2 577-450 MH questions

#1

if someone could help with the following 577-450 questions

  1. I have one round with headstamp, KYNOCH 577/450, with a copper jacket soft nose bullet held in case by a neck cannelure ,is this a genuine round ?, did Kynoch make them ?or do I have someones wildcat
  2. this round has headstamp G. K. B ,a common headstamp but it has a VERY long taper ,semi pointed lead bullet ,it could be a proof round ,length of bullet out of case is 1.69 in. and OL of 3.97 in. full ring cannelure ,looks factory but is it ? thanks Randy
#2

Answer for #1?= Not seen a GM jacketed bullet in a factory Kynoch. The French (S.F.M case) did load a GM jacketed soft nose bullet as factory.

Answer for #2 ? = This bullet / OA legnth seems too long for any I’ve seen with that HS. I think British HPT or Proof rounds were loaded with a standard bullet (in most cases) but with or too a higher pressure. The MH case has a cardboard liner which could be removed to pack more powder into the case as proof. Now I may very well be totally wrong on this, & a heaver bullet was used. However a problem may be encoundered with seating an overly long bullet into the rifle grooves. All this is just guessing as I’ve not seen a “proof house” GK B headstamped proof.
hope this is of use & help.

#3

thanks Pete for your imput into no 2 problem, the bullet in this round dose taper off a fair bit after the length of a normal 577-450 bullet to .263 before it rounds to its nose , I will try and organise a picture randy

#4

Randy, another thought, some British proof loads were generated with an over-weight bullet. Most of those I’ve seen were with a cylinderical, absolutely flat nosed, lead bullet with a paper patch almost to the bullet tip. I think these were very early, & prbably used by both houses. But not seen, by me, in MH.