Xcortech 3300 arrived today, claims my M4 is 344 without hop and 334 with hop. Unsure whether there is any point messing with the spring.
I have the guarder sp 85,90,100.
All springs will lose a bit over time.....
chrono's will vary a smidge - some more than others - but usually xcortech's are pretty much accurate as possible
Though at TWA it was just on borders of 350 - 352
now it could be starting to break in now - no offense but I probably did more shots in morning than you did all day
Mall is max 340 I think....
what you could do is leave gun precocked
pop rear pin, slide top receiver forward on CM18
you should see the blue cylinder with a hole/port in it - one left/right side
pull trigger and watch for piston going back past the port
leave it in this precocked state overnight
re-test Saturday - bet it would of dropped a bit more
to be absolute honest if somebody's gun was a smidge smidge over on the Mall's chrono
I ain't gonna worry about 5fps
it is people shooting like dicks overkill etc... that pi$$ me off more than 5fps
what is ya mp5 shooting coz that was on borders of the Mall you said
so compare the two guns and see if they are similar
or the chrono you got might be say 5% or so out...
test ya mp5 first and see what ya get before doing owt
if it ain't broke - give it to me I'll f*ck it up for sure