QUESTION-Fireforming Cases-SAFELY

  • 536 Views
  • Last Post 08 August 2020
mashburn posted this 24 July 2020

Hello to all out there,

First of all my reason for this article is to learn how to safely fireform cases. About 22 years ago I started playing around with .17 rifles. My first project was a .17 Mashburn, which is a necked down and blown out with a 40 Degree shoulder with a .171 long neck, just the same length as the bullet diameter .218 Bee case. I have made these from. .218 Bee  25-20  32-20. Right now I will stick with the Bee cases. During my first attempts I would form the case and then anneal. I had been told that you could load bullets after annealing and fire and eject a perfect case. It don't work folks .My next approach was to stick about 3 grains of a fast burning powder in and then I had poured melted bullet lube in a little pan to a depth of about 3/16 inch. After the lube solidified I would take it in my left hand, turn it upside down and take the powder charged case and stick the neck up in the lube and twist and remove. This made a lube bullet blank. Having heard stories of reduced loads causing explosions, I put the rifle in a secure fixture and pulled the trigger with a string. RESULT-a perfect case. tHAT WAS THE ONLY TIME i EVER TIED IT UP. The 25-20 and 32-20 cases that I converted required more annealing or the would split. Of course that Cartridge require a lot more form die work that the Bee requires. I had no enlarged primer pockets or any thing. I have shot these cases many a time and am still shooting them.

Now here is the problem I encountered. I built a Ackley Improved .223 rifle and being a perfectionist I wanted to fireform them before I loaded so I had real .223 AI cases. I was going to follow the same procedures as for the little .17. I can't remember what powder I used on the Bee, I'm positive it was a fast burning pistol powder. When I started the .223 fire forming I was out of that particular powder so I started looking through my powders and thought  WW 231 will work (not sure but almost positive it was ww231)  I think I used 8 or 9 grs. I fired a lot of these through a strong 700 Remington Varminter and I mean a lot. Here is the surprise-when I went to load these cases about half or maybe more of them had loosened primer pockets, I mean so loose that the primers would fall out. i HAVE FIRE FORMED WIILD CAT CASES WITH REAL BULLETS AND HAD GOOD LUCK NEVER LOST A CASE, i JUST USED FAIRLY MODEST CHARGES OF THE POWDER i INTENDED TO LOAD WITH. WHAT HAPPENED?I need to form some cases for my new toy a /17 Ackley Bee and am afraid to try it the old way. SOMEONE PLEASE HELP ME OUT.

Mashburn

I HAVE RECEIVED A LOT OF HELPFUL INFORMATION FROM OTHER MEMBERS. IN A DAY OR SO I'M GOING TO COMPILE ALL OF THIS INFORMATION AND POST A REPLY WITH MORE QUESTIONS. THANKS  AND  MY APPRECIATION TO ALL WHO HAVE RESPONDED. 

mASHBURN

David a. Cogburn

Attached Files

Order By: Standard | Newest | Votes
Rich/WIS posted this 24 July 2020

To much powder?  Wouldn't think just a lube plug would offer that much resistance to push pressures high enough to cause a problem.  My only experience with fire forming is 30/40 AI  with my usual light cast load, so not much help here.

Attached Files

45 2.1 posted this 24 July 2020

SOMEONE PLEASE HELP ME OUT

David........... fire forming methods differ with what you're trying to accomplish. Bottle neck cases are different than straight and rimmed, belted, rimless all differ. It really depends on how strong the case is versus it's shape. I've generated quite a few thousand myself in some strange calibers. For your 17 Ackley Bee, I would simply load a light charge of pistol powder (the correct charge is where it forms it properly and no more...trial and error) and stuff some paper toweling in the case to hold the powder and provide some resistance. Put case in rifle, hold rifle in air vertically (important with thinner cases) and pull trigger, inspect to see what you need to do if anything. Once you know how much to load, do the rest.

