My GAMO Urban

[avator]

Good Monday Mornin' Y'all.

Been sticking my nose in another Urban thread and it inspired me to get a little up close and personal with mine.
First a little history on how I got the gun and what I did to make it my own....
I bought this gun a few years ago from another member for a couple hundred bucks. At that time it was a killer deal in comparison to what they were selling for new... unless you were able to tap in on a few good deals that were floating around.
Right out of the gate, many considered the Urban a candidate for the FUGLY club mostly because of the "pickle" hanging off the nose of it. I suppose some didn't care for that camel back fixed cheek riser either. I didn't have an issue with either.
The cheek riser felt very comfortable for me and, in my opinion, the "pickle" looked a heck of alot better than the "soup cans" that many others are replacing them with. The ultimate for me would be to do a full shroud with baffles but I don't have the spare funds or means to do that at this point and most likely will not.

[avator]

I happened on a deal for a leaky BSA Buccaneer and I bought it basically for the wood stock. I swapped the stocks and eventually resold the Buc.
One of the popular mods was the trigger. The simple mod was to just use a longer screw for more adjustability. But, for me, the absolute game changer was to install the Charlie da Tuna trigger. Short first stage with a solid stop and light glass breaking snap for the second stage let off. Very smooth and predictable for every shot.
There are also folks 3D printing inserts for the "pickle" and doing a great job of reducing the report. I'm not in the backyard situation so silent shooting is not something I care much about.

[avator]

The other thread I mentioned in the first post here was more geared to getting more power out of the Urban. Big power is never a goal for me. I have guns that were made for more power and if the need arises, I'll simply go in the house and grab one.
I shoot paper and reactive targets mainly so accuracy and shot count are more of my goals. By accuracy I mean, consistent accuracy throughout the shot string at a range within 35 - 40 yards. By shot count I mean more time on the bags and less time on the compressor. For me the key to that is to adjust for a low ES bell curve. And sometimes (with unregulated guns) it even requires lowering the fill pressure. The Urban has a max fill of 3365 but that don't mean I have to fill it to that level.
I have not done any adjustment to this gun since I bought it. The accuracy was very good and I didn't see any reason to do so at the time. But now the "tinker bug" seems to have bitten me. Mostly due to having more time on my hands due to retirement.
I ran a string over the chrono yesterday. With the gun filled to a tad over 3k, between 3100 and 3200, this is what I got with the CPUM 14.3 domed pellets and a cold gun. (note the ambient temp)

[Rat Sniper (AKA: PaulT58)]

That's not even the same animal it started out as...  It dresses up really nice! 

[avator]

Yeah, BTW, I'm glad you popped in on this....
As the original owner of this gun, do you remember having done anything to it as far as upgrades or adjustment?

[Rat Sniper (AKA: PaulT58)]

Yeah, BTW, I'm glad you popped in on this....
As the original owner of this gun, do you remember having done anything to it as far as upgrades or adjustment?

Nothing significant.  I do recall increasing hammer spring tension in search for higher power, but discovered accuracy suffered due to said adjustment, so it was tuned back down to regain the accuracy.  I also remember messing with the pickle to make it more backyard friendly, because, unlike you, I have neighbors close by on both sides!  I did figure a way to insert another LDC into the end of the pickle, but never did get it working well.  This was before the 3D Printers because so prevelent and cost effective.

[avator]

Just for comparison....
Back in the day Mike Mellick bought a pallet of Xisico XS60C C02 guns that were disontinued. He changed out the tubes and converted them to HPA and sold them with no warranty as "The Tinkerer's Dream" for $100 each. They weren't for the "out of the box" backyard shooter. They were more for guys with the knowledge and desire to tinker and modify and tinker and modify is what they did. It was recommended not to fill these guns over 1600 to 1700 psi for safety reasons. The tube threading was not consistent and some fit looser than others making them less safe than others. I checked mine closely and had regular contact with Mike for advise as I went. All said and done, I felt comfortable going to a 2k fill with mine and it has sat with 2k in it for months at a time since then. Others are advised to do it at their own risk.
One of the goals for these guns back then was the 20 for 20 challenge. 20 shot at 20 fpe.
I hit that mark with a 1900 psi fill with nothing more than hammer spring tinkering and the BStaley oring stack.

[avator]

Yeah, BTW, I'm glad you popped in on this....
As the original owner of this gun, do you remember having done anything to it as far as upgrades or adjustment?

Nothing significant.  I do recall increasing hammer spring tension in search for higher power, but discovered accuracy suffered due to said adjustment, so it was tuned back down to regain the accuracy.  I also remember messing with the pickle to make it more backyard friendly, because, unlike you, I have neighbors close by on both sides!  I did figure a way to insert another LDC into the end of the pickle, but never did get it working well.  This was before the 3D Printers because so prevelent and cost effective.

Thanks, I just wanted to be transparent on what changes from out of the box condition might have been done on this gun.

[avator]

OK, I don't know the actual tube volumes on these 2 guns are but I am sure that difference will affect the results. Pretty sure the Urban has significantly less volume. We could probably do some reseach and find the actual numbers. I think I remember the Urban being reported to be 110. That said, even though the pressure is 1k greater in the Urban than the FD-PCP we don't have the volume and shot count will be diminished.
But the Urban is what it is and limits what I have to work with.

[avator]

I am not mechanically inclined or outfitted to manufacture or turn out parts and pieces such as custom transfer ports which I am sure would make things much easier to lower, flatten and extend that shot string while maintaining accuracy. So I get to work with what I have.       Which is hammer spring swaps and adjustment, fill pressures and the possibilities of using the BStaley oring buffer (stack). Again, I've never been inside this gun so I don't even know if I can use the oring buffer. But, we're gonna find out.   

