load.

Brass that has been fire formed more than once in the parent case will often split upon fire forming in the AI. Cases that have excessive headspace in the AI will split. This is why it is beneficial to turn necks at the larger caliber, then set headspace when you neck down, as you can create a false shoulder to headspace on.
 
VinceMule said:
I turn the necks at 308 or 7/08, then neck down to 243 AI. I anneal after necking down. The results are amazing. I do not know that I have ever lost a case in thousands of cases. The 243 AI is my long range p. dog round and I fire form with 47-47.5g of Win 760 with a 70g ballistic tip using CCI 250.

ON the 260 AI, I use 14-15g of Bullseye and cream of wheat to fire form. You have to use a bent paper clip to run around the inside of the 40* Shoulder angle because unburnt cream of wheat will often get lodged in this area decreasing the case capacity sending pressure higher on a regular load.

Brass that has been fire formed more than once in the parent case will often split upon fire forming in the AI. Cases that have excessive headspace in the AI will split. This is why it is beneficial to turn necks at the larger caliber, then set headspace when you neck down, as you can create a false shoulder to headspace on.
Click to expand...
Just to be certain we are on the same page, is that suggested load for Lake City brass?
I annealed before necking down. Going to anneal again, and try again with a bullet down the tube.
Hate to admit it, but I got a lazy streak!
 
Seabeeken said:
For starters, anneal the brass. That should fix the splits. Be sure that the case necks arent too thick for your chamber since necking from 30 to 24 cal is quite a jump and will thicken the necks. I form a lot of ai but never used 2400. I've always used 10-15 gr if red dot or unique when I used COW. Watch how the shoulders are forming and increase the carge as needed to get fully formed shoulders. I also found that using coffee made less of a mess in the barrel and cases since it is already burnt/roasted. After the COW is burned it left a lot of burnt material stuck in the shoulder that had to be removed with a pick. Ackley recommended a "snappy" load of fast burning powder.
Click to expand...
Thats a great idea, using coffee! Two of my favorite odors, coffee, and gunpowder!! Whatever moved you to try that?
 
How much clearance is considered minimum in the chamber to loaded neck ? The LC brass has .002, Federal has .005 to .006.
LC necks are roughly .002in thicker than the Federal cases. Looks as tho neck turning is in my future.
 
Work up the fire form loads with Bullseye just like you would any other load to get the desired results. You will find a perfect fire form somewhere between 14-15g, work up in .2g increments.\

The load I gave you with 70g is very accurate and the 70g Ballistic tips are a great deer bullet using lung shots, you will be surprised at the penetration.

Note: low powered fire form loads will split cases everytime.
 
Gregg C said:
Just curious, why is this a bad idea?
Click to expand...
Neck turning required.
Neck short.
Bolt was always a crush fit.
I watched the new GI ammo get fired in many M14 rifles on semi-auto.

Loaded & tested in Rem 40xb, 243 Win.

At the time, was thinking a neck with less slop in the chamber would be more accurate. Was not.

Be careful with Bullseye Powder, it can detonate. Edit- Tested by Homeland Security and ATF agents.https://discover.dtic.mil/



Good luck with your project, hope it works for you loading AI.
 
Last edited:
Thanks for chiming in, folks. I think I'm just going to buy premium brass. Lapua, Alpha, Peterson, or such. In spite of that, I'm gearing up to turn necks, also. Thanks again.
 

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