A400 Xcel Problem - fails to fire

Bit of an odd one this. Last few weeks, when first taking my A400 out of the slip and trying to fire it for the first time it just clicks when I pull the trigger.  After ejecting the cartridges unshot a couple of times with it doing this it will fire and then won't be a problem for the rest of the round.  Put it in the cabinet for a week and it does it again on the first stand.  Happened 4 outing on the trot now.

Anyone else experienced this and have any idea what's causing it?

Firing pin/bolt problem? Have you dismantled it and given a good clean

Most strange

are you cleaning it properly

When you eject the unfired cartridges  are the primers on the ejected round showing a light strike ? 

Some cartridges (Fiocchi are one of note) have slightly deeper primers. A swap from TT1s to Evos solved the problem on my daughter's Winny.

Martyn is on the money - check to see if the gun is doing its thing and whether the primers are showing a light strike when they don't (and maybe when they do) fire.

It maybe that it takes a couple of shots to ease the pin into full travel.