Fire-Forming with MoM or COW? (Malt-O-Mean or Cream of Wheat) 17 Mach IV cases?

[TheCZKid]

Well, I'm getting a 17 Mach IV soon (I hope soon) and have been making cases for it, from Lake City. Same as I make my Vartarg brass, but with more work involved! Anyway, I was thinking, after I get these formed, maybe I should fireform them, so they'll shoot better sooner. I'll have about 700 new cases, it would be nice to have them shoot nicely early on.

Never done it before, and have read that people make Ackley Improved cased this way. The 17 Mach IV is basically same as 17 Fireball in case volume (about 18 grains). Sounds like people figure out a certain amount of pistol powder, then use Malt-O-Meal or Cream of Wheat, and fill the case pretty high, then stuff pillow stuffing (Dacron, looks like a cotton ball) into the necks, and BOOM!

My question is, would it make enough of a difference in accuracy to do this? And, what powder charge would you guys suggest? I have lot of Bullseye, and a pound of Unique I'll probably never use.

Plus, have a lot of small pistol primers, thought those would be easier to sacrifice than small rifle primers, for sure.

And, lastly, I was wondering, what does this mix of pistol powder, COW and Dacron fluff do to the interior of a nice 17 caliber Lilja barrel? Will it leave a bunch of burnt plastic residue from the Dacron, or is that stuff just shot out and not ignite?

Your experience appreciated. Normal powder load of a 17M4 is about 18 grains of rifle powder, so Unique load??

 

[6MMsteve]

not worth the trouble and mess, bullet load n shoot...it's just a big mess in my opinion I use to do it till I figured it's easier to just shoot them to fireform....unless it's a have to case...I have a 260AI I just shoot them to fireform lot easier...unless u just want to tinker

 

[Ron Gorski]

Well, I'm getting a 17 Mach IV soon (I hope soon) and have been making cases for it, from Lake City. Same as I make my Vartarg brass, but with more work involved! Anyway, I was thinking, after I get these formed, maybe I should fireform them, so they'll shoot better sooner. I'll have about 700 new cases, it would be nice to have them shoot nicely early on.

Never done it before, and have read that people make Ackley Improved cased this way. The 17 Mach IV is basically same as 17 Fireball in case volume (about 18 grains). Sounds like people figure out a certain amount of pistol powder, then use Malt-O-Meal or Cream of Wheat, and fill the case pretty high, then stuff pillow stuffing (Dacron, looks like a cotton ball) into the necks, and BOOM!

My question is, would it make enough of a difference in accuracy to do this? And, what powder charge would you guys suggest? I have lot of Bullseye, and a pound of Unique I'll probably never use.

Plus, have a lot of small pistol primers, thought those would be easier to sacrifice than small rifle primers, for sure.

And, lastly, I was wondering, what does this mix of pistol powder, COW and Dacron fluff do to the interior of a nice 17 caliber Lilja barrel? Will it leave a bunch of burnt plastic residue from the Dacron, or is that stuff just shot out and not ignite?

Your experience appreciated. Normal powder load of a 17M4 is about 18 grains of rifle powder, so Unique load??

If you use COW, use the uncooked variety. I have found that it doesn't do any damage to the barrel.
I have used cleaning patches to fill the necks.

 

[Oso]

I think it makes sense if you want to form a large batch of brass… you save on components and barrel life. For the price of 1# of powder and a canister of grits you save the price of bullets and 2# of powder if doing direct fireforming. I did a large batch of 223AI for a couple of rifles. I used 9.5gr Bullseye and then filled remainder of case with grits. For your purposes start at 6.0gr of either Titegroup or Bullseye. If you wanted to refine the charge weight then load up 3 cases for each charge weight starting at 5.0gr and increase by 0.5 gr increments up to 8.0gr.

Two things to keep in mind is that you’ll want to keep your powder positioned toward base of cartridge, which is a little more challenging with ball powder. I dropped my powder into case and then inserted a piece of a wad to keep powder separate from the grits. I then poured in the grits and used other half of wad to stuff in neck and tamp down. This process is easy and using a powder funnel is essential to managing down risk of spilled grits. Use a small dowel of brass rod to help position and tamp down the pieces of wading. Also, you might put your loading block inside a container (Tupperware, shoebox lid, baking pan, etc) to help control the inevitable spillage.

