I heard that the Urban shoots the EunJin 28gr pretty darn good, and that is a great hunting pellet,Hard to pass on a Sumatra carbine .22 tho .....just messing with you brother,...but really, I'm serious
Here is what I found by cranking it UP in spring tension.Can get 31foot pounds with the standard valve, but for only 18-19 shot. Lets call it 30.5 footy pounds X 18.5 shots...or about 574 foot pounds per fill inside of 4%. Was cranked up in striker spring tension until it ran well with a 3200psi fill.Can get it to 25 foot pounds for about 25 good 25 shots. Lets call that 635 foot pounds per fill. Was set so that it ran well (within 4%) from a 3050-3100 fill pressure.Can get it to 22.5 foot pounds for about 30 good 4% shots., so lets call that 742 foot pounds per fillCan get it to about 18.2 foot pounds for about 37 good shots. So lets call that 674 foot pounds per fill. This one was set up to start at about 2700-1600 psi. So something good i happening, at least for an un-modded valve, at about 22.5 foot pounds X 30 shots. Could try to refine it in-between 23 and 24 foot pounds,,but the difference would be "nothing".Sooo…...on a "one rifle test-basis" (would I were rich enough to test 54-6 rifles at a time...ALSA..not my lot in life to wind the powerballlottery...which would let me test 5=6 "factory supplied/"identical" rifles at the same time).THIS urban wants to run it's best at about 22-24 foot pounds in it's stock form. Can certainly run faster/more energy, but at a reduction of energy per fill..s.If looking foer the best proportion of energy/air use, look around 22 foot pounds. 2850-2200 psi fill.So basically, if you want mega-power (without any valve/transfer port mods) are looking at 30-32 foot pound
Few years ago I tested a 15" BSA barrel in my BSA BR gun. With 4mm stock barrel port and all maxed out I got .22 JSB Heavies flying at 945 fps at 2700 psi tethered. The gun can be filled to 3300 psi so you should be able tune for a short shot string at 900+ fps with that ammo if you open up the valve system.
You may notice that the Sumatra carbine in .25 and the Urban are at the top of my list...Neither have had power mods or adjustments and both are very satisfying.
On mine, the action - including the area where the hammer slides - was full of heavy, sticky grease. IIRC, removing the grease bumped it up ~30 FPS without making any other changes.Unfortunately, it also developed a bit of hammer bounce without the grease there to dampen it.
Quote from: rkr on February 12, 2019, 01:34:12 AMFew years ago I tested a 15" BSA barrel in my BSA BR gun. With 4mm stock barrel port and all maxed out I got .22 JSB Heavies flying at 945 fps at 2700 psi tethered. The gun can be filled to 3300 psi so you should be able tune for a short shot string at 900+ fps with that ammo if you open up the valve system.Thanks rkr. Heavies at 945? That sounds like one heckuva thumper! Question, though: what are your thoughts on the abovementioned valve work? Is that something that is complicated? Or is it something that is fairly straightforward? I'm not a stranger to tools, but when it comes to precision stuff, I tend to be slow on the uptake.
Quote from: avator on February 12, 2019, 08:33:26 AMYou may notice that the Sumatra carbine in .25 and the Urban are at the top of my list...Neither have had power mods or adjustments and both are very satisfying.If didn't have to worry too much about self-preservation, I think I'd be right there with you, avator. I keep looking at the Sumatra...as well as the Flash series. I almost snatched up a Bullboss when Midway had them on special...but thankfully I didn't. So, in the bedroom I can remain. I strongly feel that the Sumatra will fit just about every need I will have. So much so, that I'm almost hesitant to purchase it early on. Manny just had to post up his new Rex pistol/carbine...now I'm thinking about that too.
