GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Masochisti on July 25, 2015, 09:22:55 AM
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Heres UNREGULATED 50 shots from 200bar to 100bar. Used Gamo ProMatch 1g (15,43gr).
I used these because I got them cheaply from the store next to me and plan to use others pellets at that weigh range @ 800-850fps:
(http://i51.photobucket.com/albums/f374/Matti_Salminen/hatsan_at44_pal_zpsnbxrk5rc.jpg)
Now after Huma regulator at 110bar setting:
(http://i51.photobucket.com/albums/f374/Matti_Salminen/hatsan_at44_regged_110bar_zpskhjxxlhg.jpg)
Its definitely flatter now...
Why only 30 shots you ask? That's all I could do before the air cylinder dropped down to regulated 110bars!
So I lost 20 shots to somewhere? Before regulator the gun used roughly 2bars per shot, now its 3bars per shot :o
Pumping the gun from 100bars to 200bars takes almost the same effort as before so its definitely hogging more air.
Any ideas what could cause this? I have not done any other tunes for the gun yet.
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When you fit a regulator you create a lower pressure area in front of the valve, so the valve does not have the same force of pressure to help it close after you have taken a shot and more air can escape before it does close.
The main ways to reduce excessive air consumption include (in order of efficacy) :
Back off the hammer spring preload to the full extent
Fit a heavier gauge valve return spring
Plug the five holes on the outlet side of the valve, the ones that do not match up with the transfer port, with set screws
Fit a lighter gauge hammer spring
Try these in incremental steps and I think that you will notice a clear difference in how much air you use per shot.
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Forgot to mention that fitting a regulator can cause the pressure indicator on the end of the air cylinder to indicate a lower pressure in the cylinder than is actually the case, so trust the pressure gauge on your air source (pump or tank) and not the one on the gun.
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So if I adjusted the regulator for higher pressure -> more force pressure for the valve to close -> less air used -> have to use heavier pellets since the gun shoots at higher pressure?
Pump and gun are both on same level regarding the pressure. 200 bars on the pump > 200 bars on the gun.
Gun was also a lot louder when regulated at 110 bars... non-regulated I noticed it getting louder after 130 bars. Heh... it all makes sense now! :D
Off to buy a long 4mm hex key and some JB... thanks for the great reply!
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So I tried to back off the hammer spring (counter clock wise) and the gun ended up hogging even more air... 20 shots > 100 bars. Tried 2-4 turns CCW. I think the regulator is set too low so the valve is letting too much air, that is the number 1 problem here. I'm going to turn the reg all the way up to 140 bars and then back off the hammer spring to lower the velocities. Also I need to plug 5/6 valve holes and see results after that. Also the trigger guard screw had its threads stripped. Anyone know what size it is? M5 x ?
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Contact bwalton here on the forum.
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So I tried to back off the hammer spring (counter clock wise) and the gun ended up hogging even more air... 20 shots > 100 bars. Tried 2-4 turns CCW. I think the regulator is set too low so the valve is letting too much air. I might turn the reg all the way up to 140 bars and then back off the hammer spring to lower the velocities. Also I need to plug 5/6 valve holes and see results after that.
I'm sure there are a lot more scientific ways but here is how I set my reg. Before I installed my reg I turned the hammer tension all the way to zero-CW and filled the gun to 2000 psi and shot a stream to see the average fps. My stream showed it was still higher than I liked so I next tried 1500 psi. This worked so I set my reg to 110 bar. So my performance is between 200 -110 bar. This kept my velocity to where I liked and showed where the reg would fall off.
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So I tried to back off the hammer spring (counter clock wise) and the gun ended up hogging even more air... 20 shots > 100 bars. Tried 2-4 turns CCW. I think the regulator is set too low so the valve is letting too much air, that is the number 1 problem here. I'm going to turn the reg all the way up to 140 bars and then back off the hammer spring to lower the velocities. Also I need to plug 5/6 valve holes and see results after that. Also the trigger guard screw had its threads stripped. Anyone know what size it is? M5 x ?
