Weihrauch HW100 T has become completely inaccurate

[angrybear]

Thank you for your time and the valuable response. In engineering terms, I don't understand pellet fussy as a description. If that means that Weihrauch makes a barrel that is set to handle different pellet configurations in different ways, then the parameters used to manufacture the barrel are known and the best pellet for that specific configuration of the barrel is also a known. Knowing how German engineering tends to handles issues, I would expect Weihrauch to understand barrel variation and the implications of each standard deviation barrel from the expected norm.

Hitherto, all of my pellet choices have demonstrated and underlined the accuracy of the HW100... so much so that my son called it "cheating", every time I used the gun; regardless of the pellets I used. For now, I have left the gun with a highly recommended gunsmith and will report back to the thread once I know what the problem is and how it was solved. As a scientist and an engineer, I want to learn about the explanations that make sense to me. Feelings and beliefs have no place in my world and all things are explicable.

Since the problem began, I have used just about every high quality pellet available and still I am not seeing any improvement. This fact alone suggests that pellet choice is not responsible for creating the problem. For the sake of furthering the debate, if we accept the assumption that all pellets are different, then I should have seen an improvement representing consistency, even if the group was orange sized when I changed my pellets. No such improvement in consistency has been seen. All pellets produce the shotgun patterns shown.

It means just what it says, the barrel is extremely fussy about what it will shoot accurately, in an extreme case it can mean that with the same make & size pellet it will be super accurate with pellets from one batch or die press, but pellets from a different batch or die press are hopeless.
My .25 rapid will single hole with JSB like your pic1, but with any other pellet is like your pics 2 & 4, thankfully it's not batch fussy within JSB.

Are your pellets the same batch now as when it shot that single hole ??

[Luftgewehr100]

I will take the gun back to the gunsmith today.

Good decision!
Please keep us informed if he managed to solve the problem.

[old goat]

Thanks AngryBear!

[Shedder]

Hope the gunsmith fixes it.
Have you tried individually loading pellets manually without the magazine? If the mags are slightly out of alignment it may result in some damage. The mags may be perfect, but fo they align perfectly?
Worth a try with a pellet like H&N FTTs that usually shoot well with HW100s.

Or you could try shooting into a very deep bucket or barrel of water and retrieving pellets to look for signs of shaving. It does need to be very deep though (probably >24 inches) because otherwise the pellets deform when they hit the bottom.

[jepho]

It means just what it says, the barrel is extremely fussy about what it will shoot accurately, in an extreme case it can mean that with the same make & size pellet it will be super accurate with pellets from one batch or die press, but pellets from a different batch or die press are hopeless.
My .25 rapid will single hole with JSB like your pic1, but with any other pellet is like your pics 2 & 4, thankfully it's not batch fussy within JSB.

Are your pellets the same batch now as when it shot that single hole ??

Thank you for your response. The pellets are now from a different batch, which shot well before they did not.

The fussy barrel notion still has me confused. My understanding is that the barrel is a convenient piece of tempered metal which is drilled to a convenient size and it may or may not be rifled. It will be a tube of known hardness and dimensions and finished to a known surface smoothness. It will not tend to flex and machining it should produce a similar resonant frequency for 100% of the samples tested. If the variation in the finished size of the drilled hole is uncontrolled, the barrel will be as near to unfit for purpose as it is possible to make. I suspect that the tolerance of the drilled hole is very tight for the nominal calibre.

In my early days, I would have to make products (without laser guidance or cutting) using ordinary machine tools. I worked to plus two ten thousandths of an inch and minus nothing. That was high precision back then. Today, the highest precision can be obtained with CNC and lasers or water jets. I assume that high precision work is far better today than it was when I first planned and cut a cam or produced a gear wheel or screw thread.

Given my assumptions (if correct) about barrel production for manufacturers such as Weihrauch, Walther, Feinwerkbau and Anschütz, I don't understand how an inanimate piece of metal (with a hole in the barrel that is nominally .177) can be fussy about which pellets it can use. It is also notable that we tend to find German engineering to be of the best quality. My HW100 appears to like all of the pellets with which it has been fed and I have an expectation that this would be the normal use case. Likewise; my Air Arms Alfa Pro J pistol for 10 metre work, does not appear to mind which pellets it is fed with. I tend to keep using the R10s but have had similar results with H&N FTTs, Bisley Practice and JSB Exacts. In absolute quality terms, I find the R10s excellent for QA. Using them means my lazy self has one less job to do.

[jepho]

Good decision!
Please keep us informed if he managed to solve the problem.

