Please to help. What is "obturating primer"? Pictured is an 8" x 10" arsenal/manufacturer assembled board showing cutaways of a Frankfort Arsenal model 1900 C base fuze, a 16 second combustion fuze, an obturating friction primer and an obturating electric primer. These primers.... I have not seen befor. They are approximatly 2 1/4" long (the brass body) and about 5/8" at the widest point. Im familiar with obturation and breech closing/sealing systems but where do these go, how do they work? Are they for bagged charge guns? Do the primers screw into the base of the case or the breech of the gun? Are they for large guns? Thanks for your help and patience.
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? Obturating Primers ?
- Thread starter FNG61
- Start date
An obturating primer screws into the gun ,previously they just pushed in,
theres a nice explanation here
http://www.thepirateking.com/historical/cannon_primers.htm
theres a nice explanation here
http://www.thepirateking.com/historical/cannon_primers.htm
Thanks Spotter. That site does give a proper synopsis. I wouldnt have asked except Ive been laboring under the assumption that all the items on the display board are contemporary with the dated item; i.e.; circa 1900. It is confusing to me that there would be primers for muzzle loaders shown with fuzes from the fixed ammuntion, breech loading, quick firing gun era. I'll have to re-think the provenance of the display board. Unless muzzle loaders were still being used in 1900? FNG
i wouldnt be too worried about the provenance as in ww1 they still used friction igniters on some of the british guns ,i recall seeing somewhere recently that a lot of the fuzes that are sold with WW1 german kugel and egg grenades are actually friction igniters from guns and these too are threaded
Hello Spotter. This is the issue that has me stumped. What are these British guns in WW1 that used friction igniters? You arent talking muzzle loaders Im assuming. So the friction primer is screwed into the barrel or the breech block of the gun? There is only about 5/8" of threads to one of these and it would seem that even with a small calibre gun, with the high pressure generated by cordite/nitro cellulose propellant, that the primer would strip out and become a projectile it's own right. So wouldnt it have to be screwed into the base of the shell casing or part of the breech closing mechanism and then have the breech block closed on top of it to ensure a lasting fit? If so then how does the primer activation take place closed away inside the gun? Dont mean to be a pest about this detail but it isnt in any of the (admittedly limited) books, etc, I have access to.
Pictured is one of those German friction igniters (next to an egg grenade and the usual friction fuze) you mention and a picture of the same primer in a German ordnance manual (circa 1900?) listed as a cannon primer (according to one translator). I heard through the gernade collector grapevine that the brass friction primers were used on the kugel and egg grenades to make them into booby traps (beastly!).
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The British called these tubes "Vent-sealing tubes". I think obturating primer is the American equivalent. The tube was self-sealing, and hence allowed obturation i.e. sealing the chamber.
In WWI the BL 12 pounder 6 cwt, BL 15 pounder, BL 10 pounder mountain gun, BL 2.75 inch mountain gun, BL 5 inch howitzer, BL 6 inch 30 cwt howitzer all used T friction tubes.
With the exception of the BL 2.75 inch mountain gun, they were all totally obsolete and only relatively minor participants in WWI. The T tube was inserted in a radial vent i.e. on top of the breech : the radial vent ran through the top of the barrel into the chamber. A lanyard a couple of feet long was connected to the tube, the gunner stood aside and yanked the lanyard. The pin was pulled out of the tube's T piece, generating friction which fired the ignition compund in the tube stem, much like striking a match. The gunpowder in the tube vertical stem ignited, and in turn igniting the charge in the chamber.
The tube had a copper ball which gas pressure forced up and sealed the tube from the inside on firing, and the tube's own expansion sealed the vent outside the tube. None of these were high-velocity guns, so it worked pretty well.
The bigger BL (i.e. bagged charge) guns (of which there was only the 60-pounder when the war began), and all the new stuff, used percussion tubes inserted into axial vents (i.e. running through the breech block and the mushroom) as part of the breech lock mechanism.
Rod
In WWI the BL 12 pounder 6 cwt, BL 15 pounder, BL 10 pounder mountain gun, BL 2.75 inch mountain gun, BL 5 inch howitzer, BL 6 inch 30 cwt howitzer all used T friction tubes.
With the exception of the BL 2.75 inch mountain gun, they were all totally obsolete and only relatively minor participants in WWI. The T tube was inserted in a radial vent i.e. on top of the breech : the radial vent ran through the top of the barrel into the chamber. A lanyard a couple of feet long was connected to the tube, the gunner stood aside and yanked the lanyard. The pin was pulled out of the tube's T piece, generating friction which fired the ignition compund in the tube stem, much like striking a match. The gunpowder in the tube vertical stem ignited, and in turn igniting the charge in the chamber.
The tube had a copper ball which gas pressure forced up and sealed the tube from the inside on firing, and the tube's own expansion sealed the vent outside the tube. None of these were high-velocity guns, so it worked pretty well.
The bigger BL (i.e. bagged charge) guns (of which there was only the 60-pounder when the war began), and all the new stuff, used percussion tubes inserted into axial vents (i.e. running through the breech block and the mushroom) as part of the breech lock mechanism.
Rod
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Thanks for the information Rod. Primers/ignition on the late 1800s guns(non-fixed ammunition) seems to be a topic that has been ignored. Breech closing systems, ammuniton, recoil control methods are all covered to some degree but this one aspect doesnt appear to have been considered by the run of authors or they take for granted that it is common knowledge. Guess Ive been spoiled by alot of the other works that deal comprehensively with their subjects. It does leave the challenge to do more digging to find answers. This site is a great resource. ATB Rob
Thanks for the information Rod. Primers/ignition on the late 1800s guns(non-fixed ammunition) seems to be a topic that has been ignored. Breech closing systems, ammuniton, recoil control methods are all covered to some degree but this one aspect doesnt appear to have been considered by the run of authors or they take for granted that it is common knowledge. Guess Ive been spoiled by alot of the other works that deal comprehensively with their subjects. It does leave the challenge to do more digging to find answers. This site is a great resource. ATB Rob
See here a intresting artical about tubes.
http://riv.co.nz/rnza/hist/gun/firing.htm
Even today modern artilery use percusion tubes to fire the gun, these are put in the breech.
http://riv.co.nz/rnza/hist/gun/firing.htm
Even today modern artilery use percusion tubes to fire the gun, these are put in the breech.
That's a nice article too. Here's a bit from 'Artillery and Ammunition of the Civil War' by Warren Ripley; on spiking guns. "... a jagged, hardened steel spike.... was driven into the vent, flush with the tube... Spiked vents could be cleared... a one third charge packed with junk wads could be set off.... This generally blew the spike out." This is with black powder, to drive out an item that was meant to disable the gun. Which is why Im hung up on how hard it must have been to keep even screw-in obturating primers in the gun in the smokeless powder era.