Attached Files

  • Liked by
  • Ross Smith
Little Debbie posted this 24 July 2020

I’ve always used the “Cream of Wheat” method. To wit: a small amount of Bullseye, then Cream of Wheat (I’ve used corn meal too) to fill to the neck, then a twist from a bar of soap as a plug. Then fire them outside! I tried this once indoors and it was spectacular (in a bad way). To do it properly a false shoulder needs to be formed so there is firm chambering to prevent case stretching. The two chamberings I’ve used this method in the most are the .338/06 and .17 Ackley Bee.

Pick your parent case carefully, in the .338/06 I’ve found that new Remington .35 Whelen is best. Neck down in .338/06 die to give firm chambering. 6 gr of bullseye, fill with cream of wheat to the neck, plug with soap, fire. Out will pop a perfect .338/06 case. Starting with .30/06 cases new or fired requires the to be necked up to .35, then false shoulder set with .338 die. Then the case needs to be annealed to get 100% good cases without some split shoulders. In the .17 Ackley Bee start with new W-W cases with 3 gr of Bullseye, cream of wheat and soap plug. Neck to create false shoulder, fire outside. Any other case or fired Bee cases need to be annealed after false should is set to prevent splitting. Annealing before your forming generally leads to shoulder collapse because the brass is too soft. Don’t rely on a rimmed case for headspace. I’ve had two .30/30 Ackley “improved”. Firing new cartridges or making cream of wheat forming rounds without setting a false shoulder made the web of .30/30 thin on the first firing. I’m my AI Model 94 (bought second hand cheap) the cases would nearly separate on first firing. In a Contender I rechambered the chamber was too long to set a crush fit with factory rounds and led to premature case failure. Setting a false shoulder by necking to .32 caliber first and then necking to .30 for the false shoulder solved this. The only AI chambers I’ve ever seen that worked properly to allow firing of factory ammunition to form was a.243AI that I chambered from a blank and a .223 AI that a gunsmith (a real good one) set back a thread or two before rechambering.

The amount of Bullseye I’ve listed is what worked safety for me. Start low and work up to where you get fully formed cases. I’m sure that any fast pistol powder will work. Bullseye is what I started with and have stuck to. Clean your barrel every 10 rounds, it gets unbelievably fouled with this stuff. An alternative is to set the false shoulder use a starting load with a jacketed bullet. This works but is a waste of powder and bullets and you need to be a range to do it.

Attached Files

ray h posted this 24 July 2020

Mr.Mashburn,  George Nonte had a book on Cartridge Conversions in which he gave a formula for using Bulleye vs the case capacity. It was the starting point.  He sealed the case mouth with tissue paper but your wax should be fine. I can't find my book to give you the formula but maybe someone has the book. I've formed , at first, a lot of cases using his procedure. I did make a snug fitted foam plug to put around the muzzle and stuck it into a car muffler when fire forming. The tissue would smoke smoke some but the ever watchful neighbors never figured out I was fire forming next door. In time I changed, since I had a set of Neil Jones forming bushings for 223 and PPC cases. I will expand my case nearly straight and then neck down giving me a near fire formed shoulder to head space off of. Without expanding the neck, on a lot of cases like the Hornet and Bee you don't have a lot of shoulder to head space off of going from 22 to 17 cal. I thought maybe the firing pin was driving the case forward allowing either splits at the shoulder or stretch above the web when fire formed. Jamming bullets didn't always help. It was after forming  1200 Squirrel cases and never losing one case in fire forming. In making the Squirrel you chop the Hornet case leaving a short straight wall case.  I annealed after all case prep. Back then the Ken Light annealer was the only one out there so that's what I use.  I don't remember about the Bee case but a Hornet is about 1.400 and after forming my way you'll end up with a case .035 to .045 shorter. Yet if you just neck down the Hornet case and fire form, it will still be around 1.400. I thought the extra .035-.045 length(over my forming method) came from stretching in the case body/ shoulder.  My way is a lot more work and for low number of brass maybe not worth the effort but it does work and has increased my case life some.. Good luck

Attached Files

GBertolet posted this 24 July 2020

I like the corn meal method. I have a 35 Whelen Imp, that I fireformed brass from 30-06, and 35 Whelen cases. I was advised by the rifle builder to use 10 gr Bullseye, fill case up to neck with cornmeal, put a piece of TP to keep the cornmeal in, and fire. I have fired them outside, and in the basement, into a stack of newspapers. It's messy, as I needed compressed air to blow out the cornmeal residue from the action and chamber every few shots. I don't think the full 10 gr of Bullseye is necessiary, probably half that amount would work fine also. The cases have their shoulders perfectly formed, and I don't remember ever losing a case from splits.

