My Urban broke.....

[toddbrat]

Title says it all. I noticed it was getting a bit hard to seat the pellets, which is unusual as I don't have the O-ring on the mag. It did this a couple of times and then was fine, the last time it wouldn't budge after firing. I put a bit more pressure on the bolt handle then the entire bolt group almost slid out. It is dead in the water now with just over 2k psi. I can't cock it, cant return the bolt handle to battery. So the question....

How the heck do you empty the air?! I've dumped the air many times in the past by firing, but that is out of the question. Any other way to degas? My only other thought is cracking the fill port threads to bleed, but I'm really hoping there is a better way. I tried the hand pump and slow release I've used on my Maximus in the past as a long shot and what I thought, different valve design won't allow the backflow.


I

[Rob M]

can you back off the gauge /. that's easy and will leak out slowly

[toddbrat]

Thanks, Rob. I'll give that a shot.

[Rob M]

once u hear it PSHHHHHH let it sit and do the work on its own.. don't keep backing it offf

[dlee]

definitely keep us posted on what happened once you figure it out!

[toddbrat]

Looks like cracking the gauge worked. I loosened it about 3/4 to 1 turn, didn't hear any air coming out, but it was date night with the wife so left it alone. Checked it when we got home and it had leaked down to almost 0. A quick turn of the gauge and one small little puff and it was empty. Time to tear it apart:

The cocking pin bolt snapped. This is a 2.5mm x 15mm screw that sets inside the cocking pin and marries it to the bolt. Going to try to source one locally before ordering, the only place I've found them is John Knibbs in the UK.

[dlee]

Thanks for the update. Your local Home Depot should have M2.5x20 pan heads. At my local store they run $0.58 apiece. Alternatively, mcmaster has the socket caps, which you buy 50 in the pack (for $3 +s/h):
https://www.mcmaster.com/#91292a018/=1e7ldbo

[CraigH]

Glad it is diagnosed.   I do not know the precise head configuration required, appeared to be polished, but here is an amazon listing.

[toddbrat]

Thanks guys. HD here doesn't carry them, we have 1 hobby store that is only open when the owner is in the mood (today isn't one of them). We do have a Fastenal but their closed today. The head is polished and looks like the replacement needs to be as well. I'm going to wait till Monday and if Fastenal doesn't have them will order 1 from Knibbs along with a new transfer port. That's for another project.

[toddbrat]

Was about to hit the order button on airgunspares to order the new bolt and a 20j transfer port when I thought I'd call Gamo and beg/plead with them for the bolt as I've heard they don't sell "parts" directly. I spoke to a lady in customer service that was super friendly, offered to send me the parts diagram to get the part #, told her I had the number so no need. A quick check revealed they have 5 on hand but no price so she'd have to get with their purchasing dept. and call me back. 5 minutes later, she called to tell me it was $1 and with shipping in a padded envelope I'd have it by the end of the week for less than $4 total. Not sure if things have changed with Gamo selling parts directly, but that was as painless as I could ask for. Will hopefully close this out by the end of the week when the new bolt arrives along with what I'm pretty sure happened to cause it to break.

[toddbrat]

...And now it is fixed. Bolt arrived today direct from Gamo.

Pretty sure I was the cause. I shrunk the transfer port a bit to try to get better efficiency as I typically keep the power very low. There is a very small pin that goes directly behind the loading port. I don't think I had it seated fully when I reassembled. That caused enough torque to make it hard to cock and the weakest link was found.

[rkr]

Interesting, old style BSAs used M3 bolt and even those may break after extended use (thousands of shots). Looks like they downgraded a rather vital component in the gun. It's too bad as they could have redesigned the probe for M4 bolt just as well.