TM MP5 hop issue?

[ben33]

Hello all,

I have had my Tm mp5 for a few months. I bought it used with a cracked gearbox (cheap).

I have since rebuilt this into a new case with uprated piston,bearings M100 spring, correct ported cylinder etc etc.

It now fires at a nice consistent 340 fps.

It's never seemed to fire in a very consistent or straight line and the range is very poor.

I have now replaced the hop chamber wit a new tm one, also a new firefly rubber and zci tightbore.

Still has the same issue though which is confusing as pretty much everything's been changed....

Also tried with various brand .2 bb's

Any advice would ne welcome as I am most confusalled.

[RR01]

Try 0.25 BBs for a start. What range are you getting, as about 40 yards would be good for something with a short barrel length.

[Russe11]

Try 0.25 BBs for a start. What range are you getting, as about 40 yards would be good for something with a short barrel length.

Barrel length does not affect range. Once a BB has travelled down the barrel far enough to reach it's maximum velocity and to stabilise, any extra barrel length makes no difference. In a real gun this length is quite long due to the explosive gasses, in an airsoft gun you only need a surprisingly short barrel. The barrels on my Sten and Owen guns are shorter than on an MP5 and they are both capable of very good range and accuracy.

 

If you have changed the hop and the problem persists, check the barrel. If it had a cracked gearbox, there has obviously been some sort of stress on the gears. If this was caused by a blockage in the barrel it may have resulted in some damage. If the barrel is not straight of has been scratched by an unjamming rod, this may result in bad accuracy and range.

 

And yes, you should ideally use 0.25's

[ben33]

Cheers guys,

I have tried three different barrels, the original, a spare from a friend and also the tightbore I have fitted, all 229mm long.

Will see if 0.25's make a difference though.