Berdan to 209 shotgun primer

[schatzperson]

Hi everyone,
I would like to know if it is at all possible to effectively and safely convert Berdan primed 7.5x55 Swiss cases to take 209 shotshell primers.
Before anyone jumps in to say that its not worth bothering with Berdan, let me put you in the picture of where I am at:
I live on a small island in Europe, Malta. Reloading stuff is not plentyfull and everything costs way too much.
Norma Boxer 7.5x55 brass will set me back about 140 Euro for 100 cases; Thats 178$.....crazy!!!

I can get once fired, Swiss, Berdan brass at a good price;
I was wondering if I could get away with not going into the trouble of swaging the twin primer holes and reaming the pocket to convert to Boxer, and go for a 209 shotshell primer conversion.
I have not looked at the mechanics closely, but it seems to me that this will involve decapping and drilling plus counterboring, one operation).
My concern is one of ballistics:
Using a 209 shotshell primer, will I upset the internal ballistics of a rifle cartridge like a 7.5x55 Swiss ?

My fear is that I might generate faster burn times and a different pressure/time curve than is expected in a rifle load, and possibly cause a dangerous situation.

Perhaps somebody here has tried this or somehow come across this issue.
I thank any help in advance.

 

[schatzperson]

I wonder if the the increased surface area of the shotshell primer,over a Berdan type) will expose the base of the primer to too much pressure and cause setback?
This is another worry that came to mind apart from my initial question of 209 primer being too powerfull and PERHAPS causing the powder to ignite too fast.
Anybody out try this before?

Vincent

 

[jb]

the 209 is probly not as strong as large rifle primer? i would think a 209 is made for max presure of 1400 lead units presure not 60,000 copper units presure. i think it would be much safer to mill off the anvel and drill a center flash hole as small as posable to deprime and use a large rifle primer. start 25% under max charge. with a 25-06 and 60gr H870 with 100gr bullet i went from .078 to .125 flash hole and the speed didn't change. 2800 to 2850 fps and no presure signs. other powders may act differently. this is why you need to start low. i hope this may help. jb

 

[Travelor]

Have you looked into reloading using berdan primers?

Even though boxer primed cases are avaiable, I reload 7.62x54 Russian using berdan primers. I use a small punch that I turned to fit the neck of the case tightly. I fill the fired case full of water and use the punch with a small hammer to hydraulically remove the primer. After drying, a small brass rod and a flat surface allows me to tap the new primer in. Works great.

This would be a much better solution that shotgun primers IF berdan primers are available to you.

 

[schatzperson]

Hmmm things are looking a little clearer now;
The shotgun primer, as Jb pointed out will not be such a good idea;
Even if a 209 primer can withstand the extra pressure of a rifle round, if I bore the case through in order to fit and seat a 209 primer, I would be exposing the primer to many times the area than would normally be the case if a regular flash hole is used.

Having said all this, I have not found any Berdan primers in shops here; I guess I could buy them online but am not sure if primers can be simply posted. I will check this out since once fired Swiss Berdan brass is more or less easy to obtain.

In case you guys are wondering what this interest is all about:
I have just bought, along with a Sig 550, a few Swiss rifles, a Sig AMT in 308, a Tanner target rifle and an Stgw 57 both in 7.5x55. The AMT and Stgw 57 are in unusually pristine condition.
Call me crazy, for wanting to shoot such fine pieces, but I dont think I can restrain myself enough !

One other question, since I have no experience with 7.5x55: I can get Redding, RCBS and Hornady dies for this caliber, any idea which is "best" suited for my requirements?

Thanks!

 

[FALPhil]

One other question, since I have no experience with 7.5x55: I can get Redding, RCBS and Hornady dies for this caliber, any idea which is "best" suited for my requirements?

I handload for 7.5x55. There is some controversy as to which dies best suit later chambers. The Schmidt-Rubin rifles had one chamber spec and the K-31 and StG57 had a "tighter" chamber spec. IMO, the Redding dies will work your brass less. However, people using the Lee Deluxe die set report high satisfaction.

Another thing to be aware of is that the profile of the projectile in GP-11 ammo, standard issue for the Swiss army when they were using it, was especially suited for short leades. The consequence of this is that for most high BC bullets made in America, you will have to seat them deeper into the case with a shorter OAL in order to not jamb the bullet into the lands when chambering. I think a bullet with a tangent ogive, like the A-Max would probably work better than a secant ogive. I solved the problem by dropping a weight class, i.e., 150-155 grain.

THe 7.5x55 is a fantastic cartridge, and I miss the days of cheap GP-11 ammo. It would pretty much shoot as good as factory match ammo.

 

[StevenDzupin]

Look Here !!

http://www.dave-cushman.net/shot/berdan_supplies_dimensions.html

RCBS makes a workable removal tool!


Regards,

Steve

 

[StevenDzupin]

From someone on the " Firing Line "!

"I reload the GP11 for the K31 rifle, I get my Berdans from http://www.brassmanbrass.com/ They are not on his website, you have to call to order.
My method of depriming is to take a 5/16" bolt about 4" long and cut off the threaded part. Its a hair too thick to fit in a fired case, so put it in a drill motor and sand it down until it just fits.
A 1/2" socket 3/8"drive is just right to hold the case. So, just dip the case in a pan of water, set it in the socket, put in the bolt and give it a whack with a small hammer. The primer pops out into the socket drive area.
This takes longer to describe than to do, and only a few drops of water come out. Dump the rest of the water out of the case and set out to dry. I can deprime these almost as fast as I can the Boxers, but you still have to resize and let them dry."


Regards,

Steve

 

[StevenDzupin]

And last but not least, this might be a work around !

"Here's another alternative I read about on another board for the 7.5 Swiss:
7.5 Swiss brass can be made from Boxer primed 284 winchester cases just by running them through a full-length die with a good tapered neck expander like the Lee dies have. Use Imperial sizing die wax on both the case and the case neck.

The 284 case is 2.170 and the 7.5 Swiss is 2.185 so the reformed cases witll have a slightly shorter neck by less than 1/16th of an inch. The rim will also be slightly smaller but it will work."

Regards,

Steve