Weihrauch HW100 T has become completely inaccurate

[jepho]

I am used to a free floating barrel on my Rapids and I have run a HW100 with the clamp removed and it was fine as the barrel is located pretty firmly in the action.. Will it work? The answer is 'I don't know' but barrel clamps can get disturbed or knocked and as stated by Jon, removing it and testing is a zero-risk strategy so you might just as well do it.

A few minutes work and nil financial outlay has to be worth while. In any event if it isn't the clamp is will probably end up being diagnosed as the barrel itself which will cost you a few bob to get fixed. It is certainly also worth checking that the two parts of the action have not become loose. One of the major criticisms of the HW100 is that the block is in two parts bolted together with not particularly heavy duty 4mm hex bolts. They shouldn't be loose but again always worth checking when you have the action out of the stock.

Thank you for this helpful response and your input.

There is only one single angled grub screw holding the barrel into the action. One bolt holds the stock against the action and the bolt through the barrel band holds the fore-stock against the cylinder. I can see that the testing of the barrel without the band holds little risk and it would be worth testing the issue while the gun is shooting like a shotgun.

If my gun were to come back from the gunsmith and fund to be shooting absolutely accurately, then there would be (to my mind) less value in testing the gun in this way. I am working on the assumption that all parts of any design have a specific purpose and removing any of them can presage and unwanted effect. I did check for the integrity and tightness of the bolts holding the two parts of the action together and they seemed to be as tight as required.

Whatever may lie behind the gun failing to produce the accuracy to which I am used to seeing; I am inclined to agree with you that the issue lies within the barrel in some manner. I am prepared for the costs involved and I will try to look after my gun differently if it can prevent the same thing. For now, I have to wait and see what the gunsmith can achieve.

[Bladerunner too]

is this issue still going on, if so i will tell you what it is an that is the little washer inside the main valve ,either worn or sticking, making the gun use different amounts of air,Chrony the gun .

[Rog5]

I don't know if this has already been said, and I do realise that this isn't a spring rifle, but PCPs can also be susceptible to over/under tightening of stock screws, might be worth a look. Rog

[jepho]

I don't know if this has already been said, and I do realise that this isn't a spring rifle, but PCPs can also be susceptible to over/under tightening of stock screws, might be worth a look. Rog

Thank you. The screws were checked and they are not too tight.

[Blackmax]

Crikey, a lot of different suggestions on here.

The source of inaccuracy could be down to a number of things but most importantly, if it was at one time very accurate, without having to keep cleaning the barrel it'll be possible to return it to its former self.

Firstly let me say that a so called fussy barrel as they're described isn't a good barrel. A barrel should be able to shoot a number of pellets accurately but may have a preference that'll give supreme accuracy.

Let's start with the silencer, the HW version, a market leader, as others have said shouldn't bend, they're robustly built. Any damage would be evident on the 1/2 unf thread end by way of indentations. The silencer can be easily checked to see if pellets are clipping, remove the muzzle end with a 7mm Allen key. Inside are three chambers separated by metal washers, easy to take out and put back. The central hole is designed for 177, 20 and .22 so the former will have the greatest clearance.

The barrel; HW have recent history of producing poorly finished examples with rough internal finishes and crowns. Things just don't seem to be the same as when the Weihrauch's we use to know we're made in West Germany. The reason this causes inaccuracy is the rough finishes collect lead deposits. A proper barrel tune can often sort this out.

The internals; inaccuracy as your experiencing could well be caused by power fluctuations a chronograph would show this. The inlet valve could cause this if the ball bearing was sticking in its O ring seat. The piston could also be sticking. Dirt in the regulator washers can also cause power fluctuations. Issues with the dump valve would result in air loss down the barrel, so unless you're experiencing this it can be ruled out. A strip, clean and O ring chance will sort this as long as there's no damage.

The back block has a couple of possible causes, the first is the hammer sticking due to over zealous factory use of poor quality grease. Another possibility but a bit of a long shot is the cocking arm lever which could be slightly bent preventing a full seal with the breach. Again, a strip clean and check everything is geometrically correct will sort this out.

If of course there is a couple of these issues they could add up leading to the inaccuracy.

If you wish your welcome to pm me to discuss.

BM

[Steve C.]

Now I know nothing about HW100s, but I was talking to a fellow shooter at Kingsley this morning who had encountered a similar problem that was finally identified as being the probe not moving back and forward uniformly but putting the pellet into the breech at a slight angle. If you can put a pellet in using tweezers this can be ruled out.

Steve C.

[Lavant_Lad]

Will be interesting to learn what your elected gunsmith has to say on this rifle.

[Pman]

just a little feedback to the OP with my Hw100.

After trying about 20 different pellets I am semi settled that at least some of it is the pellet. I can pretty much do one hole at 20-25 yards. But down on our 50 yard range we are talking 1-1.5inch center to center on the grouping which is "ok" but I wouldnt have said it was fantastic. This is obviously random flier and wind pending. But it seems to like really light pellets, JSB Diablo RS lights - 13.x grain seem to be order of the day from the testing pack. H&N FTTs / pretty much everything else gives a spread of 2+ inches at 50 yeards which is not what I was expecting from a Hw100.

How much I am over expecting after getting 5p groups at 50 yards with my .177's I don't know but we shall see when the tin arrives this week.

Pete

[jepho]

just a little feedback to the OP with my Hw100.

