some weeks ago AlanD send my a pm about my mannlicher :" I have read your post of 15 April 2010 regarding the above rifle. I dont know if you have noticed but the rifle has a British militry proof mark of crossed pennents on the top of the magazine well.
I have seen two other sporting rifles in 6.5mm with this mark."

no, I dont had notice this before, its here side by side with the romanian eagle.

iirc Steyr sold 5000 rifles M 1892 to Romania in 1892 for trials but they made much more barreled actions than this 5000. in the end the M 1892 was developt into the M 1893 for the romanian army and Steyr sold the barreled actions to various gunmakers in britain. all of this actions have the eagle mark and here my rifle become uncommon.

again AlanD:
"Yours is the third sporting rifle I have seen with this British
military ordnance proof mark of crossed pennants. I enclose pictures
of a Jeffrey rifle and scope, in 6.5mm MS calibre. The other rifle
was a Mannlicher retailed by Frazer, also in 6.5MS but without a scope.

These rifles are not recorder in any British references at the
National archives in London. Exactly what purpose they were put to
is unknown, but possibly it may have been for sniping in WW1, before
the issue of officially converted Lee Enfield rifles, however this
is only conjecture. I am trying to do some research on these rifles,
the first step being to find out who the rifle was sold to, by the
gun maker, when it was first made. It may have been purchased second
hand by the War Office or Ministry of Munitions, in which case it
will be virtually impossible to find a record of this . The rifles
would not have been issued to ordinary troops who were short of Lee
Enfield's as supply of ammunition would have been too great a
problem, they would
have been purchased for some specific purpose."

and now:

"Hello

I have heard back from Richard Milner regarding your rifle. Here is what he says the Wilkinson records say.

"Wilkinson number 1458 is recorded as a .375 Sporting Mannlicher Rifle it came from Charles Osborne & Co, price was Ł8-13-0 and was sold to a F C Carter, date is 17 May 1905, not sure if this is the purchase date or the sales date to Carter.
Richard"

So it looks as if your rifle was shipped the UK as a .375 calibre rifle. How it ended up with a military proof remains a mystery. If it did see military service it must have been purchased second hand at some point.

Regards
Alan"