[avator]

Not quite finished with my coffee sipping stage of the morning and I was doing a bit of looking around on the web. I was looking at schematics to get an idea of whether or not the Urban would be BStaley buffer friendly. I ran across and something at the Bagnall and Kirkwood site. The BSA platform of which the Urban is part of, offers 2 different power levels. Apparently, like Canada, the UK has a power limit on guns. With that, there are 2 different poppets available. One for the 12 fpe limitations and one for those of us who are not regulated.
Again, I'm not the airgun guru that many here are so I have to ask questions...
Would that reduced power poppet help me reach my goal of lower power and extended shot string? Would that increase the ES of the bell curve?

https://spares.bagnallandkirkwood.co.uk/product/gamo-knock-off-valve/


I wouldn't have an issue with getting 40ish accurate 12 fpe shots from this gun if possible.

[shaky2]

What is this BStaley oring stack you keep mentioning?

[avator]

You simply stack a series of snug to the ID of the tube fitting orings around the valve stem against the back of the valve to buffer (limit) the strike from the hammer. It controls how far the hammer is able to crack the valve open. Other folks do it with an SSG which requires some machining. I prefer simple reversible mods.

[avator]

Ok, before it's said, I know a regulator would probably help but, first of all, they are pricey and I have budget limits. Secondly, as mentioned, the volume on the Urban is already small and I don't want to reduce it anymore with a regulator.

[3crows]

I have had both of my Urbans apart numerous times. My #1 leaked everywhere new out of the box, valve, fill port and the air tube had grooves inside it. The Gamo lady was finally convinced to send me the parts for the valve and fill port. The grooves were difficult to deal with. I used a 1 inch ball hone to grind them out of the tube. Then polished with Scotchbrite on a mandrel and then used a home made hot blue to restore the finish.

The BStaley mod is not likely applicable to the Urban. The Urban in several areas is a little more advanced shall we say than the Marauder. It has for example an O-ring that seals the transfer port on the poppet stem rather than allowing a calibrated (lol) leak as does the MRod.



Rifle #2 was solid from the box but it was apart for the TP replacement, barrel port reaming and some other things.


The various iterations of the same rifle (as the Urban) have been made by BSA. If you got to Bagnall and Kirkwood you can see that the knock off valve, transfer port and Hammer spring are offered by various part numbers depending upon power level.

https://spares.bagnallandkirkwood.co.uk/wp-content/uploads/2016/04/GAM3-Exploded-Diagram.pdf

When the sun sets bad thing come about:

[avator]

Thanks James..
Just as I expected there would be bumps in the road making what I want to do difficult while keeping it simple.
I appreciate the diagram.

[3crows]

Country Store and Bagnall are the two places (may be the same place?) in England to order parts from. I have ordered via phone with some consternation from the very nice but conflicted Gamo Lady also. Nothing against the two places in England, CC issues plague many businesses, but after placing an order for some this or that part I found that I had bought an expensive turntable and stereo set in Germany also. Darn, it never came. And I have five turntables but not that one. So, just be wise and on the watch buying on line with CCs. Yes, the bank took care of it and I did notify the particular site.

The #2 before I dug into it and changed out the TP, reamed the barrel, removed the pickle and sleeved the barrel. I love the Urban. If it had a side lever and came in a .25 then I think my dreams of an M3 would come to an end and likely I would never had gone down the Marauder hole.



A charging HOSP is not to be taken lightly  . I feel as confident with my Urban in hand facing it down as I would with my .45-70 Marlin SBL facing down it's early ancestor T-Rex. Just put that bullet right behind those scrawny forelimbs and DRT! Works for avian dinosaurs too!

[avator]

Note...
I'll be using the GX CS3 to be filling the gun today. It has an auto shut off and my Yong Heng does not. This will insure that each start fill is the same.

[avator]

James....
I'm not out in the Red Shed yet and don't have the gun apart and in front of me. But I was thinking about what you said about the design of the poppet with the oring would prohibit the use of the BStaley buffer. And again, I'm just picturing in my mind and looking at the diagram. If the hammer spring adjustment is at all effective in changing the power setting, how would the oring buffer not be capable of controlling (limiting) the hammer strike?

[3crows]

James....
I'm not out in the Red Shed yet and don't have the gun apart and in front of me. But I was thinking about what you said about the design of the poppet with the oring would prohibit the use of the BStaley buffer. And again, I'm just picturing in my mind and looking at the diagram. If the hammer spring adjustment is at all effective in changing the power setting, how would the oring buffer not be capable of controlling (limiting) the hammer strike?

On the road still driving. The poppet stem has two ODs, a small one at the TP and a larger one that protrudes through the valve and has an O-ring groove to seal the TP/valve from blow back. The hammer rides in a plastic sleeve and is without an adjustable striker. The striker portion protrudes from the bulk of the hammer. The HS most definitely will vary power and is behind the back cover and easily gotten to. The hammer spring quickly becomes coil bound and the gun will not cock. What is needed is a slightly stronger spring rate so as not to have to coil bind the spring to get power up. As I mentioned earlier, the cocking pin can somehow slip down and I think this happens due to excessive force as the spring binds up when trying to push the power up. Thus my wish for a slightly stiffer spring rate so as not to coil bind the HS.

I do not see how slipping an O-ring into the air tube behind the knock off valve would do anything as it would not impinge upon the hammer at all. You might could slip a very small O-ring over the knock off valve poppet stem and let it float captured on the poppet stem. Really, I am not getting hammer bounce as I do so easily with the MRod. The only time I notice hammer bounce with either Urban is when I shoot them down below about 1500 psi, then the pop becomes a b-l-aaat. Not unlike the MRods b--rrr--rrr--ppp.