What do you need to change out on a tigger pack, like if you were taking a G3 trigger pack and wanted to convert it for use in a 9mm Mp5?  I know the extractor needs to be changed.  Anything else?  

Some people also change the hammer spring (I do), others don't and report no function issues.

osprey21, anybody, is there a meaningful difference between the hammer spring on a 91 and a 93?

I have a nice tuned (Springfield) JLD PTR91 trigger group, but when I changed the ejector out for my 93 version and stuffed it all into my V93 the 93 immediately began to have FTE problems every few rounds...been trying to decipher what else it could be

Quoted: osprey21, anybody, is there a meaningful difference between the hammer spring on a 91 and a 93?

No.

I have a nice tuned (Springfield) JLD PTR91 trigger group, but when I changed the ejector out for my 93 version and stuffed it all into my V93 the 93 immediately began to have FTE problems every few rounds...been trying to decipher what else it could be

Don't know how many rounds you have thru the V93, but check your extractor spring. You should not be able to move the extractor with your finger, if you can, change the spring. Extractor springs are probably THE most frequent cause of FTE's in HK's.  I replace mine every couple thousand rounds.

thanks, will do

There is nothing wrong with your extractor. New spring was installed at build. When you swapped trigger boxes, your ejector is probably now sitting too low and not tossing the brass out. Turn your gun over so you can look in magwell. Pull back cocking handle (and bolt ) untill ejector is even with bolt face. Push up in ejector, towards bottom of bolt. There should be none to slight movement of ejector. You can order a taller ejector if needed.        

Thanks K9, that appears to be it, the JLD trigger box is apparently slightly different specs?  Whatever, I need to find out where you get a taller 93 ejector to make this box work.  Any source for those?  Is there a special designation for the taller versions?

thanks