Ics l86a2. Bore up kit

[ThunderCactus]

try cleaning the barrel, but the issue is most likely the way it was re-assembled. I don't think BB bastards have ever caused a problem in any tightbore
Make sure your hopup is set slightly on. If it's off it will cause problems and if it's on too hard it will cause low fps and jamming.
Make sure the back of the hop rubber is seated properly in the hop chamber, very lightly grease the outside of the rubber when sliding it into the hop chamber and twist it in so it doesn't snag anywhere.

[Heavy]

Agreed I only use top quality bb's

My Gundoc saying I need to go to a 6.03 that 6.01 too small.

See I am sure its the hoppup......but I am not good at putting things together that's why I use a gundoc.

[ThunderCactus]

6.01s are great if you wash your BB's, mags and gun regularly and play in an indoor, dust free, hermetically sealed environment.
For every other situation, 6.03 is the tightest bore you should use. With my bolt action rifle, even after 120 rounds I could see the accuracy decline due to barrel fouling.

[Heavy]

Update:3 months and still no gun
left the gun at the gun doc told him to put back the original barrel same problem
so any one know about the l86 hopup
still shooting 250 . on .25 I am sooo frustrated

[ThunderCactus]

Sorry to tell you this, but your gundoc sucks.
There's an air leak and it's almost certainly an alignment problem.
If it shot fine before, then lost fps, then still lost fps with the stock parts, it's a gundoc problem

[Heavy]

thanks sir I hope he see this post!!!