Quote from: VaporTrail on February 14, 2019, 01:30:02 AMQuote from: rkr on February 12, 2019, 01:34:12 AMFew years ago I tested a 15" BSA barrel in my BSA BR gun. With 4mm stock barrel port and all maxed out I got .22 JSB Heavies flying at 945 fps at 2700 psi tethered. The gun can be filled to 3300 psi so you should be able tune for a short shot string at 900+ fps with that ammo if you open up the valve system.Thanks rkr. Heavies at 945? That sounds like one heckuva thumper! Question, though: what are your thoughts on the abovementioned valve work? Is that something that is complicated? Or is it something that is fairly straightforward? I'm not a stranger to tools, but when it comes to precision stuff, I tend to be slow on the uptake. The barrel port is 4mm in diameter and I just matched the transfer port and valve tunnel to that size. Now this was a traditional BSA PCP so I don't know the factory sizing for this new "based on gamo trigger" thing so you'll have to check and resize. For valve "tunnel" you could go 10% over that in size (don't forget to substract valve stem area from port area) which may necessitate making a new valve poppet. Also check the valve chamber input for restriction. One more thing is the valve stem, I believe that is used to adjust power levels in the gun so check that it's not restricting the flow.
for porting I think you will need a custom poppet..? and the sucker is/looks... to weak to hit harder with a heavier spring/hammer because it is o-ringed... I think it seals in the valve throat... probably great/best for flow but also harder to un-stick/open I think...http://www.airgunspares.com/store/product/16163/BSA-BSA-Buccaneer-K-Off-Valve-24J-Part-No.-16-9029/well there is maybe another way to get more power... it has a longer barrel (18.5") and 50 ish more cc of pressure tank... should buy about 30-40 fps with the heavy stuff..?https://www.pyramydair.com/product/bsa-buccaneer-se-air-rifle-black?m=3611the Urban with spring cranked will do about 640 fps w/BBT 30g... mine without the spring cranked is ~615 fps...https://www.gatewaytoairguns.org/GTA/index.php?topic=149700.20couple of quick loosely shot groups with some harder cast 4-5% tin (rejects was saving for fire lapping) ~.6" at 40 yards(post #10 in link)https://www.gatewaytoairguns.org/GTA/index.php?topic=151471.0should get better with lube and better cast soft lead rounds and better effort by me...point is even with porting the Urban has a 15" barrel... to make use of that porting it also needs barrel length to take advantage of the porting... Knibbs at one time a couple years ago had Buccaneer barrels in stock... hope they start selling the again...porting and a 18.5" barrel should get to above 700 fps with the 30g... and a 24" barrel should get 30g around 750-800 fps...http://www.airgunspares.com/store/product/16156/BSA-BSA-Buccaneer-.22-Rifle-Barrel-Part-No.-16-9383/Me instead of having the 24" Remmy 514 barrel I have turned for the Urban... lost self control and just ordered a Black Wrap .22 Buc to go with my .177 Buccaneer have wanted it for a while and my son wants part ownership so pitched in $125... Guess I am more afraid they are going to stop making the Buccaneer with the 1/2 unf muzzle threads than I want an Urban with a 23"-24" with a long barrel right now... but maybe sometime this summer the Urban will get a long barrel... You can get a Buccaneer valve housing to port...I think they are the same so if you mess up you just lose $ and still have the stock valve... so the experiment is doable...http://www.airgunspares.com/store/product/16144/BSA-BSA-Buccaneer-Valve-Housing-Part-No.-16-9027/long term among other barrels wonder about a 24" CZ 455 .22 barrel... they are nice ant tight... bout .212 at the muzzle... I think the .22 Buc probably should at least hit fpe=grains (671) with spring cranked will see soon... but 32-33 fpe would be nice... now me in the end will leave the Buc stock but will probably mod the Urban... and I agree with Bill, " I recommend you save up and get the gun you really want. "Me I just can not help myself have the tinker gene I guess...
Quote from: VaporTrail on February 14, 2019, 01:42:59 AMQuote from: avator on February 12, 2019, 08:33:26 AMYou may notice that the Sumatra carbine in .25 and the Urban are at the top of my list...Neither have had power mods or adjustments and both are very satisfying.If didn't have to worry too much about self-preservation, I think I'd be right there with you, avator. I keep looking at the Sumatra...as well as the Flash series. I almost snatched up a Bullboss when Midway had them on special...but thankfully I didn't. So, in the bedroom I can remain. I strongly feel that the Sumatra will fit just about every need I will have. So much so, that I'm almost hesitant to purchase it early on. Manny just had to post up his new Rex pistol/carbine...now I'm thinking about that too. Paul, I recommend you save up and get the gun you really want. If you don't you'll be chasing it for quite some time. I've bought, sold and traded well over 200 guns in the past 5+ years. I have <> 100 at any given time, some of which I haven't shot in months.