Addendum: for .223, or other small cases, a much lighter charge of Bullseye should be used, maybe 5 gr or less.

 

 

Attached Files

45 2.1 posted this 24 July 2020

Corn meal, COW, ground used tumbling media work OK with heavy wall cases, Don't be to forceful with the powder on light thin walled cases or the fire formed case will be missing everything from the shoulder forward when you unchamber it.

Attached Files

  • Liked by
  • JeffinNZ
Ross Smith posted this 25 July 2020

When I make my 308x1.625 cases from either 308 or 30-06 cases I just load them like they were finished cases. I had no luck with cow and pistol powder. But. When I squeeze down the 308 or 30-06 cases I'm down into the thicker part of the case walls. So I just anneal and go for it.

Attached Files

mashburn posted this 25 July 2020

Hello Rich/WIS,

It has me stumped. I think the WW231 has to be the cause. I've heard that it can get squirrley under certain conditions. I won't use it again.

Thanks for the response and information.

Mashburn

David a. Cogburn

Attached Files

mashburn posted this 25 July 2020

Hello 45 2.1,

Thanks for the response and information. The  forming with the .17 is BASICALLY  solved. My main question is what made the primer pockets enlarge so much when forming the .223 Ack. Imp. My idea is the WW231 powder. I've heard it can get squirely.

thanks again,

Mashburn

David a. Cogburn

Attached Files

mashburn posted this 25 July 2020

Hello Little Debbie,

Thanks for your response and the information you gave. I learned some from your post. My biggest question is what happened to make the primer pockets expand so much when fire forming the .223 Ack. Imp.? Was it the WW231.  After the .223 experience I'm nervous about fire forming anything. I know what you are talking about Improved chambers if done improperly. A lot of gunsmiths will try to run the chamber into an existing .223 chamber. If you stop the reamer a little short you will get a grove around the shoulder and if you cut the chamber to where a go gauge will chamber with lots of pressure, the chamber will be too deep and it will back primers. Like you said, a new blank or set the barrel back a thread or two.

Thanks again,

Mashburn

David a. Cogburn

Attached Files

mashburn posted this 25 July 2020

Hello ray h,

Thanks for your response and info. My main question is what caused the .223 primer pockets to enlarge so.

Thanks again,

Mashburn

David a. Cogburn

Attached Files

mashburn posted this 25 July 2020

Hello GBertolet,

Thanks for the response and information. It is very much appreciated.

Mashburn

David a. Cogburn

Attached Files

mashburn posted this 25 July 2020

Hello 45 2.1,

Thanks again,

Mashburn

David a. Cogburn

Attached Files

mashburn posted this 25 July 2020

Ross Smith,

Thanks for the response and information. I can see where the thick walls of the shortened case would take some thumping internally.

Mashburn

David a. Cogburn

Attached Files

  • Liked by
  • Ross Smith
45 2.1 posted this 25 July 2020

Hello 45 2.1,

Thanks for the response and information. The  forming with the .17 is BASICALLY  solved. My main question is what made the primer pockets enlarge so much when forming the .223 Ack. Imp. My idea is the WW231 powder. I've heard it can get squirely.

thanks again,

Mashburn

Too much pressure from too big a charge of really fast burning powder in too little of volume. That is the only way that happens.... you over loaded it. Depending on the burn rate, powders can get out of hand from using too little in to big a space or using too much in to little of a space. ALL POWDERS do that.....................