AT44 hammer screw goes clockwise to reduce force.. You are turning it wrong way.
don't dick with more than one setting at a time. Leave the reg and tune for velocity and shot count.
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When fitting with a regulator, yes you have to adjust the hammer force also, but what is more key is that you know the gun and how to do it, ccw is increasing the hammer strike which you do not want, and a regulator is made to make shots more constant, those unregulated shot strings most of those shots are not usable.... A regulator will give you a few more shots, but there is no free lunch your shots are going to be base on your air capacity of the air tube. A regulator is to give a gun a great ES that comes into play at long distance shooting, the shorter that you shoot the less the ES is in play. But we all look for the best that a rifle can attain.
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If you know how to read the shot string you will find that in your un regulated string only shots 18-38 are useable thats about 20 shots and if you look at the un regulated string Shots 2-24 are useable which are around the same shot count and a few more 23shots, tuning will yield you even more useable shots...
unregulated string of useable shots
hi- 938fps
lo- 920fps
ES- 18fps
Regulated string of useable shots
hi- 849fps
lo- 840fps
ES- 9fps you might say that you had some 830's in there but I knock those out because you might not know that after each shot you have to give the regulator a few seconds to build back up.
hope this helps.
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I'm sure there are a lot more scientific ways but here is how I set my reg. Before I installed my reg I turned the hammer tension all the way to zero-CW and filled the gun to 2000 psi and shot a stream to see the average fps. My stream showed it was still higher than I liked so I next tried 1500 psi. This worked so I set my reg to 110 bar. So my performance is between 200 -110 bar. This kept my velocity to where I liked and showed where the reg would fall off.
This is how I had the gun right after I installed the reg. Hammer tension was already at zero CW and reg at 110bar but it was hogging lots of air. Now I just need to make it more efficient... 8)
AT44 hammer screw goes clockwise to reduce force.. You are turning it wrong way.
don't dick with more than one setting at a time. Leave the reg and tune for velocity and shot count.
It was the only way to turn it (and only thing I dicked around after installing the reg) and since it was recommended to try I did. And it didn't work for me but now I know it ;)
When fitting with a regulator, yes you have to adjust the hammer force also, but what is more key is that you know the gun and how to do it, ccw is increasing the hammer strike which you do not want, and a regulator is made to make shots more constant, those unregulated shot strings most of those shots are not usable.... A regulator will give you a few more shots, but there is no free lunch your shots are going to be base on your air capacity of the air tube. A regulator is to give a gun a great ES that comes into play at long distance shooting, the shorter that you shoot the less the ES is in play. But we all look for the best that a rifle can attain.
Great ES and some distance (50-75 yards) is the thing I'm really hoping to see here. I just didn't expect the gun to use more air after the regulator was installed. Just needs to be tuned and I'm up for it.
I'm using this thread for myself to log things and thoughts (and conclusions) of the mods I'm going to make for the gun.
Thanks for the great replies!
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I have the 22 long and have had the valve modified. So I'm getting 40 shots at 900 fps with JSB Jumbo 18 gr pellets and 930 fps with AA 16 gr pellets. I'm getting outstanding results at distances over 100 yards.
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When you regulate a PCP, you can expect it to be an air hog unless you back off the hammer strike... The gun was setup to be efficient at 200 bar, and now you are feeding it half that....The result is that the valve is open way too long, and blowing a lot of air out the muzzle after Elvis has left the building.... Leave the regulator pressure as is, and reduce the hammer strike until you see a slight velocity drop.... If you are not happy with the shot count at that point, you can reduce the setpoint and preload further, and get less power but more shots.... If you are happy with the shot count but want more power, you can increase the setpoint and preload, but you will get fewer shots....
