OzFclass

GDay Tim
I finished fire forming a new bunch of cases earlier this year, started of using 29.5gr 2208 with a 107 smk seating into the lands probably 30th. key to it was using soft Fed. 205 primers and plenty of neck tension. Came out well but same as you I lost 2 out of the first 50, they looked exactly like that picture of yours. Upped charge to 30.0 gr 2208, and finished off the last 50 cases, better shoulders with these ones. I believe your and my problems are as mentioned above a fault in the original case somehow.
Mine shot the same as your while fire forming, pity it, and me haven't shot as good since !!
I seemed to get consistent fire form lengths with this method as well.

Dave how are cases hydraulically formed? Could you please explain how it is done and what is needed.
Steve.

Have to agree with Footsore, it would be great to learn more about the hydraulic form.

With regard to the false shoulder, my understanding was it emerged in an effort to stop erratic ignition of the primer if the case moved forward a tad when guys were fire-forming with tissue to hold powder back without a projectile seated in the neck. Its an erratic ignition problem, in that the cases do not get an effective burn to form properly. Some people might be thinking the case moves forward and so is not in the right position to form the shoulder properly rather than an explosive problem. The false shoulder method which enlarges the neck with a mandrel by about .02" has the top third (roughly reduced) to correct neck size. The fat section on the neck allows the case to be crushed in place. Rather than use tissue, others are now placing a projectile in the neck and may or may not jam it. So in effect the case is set up from shoulder/neck junction rather than the bore line in the throat.

Can't say I have had an erratic ignition problem using the traditional hard jam and fast burning powder with warm load. You only have to look at your primers afterwards to notice any variance. Its easy to size a neck small or tight enough to resist the case moving forward using the right collet. Particularly if you anneal the case, then undersize the neck and allow the bullet to expand the neck. That area of the neck beneath the projectile once the bullet is jammed in place is smaller than bullet diameter and sufficient to resist the pin much in the same way an expanded neck resists movement. The pin is also limited by its protrusion and resistant the surface area of the primer skin. If there was no force limiting the case going forward the pin at worst will give misfire but mostly erratic ignition. But relative to the surface area of the neck gripping the bullet with it jammed, the primer skin has little resistance.

Matt P wrote:Brad
I have never been able to get enough neck tension to stop the case moving forward when the pin strikes the primer.
Matt P

This is particularly true with the shallow leads so many of us use. I believe in a false shoulder & jammed bullets to have proper fireformed brass in the case of the Dasher. Contrary to popular belief I fireform with the same load or a slightly lighter load than that which I end up using, I do not anneal & have formed thousands of cases without the loss of a single case in the forming, that is not to say that it is not a good idea to anneal, I just do not have the time & have not found the need to do so. Has worked for me, others may have different outcomes.
Keith H.

Keith, whatever works works, but the jam length sorts that shallow leed.

I use 4-5 thou tension and a .030 jam. Most come out within .002-.003 of each other at the datum. Out of my last 3 batches ive lost
2-3 cases from those same shoulder splits.

Interesting. Now I have an annealer set up I will give the false shoulder method a go, but like I said- havent had any troubles as long as the charge is high enough and I have a decent jam and neck tension. A quick trim after the second fireforming and they are good to go.

Here is a link to 6BR that shows a short video using Hornady hydraulic case forming dies.

http://bulletin.accurateshooter.com/?s= ... mit=Search

Also word is on the street that 6 Dasher brass (new manufactured) might be available here in the States around mid summer 2015.

Also we just shipped a ammunition pressure test barrel to one of the powder manufacturers a couple of weeks ago and they just started using it early last week and are very impressed with the results it's giving them and they said they haven't even started shooting the heavy bullets yet. It's a 1-8 twist, 30" finish length barrel. Our chamber reamer spec.

Later, Frank
Bartlein Barrels

Frank Green wrote:Here is a link to 6BR that shows a short video using Hornady hydraulic case forming dies.

http://bulletin.accurateshooter.com/?s= ... mit=Search

Thanks for the link Frank. So that is how it's done. Very interesting.

Steve

frank

thanks for that link and information.

that is what i was alluding too.

however, for anyone contemplating hydraulic forming, i would offer the suggestion that the force is applied axially (as per a pile driver) and not via the swing of a hammer.

using a hammer, the arc of swing wastes energy, it is not applied axially consistently and may end up bending the piston.

the actual force required for a one blow form is quite surprising.

also just my opinion but, i would suggest that the most consistent case froming dimensions will be achieved with 1 blow of the the force (ie high impulse is most important).

it is easier to work or shape the brass when new in the factory annealed condition. my experience is that having to apply more than 1 force impact is not as successful as the brass will work harden after the first impact and the dimensions will vary.

i have found that soluble oil works well as a fluid.

brass quality, thickness and hardness and the degree of case shape change (internal and external) all have to be taken into consideration and allowed for to achieve satisfactory forming procedures.

