Primers

[Haydn]

Can I ask a very basic question please?

Im new to this forum and this type of collecting.

I have two shell casings with different primers one slotted screw type and the other non screw variety. Both shells are of a similar size why and what are the differences between these two types of primers?

Many thanks
Haydn.

 

[Falcon]

The slotted screw-in primer usually has an intermediate booster charge which is ignited by the percussion cap to set off the main charge. Most artillery calibre rounds use these primers as they also make the case easier to reload. The primer which is pressed into the case is simply a percussion cap with no intermediate charge. Pressed in primers on artillery cases seem to have been mostly used by Germany around the fFirst World War period.

 

[Chris 42 RQ]

Electric Versus Percussion

A very simple explanation is that different countries and manufacturers opt for different types of "Primer" for many reasons.
Tank Ammunition tends to be "Electrically" initiated and Artillery Ammunition tends to be "Percussion".

These are NOT hard and fast rules by any means.

Also percussion Primers vary as your two examples show, one of the reasons to use a screw in "Primer" could well be to facilitate easy reloading of the case once it has been returned for re-filling.
"Press fit" Primers are seen as more difficult to replace for re-filling and tend to be put into "One off" use cases.

The British Navy tend to use "Electric" Primers along with the British Tank Ammunition.

Screw in primers may well not be as "waterproof" as a "Press fit" percussion primer as water can under certain circumstances ingress via the thread and spoil the contents of the case.

Someone here will come up with the definitive reason why both types are used.

 

[vickers]

The left shell is a belgian shell is for the Canon 75 Tir Rapide, wich means quick fire, the maker is FN (Fabrique National) and the primer is made by AFM (atelier de fabrication militaire) witch is an exact copy of the german C/12 (Naval) Primer.

 

[pkm594]

Primers are used by definition in ammunition with cartridge case obturation and ammunition known as Tubes are used for systems where the gun breach provides obturation.
Primers are part of the cartridge case where Tubes are fitted into a recess in the breech.

Tubes used in systems for example in british service, 120mm fitted to challenger/2 and 155 H AS90.

Primers used in systems such as, 30mm Rarden, 105 Light gun, 4.5in naval.

 

[2pounder]

primers type

Will add to Falcons comment that push in caps like rifle primers were ok for early black powder rounds and used by most countries, but when cordite came along a booster was required and this led to screw in primers but a lot of US cases have press in long primers with booster possible because they did not plan to reload them?
2pr

 

[Haydn]

Thank you all very much for all your replies - you certainly know your stuff.
Learning bit by bit......:tinysmile_hmm_t2:

 

[Chris 42 RQ]

Learning curve

Thank you all very much for all your replies - you certainly know your stuff.
Learning bit by bit......:tinysmile_hmm_t2:

That Haydn is what this forum is about, I learn new things everytime I turn the puter on and come on this site !

Really it just proves how thick and ignorant I am when I look at all the information here !

 

[2pounder]

knowledge

Chris I'm sure you aren't really as bad as you suggest. We all have specialist knowledge in the particular fields that we are interested in. What the creators, administers and moderators of this site allow us to do is to tap into world class knowledge where we all can learn and contribute to others knowledge by helping answer their questions. This is starting to sound a bit 'suck butt' but its got to be the best site in the world certainly for ordnance info. and thanks must go to those who started it.
2pr

 

[Chris 42 RQ]

Only the best !

Thanks 2pounder for your nice comments and I whole heartedly agree with the "thanks must go to" bit as this simply is the best site (fact).

I used to think I knew a lot but coming on here has been a real eye opener as it has shown me that I know a lot about a little !:sad:

As you say we are all specialists in our own fields.:tinysmile_fatgrin_t