Bob
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I have the 22 long and have had the valve modified. So I'm getting 40 shots at 900 fps with JSB Jumbo 18 gr pellets and 930 fps with AA 16 gr pellets. I'm getting outstanding results at distances over 100 yards.
That is amazing! How much did you modify the valve?
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Leave the regulator pressure as is, and reduce the hammer strike until you see a slight velocity drop.... If you are not happy with the shot count at that point, you can reduce the setpoint and preload further, and get less power but more shots.... If you are happy with the shot count but want more power, you can increase the setpoint and preload, but you will get fewer shots....
Bob
Whats the easiest way to back off the hammer strike? I have already set the hammer spring all the way in clockwise and its not enough.
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I have the 22 long and have had the valve modified. So I'm getting 40 shots at 900 fps with JSB Jumbo 18 gr pellets and 930 fps with AA 16 gr pellets. I'm getting outstanding results at distances over 100 yards.
That is amazing! How much did you modify the valve?
Read the thread
http://www.gatewaytoairguns.org/GTA/index.php?topic=33903.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=33903.0)
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If you can't reduce the preload enough, cut a couple of coils off the spring to get more adjustment range....
Bob
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Hey Masochist,
It's Amazing how complicated the BASICS of PCP tuning are, until you have that Ah Ha Moment and you say "Oh my God - Now, I get it!" Then it's all downhill from there ....... except when things get really complicated -> then just PM Bob - aka: the Blue Cookie Man.
My Two Cents ................. Kirk
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If you can't reduce the preload enough, cut a couple of coils off the spring to get more adjustment range....
Bob
Or you could just fit a lighter gauge hammer spring in case you ever want to return the gun to its original configuration.
Point four of my initial reply, I believe.
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I'm trying to get my hands on hammer spring for better adjustment (or change it) but I can't find any good instructions how to disassemble the rifle? I just need to get the hammer spring.
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No vocal instructions but visuals:
https://youtu.be/ylbewlQ8G44?list=PLqZCgrIpqfgovPwlLPRtUgvpictUBwV-T
https://youtu.be/Lei9eJ-zEEs?list=PLqZCgrIpqfgovPwlLPRtUgvpictUBwV-T
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No vocal instructions but visuals:
Thanks! "Hastan at-44" 8)
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Disassembling this gun seems easy for the main parts! Only problem is that I can't get the transfer port out... It simply wont budge! Nothing should be holding it back unless it has welded itself to the valve port... :o
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Use an appropriately sized allen key and lever it out from inside the brass housing that the valve screws into.
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Use an appropriately sized allen key and lever it out from inside the brass housing that the valve screws into.
Already tried that, no help. Going to tap it tomorrow lightly with a small plastic hammer and see if it would give in just a bit and then push it out.
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Mine was farly tight and took a bit of force to get it out the first time, but that sounds ridiculous!
You could try the lever method again using a short screw inside the transfer port with a head size close to the size of the hole in the brass housing to spread the force evenly and thereby get more purchase on it, perhaps?
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Masochist,
Mine wouldn't come out either. I destroyed it getting to come out, like pulling a tooth. Since I have a lathe, just made another. Good Luck ............ that one really got me ticked :P
Most likely loctited in, heat it up using a soldering iron for few minutes, she may just pop out!
Kirk
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Ok no luck. Its tight...
Well I ended up taking the trigger and safety away > that gave me access to the hammer spring 8)
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So I finally got my hands to that "dang" hammer spring... I think I'm heading the right way 8)
(http://i51.photobucket.com/albums/f374/Matti_Salminen/hatsan_at44_regulated_hammerspring_zpsiwhpaq7p.jpg)
Did 55 shots. From 200 bar to 100 bar. Used Crossman Premier Pointed (14.3gr).
I only took out the round end cap at the end of the spring (inside the hammer, approx 3mm thick?). I think it does have some kind of purpose there so I need to replace it with with something else. Also checked how the top valve hole lined up with the transfer port hole... its a bit off sadly. So before I go plugging those bottom holes I need to find a way to line up top hole with tp.