Yes, I happen to think so too. Thank you for your response. I don't know enough about guns and gunsmithing to effect any of the necessary repair work myself. I have tools and a space to use them. I have very little understanding of common issues. As the problem appears to be rather difficult to pin down and has already defeated one experienced gunsmith, I need to use the expertise of a person who has a vast experience and dealt with a similar problem previously. My guesswork as to what may be wrong is just clouding the issue.

[jepho]

Hope the gunsmith fixes it.
Have you tried individually loading pellets manually without the magazine? If the mags are slightly out of alignment it may result in some damage. The mags may be perfect, but fo they align perfectly?
Worth a try with a pellet like H&N FTTs that usually shoot well with HW100s.

Or you could try shooting into a very deep bucket or barrel of water and retrieving pellets to look for signs of shaving. It does need to be very deep though (probably >24 inches) because otherwise the pellets deform when they hit the bottom.

Me too. Thanks for your useful input.

I have not tried manually loading pellets... I had not thought about it. Now that I do consider it, I was wondering if it would make the possibility of misalignment of the pellet, at the breech end, much more likely. The magazine presents the pellet to be loaded and after the magazine is indexed, the loading is carried out by a pin which pushes the pellet along the axis of the barrel. If that pellet is misaligned during that push part of the loading cycle, it could possibly exhibit some perturbation as it receives the air that pushes it out of the barrel. That could be one reason why all pellets are not grouping whereas previously; all of the pellets did group well. I can ask the gunsmith to look at that issue; thank you for the thought.

I also like the simple idea of test firing the pellets into a body of water in order to see what potential shaving marks are visible. This is another idea I can usefully adopt when my gun is returned to me. Thank you for your assistance.

[Pman]

I'll be interested to see your results. I am having problems with my newly acquired .22 100T - It seems to be ok out to about 20yards anything beyond that and we are geting 2inch groups

Brought a JSB testing pack to fly through it tomorrow - lets see what happens.

[jcooper]

When your barrel was loose originally and before it was tightened you/ or gunsmith probably rotated it slightly while removing/refitting old/new moderator.

The barrel is probably not in its optimum position. One way to check this is to shoot at a single aim pointon a plain paper target 10 yards away with a slighly loose barrel (so you can just rotate it ). Turn the barrel in small increments and shoot at same point you should produce a curve of some sorts in the card( a full rotation should get some thing like an oval). The barrel will be correct when either at the very top (or very bottom ) of the curve. mark then tighten and recheck.

I had a similar problem to you and this is how I cured it hope this helps. BTW I have also removed the oring on the barrell band ( free floated ) as this can cause similar problems if barrel has been knocked.

good luck

John

[Geezer]

Most guns of good quality shoot a wide variety of good quality ammunition adequately well.

Sometimes, you will find a belter that shoots a significant number of good projectiles very well. You keep those ones.

Sometimes, you find a gun that shoots very well with only one or two types. Those are “pellet fussy”.

It happens. It isn’t always down to the barrel, other factors are involved: bedding, harmonics, start pressures, etc, etc.

But quite often, it does appear to be the barrel. You isolate or modify as many as possible of the other factors, and nothing changes.

Jepho: your points are well taken, but I fear you overrate the consistency of barrel production in airguns. Or most firearms for that matter. The vast majority of civilian guns are built down to a price.

There’s no doubt that (e.g.) LW make good barrels, but most airgun barrels are not at that level, and HW100s have definitely in the recent past had issues with poor quality ones. A near-perfect barrel (e.g. for CF benchrest or military sniping) costs anything from £200-300. No air gun maker will spend that. Well, maybe for really high-end Olympic match stuff, but not for anything less.

Bottom line: sometimes you get a lemon.

[Lavant_Lad]

Most guns of good quality shoot a wide variety of good quality ammunition adequately well.

Sometimes, you will find a belter that shoots a significant number of good projectiles very well. You keep those ones.

Sometimes, you find a gun that shoots very well with only one or two types. Those are “pellet fussy”.

It happens. It isn’t always down to the barrel, other factors are involved: bedding, harmonics, start pressures, etc, etc.

But quite often, it does appear to be the barrel. You isolate or modify as many as possible of the other factors, and nothing changes.

Jepho: your points are well taken, but I fear you overrate the consistency of barrel production in airguns. Or most firearms for that matter. The vast majority of civilian guns are built down to a price.

There’s no doubt that (e.g.) LW make good barrels, but most airgun barrels are not at that level, and HW100s have definitely in the recent past had issues with poor quality ones. A near-perfect barrel (e.g. for CF benchrest or military sniping) costs anything from £200-300. No air gun maker will spend that. Well, maybe for really high-end Olympic match stuff, but not for anything less.

