The UK Government may change its mind and preserve the historic names of two Welsh regiments, say campaigning MPs.
The Fusiliers are to merge with the Royal Regiment of Wales
A cross-party group met Defence Secretary Geoff Hoon on Tuesday morning to discuss its concerns.
The MPs have been asked to draw up a document, explaining why the Royal Welch Fusiliers and Royal Regiment of Wales titles should feature prominently in the merged Royal Welsh Regiment.
MPs said the minister promised that his decision would be looked at again.
Mr Hoon told the group of Welsh MPs that their submission would be passed to the Army Board for consideration.
The controversial merger was announced in December as part of a military review.
MPs are unhappy that the regiments' names will be lost with the arrival of the new title.
The new two-battalion Welsh regiment will have their old names later in the new title.
But this contrasts with new Scottish regiments, which can display their old name first, and the new name second.
Brecon and Radnorshire MP Roger Williams said the campaigners "didn't have a very sympathetic reception."
Another member of the delegation, shadow Welsh Secretary Bill Wiggin, said Mr Hoon's response was negative although there was "a glimmer of hope."
Meirionnydd Nant Conwy MP Elfyn Llwyd said: "The Secretary of State didn't shut the door.
"I believe that if the army board receive the whole story there is a possibility that they will reconsider."
Geoff Hoon has allowed the Black Watch to keep its name prominent
The campaigners also handed a 7,000 name petition to Downing Street on Tuesday morning in protest at the merger.
The cross-party delegation also included Merthyr Tydfil and Rhymney MP Dai Havard, shadow defence minister Bill Wiggin, Montgomeryshire MP Lembit Opik, Wrexham MP Ian Lucas and Vale of Glamorgan MP John Smith.
Mr Williams said before the meeting: "Tradition and 'hiraeth' (longing) play a vital role in promoting loyalty to the Welsh regiments of the British Army.
"But keeping historic names isn't about looking back, it's about ensuring adequate recruitment to keep these battalions up to strength.
"While the Scottish regiments have been allowed to keep their regimental names in a prominent position, this has not been allowed in Wales."