Possible problem with Walter Terrus design - warning to owners

[jbutzi]

I don't intend to be dramatic but I do want to share my experience with the Terrus and what I have learned to help owners avoid a problem that could damage their rifle. I believe this is common to all Terrus rifles but I could be wrong.

I have had three Terrus rifles. After shooting them for a few to many months they developed a problem with accuracy - specifically shooting erratically low. When the first two rifles developed the problem I got a return authorization and replacements. With the third rifle I encountered another problem. Over time the rifle would not cock when I tightened the front trigger screw. I loosened the screws and it cocked but was not accurate. I took apart the trigger on the third rifle and discovered both problems are related to the length of the trigger/stock screws. They are ok when you first use the rifle but with tightening the screws you compress the stock and the screws need to be tightened again. (There is very little bearing surface at the screws.) With successive tightening the screws impinge on parts in the trigger case. The front screw hits the bottom of the sear attached to the front pivot pin and keeps it from cocking*. The rear screw hits a metal stop that gets deformed and forces the trigger case to split open at the lower rear. I experienced this problem on both wood and synthetic stock versions.

My solution is to install shorter screws in both locations or shorten the stock screws. They should be at least 1/8" shorter. Perhaps another solution for the wood stock is to put a large washer between the trigger guard and the wood stock to shim it out and get more bearing area for less compression. There may be other better solutions. I am not expert and this is just my warning to look into it to avoid a these problems.

*diagrams of the Terrus trigger internals on line are slightly different from my rifle's trigger.

The left screw is to the rear and impinges on the metal below the nut deforming it and splitting the case.

The right screw (has been shortened) impinges on the sear below (in picture) and prevents cocking.

 

[Lloyd]

Yeah, I had troubles with mine, could not make it work right, no matter what, didn’t want another, so just threw the SOB in the trash, I got enough problems without having a troublesome gun, Was the most pain in the A.. gun I ever had.

 

[NMshooter]

Sounds like a simple fix. You may have to use a washer if you can't find the right length screw. You might want to check several hardware stores; I have been more successful looking at Ace hardware than at Home Depot espcially if it is a metric screw. Unfortunately, we are seeing this more and more in all areas especially if it is made in China. On several items that I bought recently, I ended up going out and purchase all new screws.

 

[jbutzi]

Tru Value in my town has all sorts of metric screws with hex caps.

Sorry for your trouble Lloyd. I'm surprised they have not corrected this already. Seems like a very obvious problem that should have been sorted out early. or just avoidable altogether by experienced gunsmiths!

 

[broachoski]

Great diagnosis and description of this problem jbutzi.

 

[jbutzi]

Thanks, ski!

 

[MBG]

Thanks I have 2000 plus pellets through mine with no issue but added an extra washer in case, perhaps Lloyd got a lemon, I pulled mine apart tuned replaced trigger spring with lighter spring, added TBT Tophat, 1/2 inch groups at 40 yards pretty consistent and more accurate than guns 2-3 times the price...

 

[RogerV53]

Thank you very much for this post, I don't own a terrus but this is the kind of stuff I and many others come here for.

 

[jbutzi]

It is disappointing to find this obvious problem has not been addresses by a large quality company like Walther. I have my rifle back together with the shorter screws and large washers under the trigger guard for extra bearing. I tried to flatten the deformed metal in the trigger case but I still have a very slight split between them. Unfortunately, the accuracy is still way off. ? While it was working it was great. Not sure what to do next....

Mikebeggs - I hope your rifle holds up. Sounds like you got a nice one. With the lighter spring and polished and lubed internals the trigger is very nice!

Thanks, Roger. I have gotten much help from this forum and only want to add where possible. I am a rookie compared to many others here. ?

 

[Lloyd]

Parrus got same trigger, problem is you try to fix it yourself, , , warranty is no longer good, called the repair facility,talked to gunsmiths, about trigger problem, they offered no solution. So there ya go, I got, Gamos, RWS, Crosmans, Rugers, other stuff, quite happy with what I have, no Walther tho.?

 

[jbutzi]

Yes, I am running into that problem now. I want them to take the rifle back for obvious problem but am getting major push back! ?

