On 02/08/2016 11:14 AM, Gene Heskett wrote: > On Monday 08 February 2016 11:23:58 andy pugh wrote: > >> On 8 February 2016 at 16:12, Gene Heskett <ghesk...@wdtv.com> wrote: >>> One question remains: Does the thread even have to have a spiral >>> component, eg does it need to actually advance into the hole as it >>> turns? Common sense says it should, in order to achieve a gas tight >>> seal against a shoulder at the bottom of the bore. OTOH, with a >>> shell casing supplying the breach seal as modern bolt rifles do, if >>> the headspace when closed is tight enough to prevent a casing head >>> separation, the need for the spiraling thread is removed.
The Krupp I restored has no lead to the "thread" of the breech block, it is a cartridge gun so we had to maintain headspace when refurbishing it. >> Screwed breeches of the Welin or de Bange type are only used with >> bagged charge guns. They both use a de Bange obturator for sealing >> whereas a brass-case gun used the case for obturation. >> This might mean they need no lead, but the pictures seem to indicate >> one. Krupp sometimes used the Welin style interrupted thread with the Elswick cone for a quicker action. It is easy to fire 15 rounds per minute. > That was the impression I came away with. But explain the De Bange or > Welin seal please. > Search on Wikipedia for "Rifled Breech Loader" for a look at early breech loader history and types. Ed. ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