Last suggestion is to bring out a couple of cans of compressed air (keyboard cleaner). Since the shoulders aren’t yet formed it is common to get some debris (burnt grits) around outside of neck and shoulder area. Periodically give a short blast of compressed air into your chamber to blow out any debris that might have fallen loose as the fired case was extracted.

 

[Ackman]

Well, I'm getting a 17 Mach IV soon (I hope soon) and have been making cases for it, from Lake City. Same as I make my Vartarg brass, but with more work involved! Anyway, I was thinking, after I get these formed, maybe I should fireform them, so they'll shoot better sooner. I'll have about 700 new cases, it would be nice to have them shoot nicely early on.

Never done it before, and have read that people make Ackley Improved cased this way. The 17 Mach IV is basically same as 17 Fireball in case volume (about 18 grains). Sounds like people figure out a certain amount of pistol powder, then use Malt-O-Meal or Cream of Wheat, and fill the case pretty high, then stuff pillow stuffing (Dacron, looks like a cotton ball) into the necks, and BOOM!

My question is, would it make enough of a difference in accuracy to do this? And, what powder charge would you guys suggest? I have lot of Bullseye, and a pound of Unique I'll probably never use.

Plus, have a lot of small pistol primers, thought those would be easier to sacrifice than small rifle primers, for sure.

And, lastly, I was wondering, what does this mix of pistol powder, COW and Dacron fluff do to the interior of a nice 17 caliber Lilja barrel? Will it leave a bunch of burnt plastic residue from the Dacron, or is that stuff just shot out and not ignite?

Your experience appreciated. Normal powder load of a 17M4 is about 18 grains of rifle powder, so Unique load??

Fireforming!!! Some people make it more complicated than it is. Don't waste your plrimers or powder, or time messing with fillers. Use bullets. For AI cases, start at the max book load for the std cartridge and go up - watching pressure signs - untill you find the best accuracy......just like you would with any other chambering. I've done many thousands of cases this way - 1000 for almost every barrel, all in the field. The 17MIV has less reloading book info but really is just a just an improved version of a necked down 221 fireball. My fireform load was18.0 / H335, behind a 25gr bullet.Very nicely accurate, .Used it on a ton of groundsquirrels, pd's, and also rockchucks. For fireforming I'd recommend a powder from the reloading manual in that burning rate range starting low for the MIV and going up. Find best accuracy, load up a whole slew of them, and go shoot stuff. Bullets group a lot better than COW. *** In my barrel, AA2230 has been best in formed cases with 23 and 25gr. bullets.

 

[butchlambert]

Kinda what I thought, a lot of different opinions. Not saying any are wrong. If you don't have a separate fire forming barrel, don't use bullets for your first fireform. I do have fire forming barrels. Regardless of case capacity I use at least 1/2 cartridge case of Bullseye and Play Doh, wax, or? to seal the neck. Now with a fire forming barrel and unlimited cheap bullets I might do it that way.
I'm doing a 222 Remington Magnum Ackley at this time. I have an old Remington 600 barrel in 222. I will cut about .080" off of it and run the 222 mag ai reamer. That will be my fireform barrel. I'm doing a 30BR for our club shoots and I found one of my old 30BR barrel stubs. It is head spaced, but only 4" in total length. I think it will work.

 

[L.Sherm]

You would be surprised at how accurate fireforming loads shoot, do load work up just like with formed loads and go shoot some sage rats.

 

[butchlambert]

You would be surprised at how accurate fireforming loads shoot, do load work up just like with formed loads and go shoot some sage rats.

They don't seem to be very accurate forming wildcats though in my experience.

 

[L.Sherm]

They don't seem to be very accurate forming wildcats though in my experience.

Maybe not BR accuracy Butch but shooting sage rats all mine shoot plenty accurate enough for a intended purposes, here's an example with my 20BRA

 

[TheCZKid]

Looks like my initial formed brass will be pretty close to final form, so it might be a supreme waste of time to fire form the cases, but thought I'd ask. Here's 4 cases in their "final" formed state, before shooting, I'm sure they're close enough to be Sage Rat accurate, like my new 20 Vartarg cases are. It's more fun shooting at something than shooting COW!