 

[boggweasel]

I've found this post 3 years too late. I purchased one with a wood stock and fealy enjoyed shooting it, light, accurate and powerful enough to warrant putting a scope on it. I took it out of the stock for a bit of maintenance work, oiling spring etc upon reassembly, the bolt in front of the trigger guard "popped" and started spinning, acting like a stripped thread, When I tried to remove the stock, it wouldn't come away, the bolt ,although not engaging, was firmly stuck in place holding the works to the stock. I couldn't return it to UMEREX as they only want the action,not the stock and it was well past the warranty. Last week I took it to a friend of mine who has a mech shop, we cut the bolt head away (wasn't easy) and were able to sperate the action from the stock. Looking at the rear end of the trigger housing, it had separated just as you describe and probably created enough space for the front not to engage properly. At this point, knowing that the unit is no longer 100% safe or reliable, I'm not going to do anything with it, save my time and money. put it down to bad design.and junk it. After seeing your post and adding in my experience , I strongly advocate anyone to take a pass on buying a Terrus with wood stock sight unseen or used, i don't know if plastic stock users have had problems ? ) Other airgun forums have also posted about issue with the "Terrus trigger unit".,, your post has the best answer out of many. I won't be picking up anything by Walther in the future, a real disappointment and shame considering their reputation.

 

[luckybuckeye]

I have one that I don’t shoot much sounds like it’s a throw away or needs some screw cups which would have to be custom made

 

[survivor45]

I have no experience with this particular air rifle. But , a suggestion for the DIY people. 
Glass , Pillar bedding. 
This is why custom rifles (powder burners)all get glass bedded with pillars. If you like this air rifle and also like to tinker with your guns. Look into glass bedding your action. 

 

[Guest]

I have no experience with this particular air rifle. But , a suggestion for the DIY people. 
Glass , Pillar bedding. 
This is why custom rifles (powder burners)all get glass bedded with pillars. If you like this air rifle and also like to tinker with your guns. Look into glass bedding your action. 

Yesh that or simply don't over tighten stock screws ... I'm thinking the problem is with "Armstrong" gunsmithing.

 

[JohnL57]

I got one for a friend-the trigger had been modded by the previous owner. While testing it I found if I pulled the trigger while the safety was on, it would fire as soon as the safety was disengaged without touching the trigger! I was able to get replacement parts from Umarex and replaced all the contact parts of the trigger group. It worked fine after that. Interestingly enough the seller said he was aware of the problem, but didn't think it was important enough to mention!

Pretty accurate gun, but suffers from 'price point' design compromises IMO. There's more to the saga of that particular rifle, but that's for another day...

 

[boggweasel]

All very well to say "don't over tighten the screws"... Stock bolts and screws on springers have to be tight, not snug but tight. , The recoil from the spring will work bolts and screws loose if not tightened sufficiently and accuracy goes out the window as the stock and action no longer function as a solid unit. When I first got my Terrus, it shot erratically, i checked the front screws and sure enough, each one benefited from a half turn, after that, accuracy was on point. The bolts causing separation of trigger unit is obviously a design flaw and I should imagine one thing that Walther couldn't check for as it seems to happen over time IMHO it should still make Umarex responsible for fixing it.as it can make the unit potentially dangerous to handle regardless of who owns or how old the gun is.Cars get recalls for things with a lot less hazardous potential,. Four Terrus owners with exact same mech problem under one topic heading ? That's quite a lot considering there must be other Terrus owners out there who don't use online sites or forums cursing their POS guns and with no idea of what to do about it. I don't know exactly what the Walther Ltd lifetime Warranty covers,but I'm pretty sure I've voided mine anyways. My mech friend managed to drill out the front bolt, on the trigger guard and replace it with a new set.and I'll be testing it out tomorrow to see whether I have a rifle or a scattergun.... one will be a keeper...and I really would like to keep it as for a while there it was a damn good little rifle. 

 

[boggweasel]

John 57, are you sure the trigger had been modified ? Using my "rescued" Terrus yesterday, not only was the trigger extremely sensitive but the gun discharged spontaneously a couple of times immediately on turning the safety off. . Could be that once the trigger unit has become separated, it makes the whole trigger assembly unstable. Maybe your friend hadn't modded the gub at all and was just passing his problem over to you. Can you take your gun out of the stock and have a look at where the two halves of the unit come together and see if there's a gap ?

 

[Moog]

Does the Walther LGU and LGV have this same problem?

 

[provels]

I got one for a friend-the trigger had been modded by the previous owner. While testing it I found if I pulled the trigger while the safety was on, it would fire as soon as the safety was disengaged without touching the trigger! I was able to get replacement parts from Umarex and replaced all the contact parts of the trigger group. It worked fine after that. Interestingly enough the seller said he was aware of the problem, but didn't think it was important enough to mention!

Pretty accurate gun, but suffers from 'price point' design compromises IMO. There's more to the saga of that particular rifle, but that's for another day...

I had same problem with mine, but no mods. Returned action for repair, they said they couldn't fix and sent me an RWS 3400 no charge. Sold the stock and sights.

RWS 3400 .177 Review - Airgun Nation