I i own a Smith and Wesson sigma SW40VE and have some fail to fire issues. It happened with no matter what ammo i put through the gun but it does not do it all the time. When i eject the unfired round there is a make from the firing pin but the round did no discharge. if i manually feed the round back in and pull the trigger again it will fire. anyone have any ideas on what could be the cause to this problem? the only this that comes to mind for me is the firing pin spring could be worn out and not throwing the pin with enough force every time to ignite the primer. Any help would be appreciated and i do not just want to get rid of the gun it is mostly a camp and play gun not used for defense or carry ( mostly due to this issue).

Check that the firing pin hole is clean. I have seen bits of brass get stuck there. The firing pin should be free from oil etc.

wayneshq has given you good advice!  

I, too, would recommend that you breakdown your slide and thoroughly clean out the firing pin channel, striker, and spring.  Look at your owner's manual.  It should tell you how to test the striker for proper functioning.  If it were my Sigma I'd, also, install a new striker spring.  Wolff Gunsprings should be able to help you out.  I use the heavier 6 lbs. striker springs in my Glocks.  If you have a problem finding the right spring then, caliber for caliber, a Glock striker spring should be completely interchangeable with its Sigma counterpart.  

http://www.gunsprings.com/Semi-Auto%20Pistols/SMITH%20%26%20WESSON/NUMBERED%20SERIES/cID1/mID58/dID261  

If you're interested, give Wolff Gunsprings a phone call.  Their tech support department (probably, Dave Koebensky) will - I am sure - be glad to help you out.