 

[butchlambert]

Maybe not BR accuracy Butch but shooting sage rats all mine shoot plenty accurate enough for a intended purposes, here's an example with my 20BRA

Cases that are almost the size of your chamber will likely shoot well. I'm speaking of some of my wildcats that are blown out a very great amount.

 

[TheCZKid]

I was just looking to square off the shoulder to body and neck areas, wasn't sure that would make any real practical improvement or not. Likely not enough.

When I first got my 20 Vartarg, and had a lot of newly formed / never shot cases, I developed my final loads with some brass I shot, but finalized my load with what shot well with both new and 1x or 2x shot cases, as most of my shooting initially was going to be all never-shot cases, hundreds of them.

 

[Gabe22BR]

Use them cheapazz hornady bullets- At’s why they there !!!

 

[L.Sherm]

Cases that are almost the size of your chamber will likely shoot well. I'm speaking of some of my wildcats that are blown out a very great amount.

On his Mach IV when you use FB brass its not changing much and since he's making his own you can get the brass as good new brass. Here's a 19 Badger forming made from 30 carbine.
The one in the bullseye is not one of the 3

 

[L.Sherm]

The 17 MachIV is really nothing more than the 20VT necked down to 17 cal.
I believe from the base of the case to the shoulder there the same length and shoulder angle

 

[butchlambert]

On his Mach IV when you use FB brass its not changing much and since he's making his own you can get the brass as good new brass. Here's a 19 Badger forming made from 30 carbine.
The one in the bullseye is not one of the 3

I think I said if you are moving the brass only slightly, just work up your load. I'm not familiar with his chosen round, but now wonder why this was even brought up.

 

[Oso]

COW / 80% Fire-Forming Method has its use. For a large batch of brass it has meaningful cost savings in components with not a huge amount of additional time. Another meaningful benefit is saved barrel life. On a chilli day (mid 40’s) I could fire a cartridge as fast as I could single load without the barrel changing temperature… so 500-750 cases within 2.5 hours. If your impatient then you can even do this in a covered trash can in your garage.

By all means if you have time, resources, or cartridge that only needs minor blowout to achieve final form then forego COW and simply load and shoot. If I had a prairie dog colony then I’m in Sherm’s camp of load and go plinking. If it’s +95F and you are killing paper then I might reconsider my option with AC… garage, trash can, and ear muffs.

There are many ways to skin a cat. Sometimes you have to try everything at least once. That said, .17 cal bullets are cheap and shooting gum balls off golf tees is fun… you can always roll back to 50 yards and still have fun forming cases

 

[L.Sherm]

I think I said if you are moving the brass only slightly, just work up your load. I'm not familiar with his chosen round, but now wonder why this was even brought up.

I think fireforming is a subject term to different people, you can ' fireform" new production brass, to an AI or like 6 BR to Dasher there is a difference and how you go about it.
I used to do the cream of wheat method 20 years ago on my 17 pee wee untill I got tired of it and wondered just how well it would shoot sage rats with then one day I just started working on a load with the bullet. 010 past touch and never looked back.
At that time I had to make my own brass out of 30 carbine.
It was a great learning experience.

 

[Hoser]

I recently did a batch of Lapua 221 that I turned into 17 MachIV. I tried twice fired loads compared to fireforming loads.

Basically the same. Only 15-20 fps slower. Not enough difference to matter on a prairie dog or a fox.

 

[rayh]

I think fireforming is a subject term to different people, you can ' fireform" new production brass, to an AI or like 6 BR to Dasher there is a difference and how you go about it.
I used to do the cream of wheat method 20 years ago on my 17 pee wee untill I got tired of it and wondered just how well it would shoot sage rats with then one day I just started working on a load with the bullet. 010 past touch and never looked back.
At that time I had to make my own brass out of 30 carbine.
It was a great learning experience.

I agree, load and go shoot something. But if you would like to fire form first, try to find a book by Maj George Nonte on Cartridge Conversions. I loaned mine and never got it back. In it he has a formula using Bullseye and a wad of tissue. The formula works well. I took it one step and used a car muffler with off set in and out pipes. Made a plug for the intake, taped my barrel to prevent scratching. I just put the muzzle into the snug fitted plug and pulled the trigger. It worked well enough my anti gun neighbor would work in her yard . I'd wave and pulled the trigger, she never knew. I was doing a 17 Ack Hornet.