hydraulic forming may not be quite as successful as a slave barrel/chamber but it does exhibit many advantages and once set up, many cases can be formed to a consistent quality and headspace tolerance.

over a long period of time, i have used this procedure to form 22BR, 30x57 improved, 280 improved, 7x57 improved,6x47 lapua and 7mm06 Improved (7x63 improved).







as shown, based on a shortened 280 improved body die (although FLS dies work just as well)
this set up has formed hundreds of 280 improved,7x57 improved and 7x63 improved cases.

it is adjustable for whatever case and case length that is required

cheers
dave

Dave you have really hit the mark. This method would save wear on those precious barrels while forming cases and you don't have to get a fire-form barrel. While I have never done this, Herb Mc made me up an hydraulic primer remover from an old Omark barrel stub and a truck engine valve to remove those tricky Berdan primers on military brass and I can tell you the hammer often bounced and I wore a lot of water. Your method solves this problem. Just might have a crack at making a die and stem for the press after I finish all the jobs the wife has lined up for me.

Thanks Frank for the video link, it sure will open the minds of a few shooters.

Brad, I used to work with a guy who worked for the Super Cartridge company, who informed me that a case goes through many drawings and annealing at each stage of the production process. This was confirmed by a reference I later got hold of for punches and dies but was first published in 1931. Edit: The previous temperature range I gave for the 10 or annealings in case manufacture was for larger shells having re-read the old reference. I can not give the exact figures because the reference skipped from .303 and 30-06 to large cases; and so I have deleted it because it would less for our gear given the thinner wall section of the case.

However, the annealing before and after tapering is relevant and this is pertinent to fire-forming cases and to annealing the neck for stabilizing neck tension and taking out the case memory at about 600-650f for 8 seconds.

The reference, Punches, Dies and Tools for Manufacturing in Presses says, that the tapering happens in two operations with annealing to avoid risk of cracking . Before tapering annealing is at a higher temperature. After tapering at a lower temperature before the case is then driven home into the die chamber.

What I do to form a custom case prior to fire-forming is use Tempilaq at 450F halfway down the case to indicate and prevent heat at the shoulder from weakening the walls and the base of the case. You don't want to overheat the brass or soften it too much. At the mouth where the case wall is thinner, you don't want you to go over 650F, and at the mid point on the shoulder where the heat is applied you are probably looking at 600f. The heat tends to increase a bit as you respond to the stopwatch before moving the flame away which is based on your Tempilaq melts. If you use Tempilaq 650F, then use a water quench. I don't quench in water, as I go with 600F, some do. I don't use a broad flame to heat too slowly. A very hot blue flame brings the neck/shoulder up to temperature quickly without letting heat spread down too far to the mid point. See diagram below. My thinking is the more you alter the case, if you are thinking of designing your own, the more annealing you need. I'm sure annealing would assist the hydraulic method of forming cases.

With so many annealing steps in case manufacture, its not surprising cases even within batches in manufacture alter and would probably explain variance in headspace after fire-forming. For practical time constraints it may be easier to cull the ones that don't survive the re-form. If you do anneal, cases need to be work hardened a tad with a Sinclair neck expander as this reduces the time it takes for cases to settle with subsequent firings.



David

williada

mate, i should have mentioned that from the beginning i never intended to place the die in a press for hydraulic forming and am still not in favour of it.

knowing the magnitude of the forces involved and the difficulty of ensuring they are applied axially and consistently, i don't wish to risk damaging a press.

i much prefer to do the procedure on a solid footing and if i make a mistake (through poor alignment etc) (touch wood this has not happened yet!!!) all that is at risk is the die set up shown and maybe the odd toe or two!!.

BTW for anyone who attends the 2015 SCC, if there is any interest i will demonstrate the procedure at the range or at the narromine tourist park.

cheers
dave

Dave, I hear where you are coming from. But I have a heavy hydraulic press in the workshop that I just might have to wipe a few cobwebs off and adapt and make a heavy die with a reamer. Like your practical approach. However giving this a bit more thought, that sharp blow and pile driver approach might be the way to go. The idea of dropping a guided set weight will get due consideration or may be a pneumatic hammer drill approach. You have really got me thinking Dave. Thanks for your contribution. Cheers, David.

Dave- when is the 2015 SCC? I would have thought you would have a perfectly good fireforming barrel now with that dud one you were talking about!

g'day brad

the dates for the 2015 SCC will be:-

thursday/friday 25th-26th june -practise/sighting in/load development days.

4 target match SCC - saturday /sunday 27th-28th June.

mediation,counselling, kiss and cuddles etc, late sunday afternoon, probably just before, during and after the bbq.

yeah, you are not wrong with that dud barrel, but before i worked out is was a dud, i did spend numerous hours, sorting, selecting, hydraulically forming, preparing, cleaning, neck turning, final fireforming around 80 lapua cases (originals not the blue box stuff) for it.

and not to mention mumerous trips to the paddock to run in the barrel etc?????

what a waste of time, effort and $$$$ all of that was!!!!

all the best to all for christmas and the new year.

cheers
dave