Attached Files

  • Liked by
  • MarkinEllensburg
mashburn posted this 25 July 2020

Hello 45 2.1,

Thanks again for responding, When I was forming the .223's I compared the volume of the .17 Mashburn to the volume of the .223 cases and tried to use the same percentage of powder to volume as I had used  in the .17's. I know it wasn't an over charge. I think my mistake was, I didn't use any filler and had too little powder in too large a space. The .223's that I formed with real bullets and normal loads formed with no problems(such as loose primer pockets) I really appreciate the time and effort that you have spent to give your help.

Mashburn

David a. Cogburn

Attached Files

shjoe posted this 27 July 2020

some time ago i bought an M95 straight pull steyr in original 8x50r chambering for a winter project. trimmed a few 7.62x54r cases to x50 and lightly annealed the shoulder area. unique, cow and a wax candle plug fired straight up. out popped an 8x50r fireformed case. they worked great with a "large diameter" 8mm 214gr cast bullet. never found loose primer pockets, yet. but i try and keep loads mild for the old girl. ray h, i like that muffler idea. i use to tape an empty plastic 2ltr soda bottle to the muzzle to tone things down for the neighbors. warmest regards, john

Attached Files

sluggo posted this 27 July 2020

I have a question on this subject. Can factory ammo be fired in a wildcat chamber to fire form a case. I have a 25-06 mashburn chambered rifle. Can I fire factory 25-06 rounds to fire form them? Would this be an unsafe practice?The rifle came with some ammo but it looks different than regular Remington 25-06. Thanks in advance.

Attached Files

TRKakaCatWhisperer posted this 27 July 2020

I often do that in other calibers.  (22 hornet in 22 K-hornet for example)  Additionally, my experience, they're just as accurate.

Attached Files

mashburn posted this 28 July 2020

Hello sluggo,

Cases like 25-06 improved, 30-30 improved,.223 Improved and etc. can be formed safely from factory ammunition, In the smaller calibers like K-Hornet or .218 Mashburn Bee will sometimes split the shoulder and neck.  I have some Wildcats that when I form the cases there is very little difference from the dimensions of a fired case, and these I simply load and fire. My .219 Donaldson Wasp is a good example of that. Now back to your 25-06 Mashburn. Are you sure it is a 25-06 Mashburn or possibly a 25-06 Ackley Improved. Here is something to be aware of. When a rimless case such as your 25-06 is converted one of two things must be done. If it is a new barrel blank , chambering the barrel and using a go guage works fine. For an existing barrel chambered in 25-06 the barrel must be removed from the action and the barrel has to be set back a thread. After this is done you can cut a good chamber. If you try to chamber and existing 25-06 chamber with out setting the barrel back there is one or two things that can happen If you cut the chamber so that the go gauge will enter you will have too much headspace and the rifle will back primers when fired. The second thing trying to keep this from happening is: stop the chamber where the go gauge will not let the bolt close and you will have a ridge in the shoulder of the case ,but it will not back primers. I have known of a lot of people who have sent rifles to supposedly gunsmiths and when they got them back they were Primer backers. I've straightened a few of these out when I had my shop open to the public .You can fire the rifle with out worrying with factory ammo. It either show a good chamber, or it will back primers slightly or it will have a ridge in the chamber but nothing dangerous if it is a good rifle. You don't have this problem with rimmed cases and that is why I try to base my wildcats on rimmed cartridges.

Your 25-06 is Mashburn is of great interest to me. Ken Campbell supplied me with two 25-06 Mashburn reamers and I have been putting off this project because I haven't found a set of chamber guages. If you do have a Mashburn 25-06 I would like to purchase a few cases from you that I can use them for gauges. The 25-06 seems to be getting popular again. I was quite surprised when I started seeing articles about them lately. Keep me posted on this project and remember I would like to purchase 3-4 cases. And please keep me posted on this project.

Thanks you very much for contacting me on this project,

Mashburn

David a. Cogburn

Attached Files

Show More Posts
Close