GTA
Airguns by Make and Model => Umarex Airguns => Topic started by: brapshwing on March 02, 2015, 09:25:41 AM
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So I was shooting my Umarex Surge recently. It was a refurbished model from AGD. My duck hunting buddy had just bought a Umarex and he liked it so I thought I would pick one up. As I was shooting it I noticed that the first stage was a little harder to pull than I wanted. I also noticed that the second stage was too long for my taste. So I took the gun apart to inspect the operation of the trigger and to see if I could come up with an acceptable Mod. Seems like a good idea right!?! This is what I came up with. (The comments below assume that you know how to remove the action and barrel assembly from the stock. If you don't know how to do this then by all means take your gun apart and get started down this rabbit hole called mods)!!
My premise for working on the trigger:
1. The first stage was way too hard to pull
2. The second stage of the trigger pull was too long
Regarding problem #1. We need a lighter spring for the first stage. This problem can be solved by finding a lighter gauge spring for the first stage. This can be achieved easily by sourcing a lighter spring. The factory trigger is 5/8"x1/4"x .025(approximate gauge- I looked on the schematics page of GTA for specs with no luck so this is my best guess on the gauge .020-.025" - I don't have a micrometer to check it). So I went to the local Ace Hardware in search of a lighter gauge spring (bring the factory one with you so you have a reference). I was able to find what Ace Hardware called a #9 which is a 1 5/8"x7/32x.015" spring. I used a pair of dykes to cut the spring down to 5/8" from 1 5/8". The new replacement spring is 1/32" smaller in diameter but it fits into the spring location on the trigger just fine. Of course if you can source a 1/4" diameter version let me know where you found it and I'll swap mine out. If you look at the picture of the springs (pic has the dykes in it) you might be able to notice that I actually cut my spring to about 1/2" and "pulled" on the spring to stretch it out to actually about 11/16". The reason I did this was that I was worried that the spring would still be too strong for my taste. And with the #9 Ace Hardware spring, it's long enough so you get two chances to perfect your spring. Mine worked fine on the first go.
Regarding problem #2. The second stage is too long. A longer trigger adjustment screw can go a long way to shortening the second stage of many triggers on the market today. So I sourced a longer second stage trigger adjustment screw (when you look at your gun, this is the screw that you can see which is in front of the trigger itself when the gun is fully assembled). The factory issued trigger adjustment screw is a #4x1/2" black panhead screw. And it very well may be long enough that you can just tighten it close to all the way in to achieve a shorter second stage. But because I wanted to shorten the second stage as much as possible I sourced a #4x3/4" panhead screw (I wanted to shorten the second stage to the maximum extent possible). 3/4" is too long. So again I used the dykes and cut this time the screw, down to about 5/8". Once you cut the screw down I recommend using some sand paper (I used 320) and smoothing the tip of the screw flat. Surprisingly the factory screw is very sharp and I did not like the sharp screw engaging the trigger mechanism. But that's the expedience of the factory issued set-up.
Once you have these two replacement parts in hand you are ready to reassemble the gun. Replace the factory spring with the newer, lighter spring and replace the trigger adjustment screw with the new one you just dialed in.
The only adjustment you will need to make once the gun is assembled is how much the trigger adjustment screw is engaged to the trigger operation. Adjust to your own liking. For me I wanted the absolute shortest second stage possible. But in shortening the second stage to my ideal liking, I discovered immediately that the automatic safety was not engaging once the gun was cocked.
This process is a matter of trial and error. Be sure to do the following things in pursuit of this mod:
1. Once you are reassembled and ready to go take the gun to a safe area ie outdoor range or other open area
2. Start with the trigger screw in the backed out all the way.
3. Cock and LOAD the gun (keep it pointed in a safe direction)
4. Test shoot the gun to make sure you got it back together and it's operational
5. Gradually engage the trigger adjustment screw to the point where you are happy
6. When the gun is loaded and ready to shoot, keep your finger off the trigger and check to see that the safety is engaged just as it always should be with any Umarex or Ruger
7. If you get it to a setting that suits your shooting happiness then you are done.
8. If you get to the happy setting and the trigger safety does not engage, then you need to back the trigger adjustment screw to the point where the safety engages once you cock and close the breach.
9. Keep in mind that you can "de-cock" a Umarex gun by 1. breaking the barrel open and holding in the "totally" cocked position then, 2. pushing in the thumb safety (it's probably not engaged if you screwed the adjustment screw too deep) and 3. keeping the barrel in the totally cocked 4. pull the trigger and slowly let the barrel down to close the breach.
