doublegunshop.com - home
Posted By: Carl Baird Obturator Disc on Darne - 04/27/20 09:56 PM
Carl here, another question about Darne's. Someone awhile back told me that the disc's on the sliding breach of a high end Darne are called Obturator Disc's and are designed to seal the shell in the chamber when the breach is closed, thus insuring......what? Some people have said it is a safety thing, or it reduces the recoil or...?
I've never had a problem with any of my Darne's, with or without the discs. The only difference in recoil appears to me the direct result of the butt plate or pad you use. Can someone educate me?
Posted By: 2-piper Re: Obturator Disc on Darne - 04/27/20 10:45 PM
One bit of education, the Vast Majority of things which are advertised to reduce Recoil, DON'T, they are purey advertisements. Triple so IF they are advertised to reduce recoil while simultaneously increasing the velocity of the load.
Posted By: Carl Baird Re: Obturator Disc on Darne - 04/27/20 11:46 PM
Thank you, I agree. But what about the obturator discs? They are touted as part of the higher end guns, they obviously require additional machining, and it has to be precise. What is their function?
Posted By: Stanton Hillis Re: Obturator Disc on Darne - 04/27/20 11:53 PM
Here is what Hallowell's Firearms Dictionary says about it:

Obturating Breech - A design of breechloading action whereby the breech slides forward to the barrels (or vice versa) and the one overlaps the other to form a better seal. Ordinarily, modern firearms do not require special obturating breeches because ductile brass cartridges swell slightly when fired, effectively sealing the rapidly expanding gas within the breech.

Personally, I dunno.

SRH
Posted By: Carl Baird Re: Obturator Disc on Darne - 04/28/20 12:09 AM
Thanks, that makes sense.
So to me, it is not an effective selling point if you are in the market for a high end Darne.
Posted By: LeFusil Re: Obturator Disc on Darne - 04/28/20 12:21 AM
Cartridge alignment. Gas sealing. Recoil reducing. Safety (an extra layer of steel surrounding the rim of the cartridge). The easy answer.......gimmick.
Do the disk do all of these things? Probably not. Back in the day it was a selling point and my best guess is....they made them like that, so let’s continue to make them like that. Lots of gunmakers we’re guilty of other gimmicky things too. Darne was no different.
Posted By: Mark II Re: Obturator Disc on Darne - 04/28/20 12:22 AM
If you were in French Indochina with a bunch of wet paper hulls it would push them in the chamber and seal it in the event of failure. The design predates our current ammunition trends.
Posted By: Carl Baird Re: Obturator Disc on Darne - 04/28/20 12:33 AM
All good points and probably appropriate in some cases, but maybe not so much anymore. Thank you.
Posted By: Ted Schefelbein Re: Obturator Disc on Darne - 04/28/20 03:08 AM
I’ve owned guns with them and without them. I’ve always figured I had more control over recoil, or, lack there of, by proper selection of load to gun, and what use it will see that day.
The older style Darne guns that are without obturator discs have the faceplate of the breech dovetailed into the sliding breech, and are superior to the later version, that is held in place with two screws from the bottom. V grade guns, all obturator disc guns after about 1908, have two pins which toss the empties off to either side, something I am also not crazy about. A non obturator disc Darne R model just pulls the empties out of the barrel, and they stay politely there, until you grab them, or, tip the gun.
I think it is so much hype, but, will say it is a nice little piece of machine work, and have never seen one that was poorly fitted. I wouldn’t let the lack of them be the deciding factor on a gun I was considering, assuming everything else was good.

Best,
Ted
© The DoubleGun BBS @ doublegunshop.com