What a great gun to work with.
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Looks much better 8)
What size are your ports: Valve, Transfer & Barrel. They should be between 5/32" and 11/64".
Plug the remaining valve holes except one, use JB Weld. Shim or trim the valve a few thousands and it likely will line up with the TP.
Make sure you're on the Knee of the velocity curve, using the RVA.
Your shot string will extend to 60, 55 strong shots.
Good work ;)
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What size are your ports: Valve, Transfer & Barrel. They should be between 5/32" and 11/64".
Haven't measured them yet. I've misplaced my caliper, gotta lend one from work tomorrow and check them.
Make sure you're on the Knee of the velocity curve, using the RVA.
So I will turn the hammer force down until I get some serious drop in velocity and then tune it up a little to get back > thus meaning I will get better efficiency. (?)
Whats RVA? ::)
Thanks again!
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- Use drill bit ends to estimate port sizes.
- You are right on about the knee - about 20 to 25 fps below top velocity).
- RVA (sorry) - Rear Velocity Adjustment (or hammer pre-load).
Good Luck ................ 8)
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More work on the gun!
Plugged 3 lower holes on the valve with JB. Adjusted the regulator from 110bars to 100bar. Decided to cut the hammer spring 8mm shorter and added the spacer back into hammer (4mm thick). Adjusted hammer spring 2 turns CCW (getting 790-800fps with 14.3gr which is good for me).
Had 0.77g (11.9gr) RWS pellets laying around so decided to do a chrono with them. From 200 bars to ~90 bar.
(http://i51.photobucket.com/albums/f374/Matti_Salminen/hatsan_at44s_100bar_3valve_5mm_2t_zpsj994cbf7.jpg)
Pretty happy with the results 8)
I did some shooting with earlier settings with CP pointed 14.3gr and at 50m I get 1" groups constanly even with some wind. Getting some JSB 16gr soon, I bet they shoot even better...
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Wow, Matti...nice strings.
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Small update. Not too much work on the gun lately (busy busy...)
Right now it is regulated at 145 bars and it shoots JSB 16gr @ 880fps. I can get 30 usable shots from 200 to 140 bar. Did some shooting (was bit windy though... darn) yesterday and I'm quite happy. All shots done at 50meters. JSB 18gr group quite nicely too. For some reason my rifle does not like JSB Monsters at all. It swings those 25 grainers all over the place.
30 shots, 6 x 5 shot groups, 5.50mm, 5.51mm and 5.52mm. Few flyers but I'm to blame not the gun... ;D
(http://i51.photobucket.com/albums/f374/Matti_Salminen/IMG_20150920_112013_zpstjyk0js8.jpg)
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I plugged all of the valve holes and opened one (the one that lines up best with transfer port) to 4.2mm. Im getting 50 solid shots with 15.98gr JSB:s @ 840fps. Regulator set at around 125-130bar. I think that this is pretty good result (180cc) and leave it where it is. I decided to use last of the RWS 12gr pellets in the middle, thus the "bumb" in the string.
(http://i51.photobucket.com/albums/f374/Matti_Salminen/at44_130bar_reg_zpsv44s99jh.jpg)
Also I tested my old camera with a scope mount to record some shots done (2 months ago with old tune settings and cheap chinese 6-24x scope, got new scope coming now). Black background and better light would work better to see the pellets flying but meh... just a test so far.
https://vimeo.com/140342270 (https://vimeo.com/140342270)
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I should have read the whole thread before I posted this link:
http://www.gatewaytoairguns.org/GTA/index.php?topic=74919.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=74919.0)
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I should have read the whole thread before I posted this link:
http://www.gatewaytoairguns.org/GTA/index.php?topic=74919.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=74919.0)
I've been reading rsternes posts and value them highly. Great info and help!