Once you go through this process and are happy with your settings you probably want to use some lock tite to keep the stock screws from coming lose.
You're Done! And hopefully you will end up with some tighter groups.
I'm happy with the groups I can produce with the Umarex at 20 yards. It's pretty accurate and I took a HOSP with it at 32 yards. I think they call it OSOK. Made my day.
This gun was shipped with a .22 barrel which is bizarre because Umarex does not make this gun in .22, it only comes in .177. For $69 bucks it works great!
One last thought, I didn't tear into the trigger rest of the trigger assembly. I didn't have the time to get into it and haven't gone that deep yet so I'll save it for another day or search the forum for someone else who has done it. It's never going to be an RWS T05 but it can be better than the factory. Let me know if you try it or if you have done this already...
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Brapshwing,
Nice write up on the trigger mod project. Pictures too. Well done. Thanks.
I've also swapped out the spring to lighten the pull weight and replaced the factory sheetmetal screw. One other mod you want to try is the "second screw mod" http://www.network54.com/Forum/184474/thread/1389405103/last-1389438443/How+do+you+do+a+2+screw+modification+T05- (http://www.network54.com/Forum/184474/thread/1389405103/last-1389438443/How+do+you+do+a+2+screw+modification+T05-) lots of folks really like the extra adjustment the second screw provides.
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You are correct in that the umarex trigger is the same as the ruger. I didn't have a weaker spring to swap out, but did replace the stock second stage screw with one a little longer. Made a big difference. I also installed a very thin brass washer on the trigger pivot pin to take out a little of the side to side movement. Very happy with it now. Didn't have a problem with the first stage being to hard so I doubt I'll get a different spring. Thanks
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One other mod you want to try is the "second screw mod"
I will check this out. Sounds interesting as i'm getting more ambitious. John BTW great avatar!
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You are correct in that the umarex trigger is the same as the ruger. I didn't have a weaker spring to swap out, but did replace the stock second stage screw with one a little longer. Made a big difference. I also installed a very thin brass washer on the trigger pivot pin to take out a little of the side to side movement. Very happy with it now. Didn't have a problem with the first stage being to hard so I doubt I'll get a different spring. Thanks
Been a long time, but I'm going to do this mod.
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If the safety isn't engaging, it's because that tab at the back of the trigger is stopping it.
You can file it down a little, so the safety can pass over it.
Just do it a little bit at a time so as not to totally bypass the safety.
If you go too far, give Mike Mellick a call, get another trigger and start over.
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I believe the Umarex Surge is the same as the Ruger Blackhawk Elite. If so, it has a Chinese copy of the TO5 trigger. I have a Ruger Blackhawk Elite and also 3 Ruger Airhawks - same trigger. I've done the 2nd screw mod on all three Airhawks. My Ruger Blackhawk Elite has a pretty good trigger, as is, so I didn't do the mod on it. I did replace the original adjustment screw on it though. I didn't like the pointed screw either. With the 2nd screw mod you can adjust it pretty much where you want. Don't have a problem with the safety on any of them.
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Here's directions from Mike Melik @ FDAR that I used.
"frst remove the cross pin in the trigger blade, now replace it with a 1/16 inch rod or drill bit, using a small pin punch at 90 degrees from the flat inside the blade, tap a mark to guide the drill bit. Now drill through the blade at 90 degrees from the flat using the correct size bit for the size screw you will be using ( I use a 4-40 by 3/4 inch) tap hole from the top and run the new screw with a lock nut in from the bottom until the end is just at the top of the two holes left by removing the cross pin. Polishing the tip of the screw is needed. To adjust the release weight turn front screw in 1/8 to 1/4 turn at a time and adjust rear screw for length of travel in first stage. Adjusting the rear screw may require you readjust the front one. DO NOT GO EXTREMELY LIGHT ON RELEASE WEIGHT. There will be wear over time and the rifle may fail to latch properly if release is to light resulting in reverse droop for break barrels....I have done hundreds of these mods and with correct adjustment it will improve the feel...just don't go for a target weight trigger"
"To Adjust:
1. Run new screw to the same height as the cross bar was then back off 2 turns
2. Back factory screw until tip is flush with trigger body.
3. Cock and load, does it fire?
if so back off until it won't then run rear screw in until it does.
Basic adjustment now done.
If you have too long a pull with rear all the way in run front in 1/8 turn at a time (will also lighten release) the new front screw sets the release point engagement go to far in and no two stage and a creepy trigger if that happens just back it out.."
A couple of photos I found to show before and after Mod.