Fireforming

Having my GS chamber a 260AI for me and don't want to use up components fireforming. Is there a proven method of using cream of corn?

Eric H said:

Having my GS chamber a 260AI for me and don't want to use up components fireforming. Is there a proven method of using cream of corn?

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I used to use cream of wheat but it left a lot of burnt debris in the case shoulders and bore so I switched to coffee. Its already burnt and smells good when fired. I started with 10 gr IMR red topped off with coffee to the neck and a piece of toilet paper to hold it in place and fire. Use this to form both my 250ai and 12 gr for my 257 and 7x57 ai's
10 gr unique or red dot should work for you. use more if shoulders dont fill out completely. wear hearing protection, they are loud

Seabeeken said:

I used to use cream of wheat but it left a lot of burnt debris in the case shoulders and bore so I switched to coffee. Its already burnt and smells good when fired. I started with 10 gr IMR red topped off with coffee to the neck and a piece of toilet paper to hold it in place and fire. Use this to form both my 250ai and 12 gr for my 257 and 7x57 ai's
10 gr unique or red dot should work for you. use more if shoulders dont fill out completely. wear hearing protection, they are loud

Click to expand...

Thanks

My method:
Thread 'COW Fireforming recipe'
https://www.longrangehunting.com/threads/cow-fireforming-recipe.303247/

Why do people continue to do things like a cave man? Especially with the cost of things these days.

I have wild cats and AI's. Some of them were very over bore which will lead to very short barrel life. So I thought that will go out with a chronograph and bench rest fire form my cases with the same amount of powder intended for my new larger AI. I also took a long some reloaded AI's for a comparison. They chrono almost exactly the same within the ES. After dispelling the corn meal myth I've actually taken shells hunting that I was fireforming as I blasted away at critters.

Just skip the baby steps!

Eric H said:

Having my GS chamber a 260AI for me and don't want to use up components fireforming. Is there a proven method of using cream of corn?

Click to expand...

I have done COW and hydraulic forming dies, but you would need at least one firing of the chamber at full load. Ackley designed his cartridges to fire the parent cartridge, load it and have fun with it. In my .270 AI, I ended up with accuracy load for .270 Win and .270 AI.

budlight said:

Why do people continue to do things like a cave man? Especially with the cost of things these days.

I have wild cats and AI's. Some of them were very over bore which will lead to very short barrel life. So I thought that will go out with a chronograph and bench rest fire form my cases with the same amount of powder intended for my new larger AI. I also took a long some reloaded AI's for a comparison. They chrono almost exactly the same within the ES. After dispelling the corn meal myth I've actually taken shells hunting that I was fireforming as I blasted away at critters.

Just skip the baby steps!

Click to expand...

I tried that in my 243AI with a -.5gr full load and didn't group well. Trying not to waste components. Every gun is different but if you have about 100 .264 bullets I'll gladly fireform with those.

I fire form 6mm AI from 6mm Rem or 7X57 (neck down). I quit using COW & now I use dried coffee grounds. Most of the Starbx coffee grounds are used as mulch for wifey's potted flower plants without drying but enough remain for fire forming. A pinch of fuzzy fiber fill from an old trashed Walmart pillow is used between powder & coffee and tamped down with a .25 wood dowel then TP to hold everything in place on top of coffee.

The last 6mm AI session included fire forming with real bullets in my 10 twist rifle. The load was 45.0 SW4350 & 87 H hpbt. Groups were close to 3 in the same hole at 100. Slight crush fit after F/L size, new brass, with shortened shell holder. Velocities were estimated as being good.

I also F/F .280 Rem form .270 Win. This involves necking up .270W brass to .30 cal. I use a Hornady .30 elliptical expander in a 7mm WSM die but only to expand .27 neck to .30. The next step is to F/L size with a .280 Rem F/L die forming a 2nd shoulder for head space - slight crush fit. 12.5 grains of AA#9 works good.

Caution must be used when F/Fing with pistol powder - excessive pressures can occur.

I also do F/Fing in my garage. I use a 5 foot length of 4 inch white PVC pipe capped at one end. The pipe is strapped down into a step ladder with bungee cords. Front half of rifle goes into pipe. Real loud, wear ear protection. Much smoke, ventilate. Use lens caps on scope. Lots of debris in pipe. Dirty, clean chamber after each pop. Your neighbors & side walkers might hear this & be upset - I only do 10 or so pops a day, saves a 40 mile round trip to range. I also use my .22 Ram Set to drive RS nails thru 2X4's into concrete so the neighbors think I am involved in some productive home improvement project.

I've fire formed thousands of AI cases using various methods. COW is my preferred method because of reduced cost, barrel wear and the ability to form cases without a trip to the range. One thing I've learned to avoid excessive case stretch during forming is to first establish a false shoulder by expanding the case neck up one caliber and then resizing the neck back to desired caliber. It is an extra step, but well worth it given the price of brass today. As for powder, almost any fast pistol or shotgun powder will do. I used green dot in a charge weight approximately 1/3 of a normal powder charge for the parent cartridge. After topping off with COW, I seal the case with Ivory bar soap.

I just load and go now. Tried the COW method and didn't quite get the full formed shoulders for my 6.5 Sherman which moves a lot of brass.

For my 22-250 AI, I loaded a near max charge and formed 100 pieces over a couple of days shooting prairie dogs.

Just work up an accurate FF load like any other and go shoot them. I have even hunted with FF loads.

I built a 22/204 last build, chambered up a shot out 223 barrel to do fire forming, used a stash of primers that were pushed out of brass but un fired, std 223 load behind some 55 grn fmj, formed a false shoulder by necking up and took them to the range and just fired the lot off. Came home and changed barrels. I have a 6mm dasher barrel that is shot out which gets used a lot for forming as well

Like @lancetkenyon said, work a load up for fire forming. I've shot fire forming loads out of several 260ai barrels that were impressive. I wouldn't call it wasting components

FF loads can be every bit as precise as the final product.
Starting out with consistent brass yields good results as usual