Bolt sticking (ULT related)

[Friendly-fire]

Okay, since I got my ULT I have had problems with the bolt occasionally sticking. It fires, and goes back, but it just barely does not set. I have to take off my hopper and push it back. This is not because of pinching a ball, I get the same problem dry firing. The weird thing is the problem becomes worse the more shims I put in my ULT, even though more shims improve how fast I can shoot. I have actually been running 3 shims for a while, which is alright, but it hasn't completely eliminated the issue and I want to rip.

If I oil up a good bit, it does reduce the frequency, but I don't want to pour oil into my gun every time I want to play. I think I may just need to use the longer springs. My gun came with one spring, 4.6cm long installed already. The other two are both 6.1cm long. Sadly I don't have air right now, so I can't throw in a longer spring just yet. My questions.

Does it sound like a spring issue to you? I can't see it being a problem with the lvl10, however I know it is directly related with my ULT.

Would cutting the spring be a good idea? and what is the best way to do that? 1.5cm is a big increase, and it wasn't a constant problem. I figure if a longer spring is the answer, I should trim one of them down (probably the silver, not the red one). Any advice on the length I should go for would be great too.

Thanks for any help, I really did spend a time hunting down help on this forum and another, so I really hope I didn't miss this being answered already.

[michbich]

I don't have knowledge of the ult troubleshoot. So i can't help you in that department.

But concerning the spring, i would try the longer one. Defenatly can't hurt to try. About cutting it, install it first and check how gentle it is, maybe it's just right. I wouldn't cut the spring, it could cause premature wear on the part that rests against the cut end. If you do decide to cut it, make sure you remove all edges.

[secretweaponevan]

Bolt stick is a powertube issue 99% of the time.

Use oil.
Use the largest carrier that doesn't leak, not the smallest that will allow it to fire.
If it is failing to reset after it "LVL 10's", add a shim.

Edit: It could also be that your field strip screw is too tight.

[Friendly-fire]

I actually had leaking problems before, and set it one carrier smaller (I am pretty sure it was one) which is why I hesitated to think it was that.

I know it is not the field strip screw. I just tighten by hand, and don't even tighten it that hard. Once I get air I will take your advice and go up one carrier size, see if that fixes it without causing leaks. If not, then I will go with the spring.

[TwilightG]

The smaller carrier creates more friction making it more prone to sticking.
If the current or larger carrier still leaks, it might be worth getting a new carrier o-ring.

Oil helps to prevent stick due to the lubrication of the o-ring if it's too tight but