Bottom line: sometimes you get a lemon.

Im with Geezer on this one !!!!!!!!!

[jepho]

When your barrel was loose originally and before it was tightened you/ or gunsmith probably rotated it slightly while removing/refitting old/new moderator.

The barrel is probably not in its optimum position. One way to check this is to shoot at a single aim pointon a plain paper target 10 yards away with a slighly loose barrel (so you can just rotate it ). Turn the barrel in small increments and shoot at same point you should produce a curve of some sorts in the card( a full rotation should get some thing like an oval). The barrel will be correct when either at the very top (or very bottom ) of the curve. mark then tighten and recheck.

I had a similar problem to you and this is how I cured it hope this helps. BTW I have also removed the oring on the barrell band ( free floated ) as this can cause similar problems if barrel has been knocked.

good luck

John

Thanks for the points John. I doubt that the barrel was ever loose but your tip for aligning it correctly is well worthwhile. I have no confidence in the gunsmith who told me that the Weihrauch moderator was bent out of true. Hopefully all will be made well again once my formal gunsmith has a look.

[jepho]

I'll be interested to see your results. I am having problems with my newly acquired .22 100T - It seems to be ok out to about 20yards anything beyond that and we are geting 2inch groups

Brought a JSB testing pack to fly through it tomorrow - lets see what happens.

Thank you for your response: I will feed back my results as soon as I have something to report.

I am not as knowledgeable as I would wish to be. Is your 100T a new gun or just new to you? The distance of 20 yards requires some ballistic knowledge to analyse correctly. My intuition is that if 20 yards is accurate, there is no reason why 40 yards could not be accurate. I am sure someone will be along soon to tell me why that is foolish assumption but it may open a helpful debate on what is not working for your gun.

[jepho]

Most guns of good quality shoot a wide variety of good quality ammunition adequately well.

Sometimes, you will find a belter that shoots a significant number of good projectiles very well. You keep those ones.

Sometimes, you find a gun that shoots very well with only one or two types. Those are “pellet fussy”.

It happens. It isn’t always down to the barrel, other factors are involved: bedding, harmonics, start pressures, etc, etc.

But quite often, it does appear to be the barrel. You isolate or modify as many as possible of the other factors, and nothing changes.

Jepho: your points are well taken, but I fear you overrate the consistency of barrel production in airguns. Or most firearms for that matter. The vast majority of civilian guns are built down to a price.

There’s no doubt that (e.g.) LW make good barrels, but most airgun barrels are not at that level, and HW100s have definitely in the recent past had issues with poor quality ones. A near-perfect barrel (e.g. for CF benchrest or military sniping) costs anything from £200-300. No air gun maker will spend that. Well, maybe for really high-end Olympic match stuff, but not for anything less.

Bottom line: sometimes you get a lemon.

Thank you for your helpful response. In relation to my own situation; my gun would shoot accurately with many different types of pellets. The recent loss of accuracy is baffling. The rifle is stored in a hard case and it has never been dropped or mistreated. The accuracy loss up to the point where no pellet POI can be predicted and the pellets can end up anywhere on a 6.5 inch target face despite the same point of aim and a rock steady hold, is difficult to explain. The pellet direction on leaving the barrel would be north, south, east or west and all points in between. I had thought that there was some accidental damage to the crown but nothing can be seen on close inspection. I don't see how the concept of the barrel being pellet fussy applies in this particular case. Before the deterioration of accuracy, I could use any pellet and produce reasonable groups.

I take your point about the production of barrels and the likelihood of getting a good one. My intention is not to concern myself with what sounds as if it may be a dark art of tuning for specific manufacturer created barrel faults. I will soon be buying an Anschütz 9015 for ten metre work and then I would like to buy another for longer distance work. I don't want to be bothered with ironing out deliberate faults (compromises) in gun manufacture. Life is too short and I want to be able to shoot without trying to correct bad decisions made at the design stage of a gun. I suspect this the principle rationale behind the often high cost of olympic standard guns.

As for lemons... my gun was not a lemon on purchase 18 months ago and there is no obvious reason for it to have become a lemon now. I would prefer to have it working well and if that cannot be done, then it will be handed on to someone who is prepared to work with it. To me, a gun that cannot place the projectile where it is pointed is useless... it is not a gun in any sense of the word which I can trust and understand.

[jepho]

Im with Geezer on this one !!!!!!!!!

i have yet to be convinced. 😁