After trying about 20 different pellets I am semi settled that at least some of it is the pellet. I can pretty much do one hole at 20-25 yards. But down on our 50 yard range we are talking 1-1.5inch center to center on the grouping which is "ok" but I wouldnt have said it was fantastic. This is obviously random flier and wind pending. But it seems to like really light pellets, JSB Diablo RS lights - 13.x grain seem to be order of the day from the testing pack. H&N FTTs / pretty much everything else gives a spread of 2+ inches at 50 yeards which is not what I was expecting from a Hw100.

How much I am over expecting after getting 5p groups at 50 yards with my .177's I don't know but we shall see when the tin arrives this week.

Pete

Hi. Thanks for the response.
I guess you must be shooting .22 with 13 grain pellets.

My own gun is .177. If I want to shoot light pellets, the RWS R10 match pellets are only 8.2 grain in weight for rifles.
I could even use the 7 grain R10s for pistols, if lightness was an issue.

For a .22 calibre gun you could try RWS hobby pellets. They are 11.9 grain so they may help your cause if lighter pellets work better.
Technically speaking, the lighter pellets should have a flatter trajectory and give you an increase in velocity. Both of these characteristics should help to improve the accuracy. I think when you are testing, there is no substitute for shooting from a solid bench-rest and indoors. That way, you have eliminated two of the common variables which will affect accuracy. Wind and gun movement.

[jepho]

Will be interesting to learn what your elected gunsmith has to say on this rifle.

You can sing that!

[jepho]

Now I know nothing about HW100s, but I was talking to a fellow shooter at Kingsley this morning who had encountered a similar problem that was finally identified as being the probe not moving back and forward uniformly but putting the pellet into the breech at a slight angle. If you can put a pellet in using tweezers this can be ruled out.

Steve C.

Thanks for the suggestion. The gun is not in my hands at the moment so I cannot check this. I did not see any problems with feeding the pellets from the magazine. Another person suggested the hand feeding test too, so it is on the cards if the gunsmith cannot assist me.

[woodpigeon]

Crikey, a lot of different suggestions on here.

The source of inaccuracy could be down to a number of things but most importantly, if it was at one time very accurate, without having to keep cleaning the barrel it'll be possible to return it to its former self.

Firstly let me say that a so called fussy barrel as they're described isn't a good barrel. A barrel should be able to shoot a number of pellets accurately but may have a preference that'll give supreme accuracy.

Let's start with the silencer, the HW version, a market leader, as others have said shouldn't bend, they're robustly built. Any damage would be evident on the 1/2 unf thread end by way of indentations. The silencer can be easily checked to see if pellets are clipping, remove the muzzle end with a 7mm Allen key. Inside are three chambers separated by metal washers, easy to take out and put back. The central hole is designed for 177, 20 and .22 so the former will have the greatest clearance.

The barrel; HW have recent history of producing poorly finished examples with rough internal finishes and crowns. Things just don't seem to be the same as when the Weihrauch's we use to know we're made in West Germany. The reason this causes inaccuracy is the rough finishes collect lead deposits. A proper barrel tune can often sort this out.

The internals; inaccuracy as your experiencing could well be caused by power fluctuations a chronograph would show this. The inlet valve could cause this if the ball bearing was sticking in its O ring seat. The piston could also be sticking. Dirt in the regulator washers can also cause power fluctuations. Issues with the dump valve would result in air loss down the barrel, so unless you're experiencing this it can be ruled out. A strip, clean and O ring chance will sort this as long as there's no damage.

The back block has a couple of possible causes, the first is the hammer sticking due to over zealous factory use of poor quality grease. Another possibility but a bit of a long shot is the cocking arm lever which could be slightly bent preventing a full seal with the breach. Again, a strip clean and check everything is geometrically correct will sort this out.

If of course there is a couple of these issues they could add up leading to the inaccuracy.

If you wish your welcome to pm me to discuss.

BM

hi mate you say they are not made in west germany anymore,where did they move to?

[Blackmax]

hi mate you say they are not made in west germany anymore,where did they move to?

Well, when the Berlin Wall came down in the 90's they became Germany rather than West Germany.

German engineering has always been top of the pile along with Swedish and post war English but it's just not the same now.

What you can get assured of is the designs are absolutely top of the tree it's just the QC isn't what it was, but with a little attention to detail it can be put right.

For me the ultimate hunting gun no matter what cost is an HW100 in .20, nothing to match it.

[danco1987]

hi mate you say they are not made in west germany anymore,where did they move to?

I think he's referring to the quality of old back before the unification of Germany.

[jepho]

Crikey, a lot of different suggestions on here.

The source of inaccuracy could be down to a number of things but most importantly, if it was at one time very accurate, without having to keep cleaning the barrel it'll be possible to return it to its former self.

Firstly let me say that a so called fussy barrel as they're described isn't a good barrel. A barrel should be able to shoot a number of pellets accurately but may have a preference that'll give supreme accuracy.

Let's start with the silencer, the HW version, a market leader, as others have said shouldn't bend, they're robustly built. Any damage would be evident on the 1/2 unf thread end by way of indentations. The silencer can be easily checked to see if pellets are clipping, remove the muzzle end with a 7mm Allen key. Inside are three chambers separated by metal washers, easy to take out and put back. The central hole is designed for 177, 20 and .22 so the former will have the greatest clearance.

The barrel; HW have recent history of producing poorly finished examples with rough internal finishes and crowns. Things just don't seem to be the same as when the Weihrauch's we use to know we're made in West Germany. The reason this causes inaccuracy is the rough finishes collect lead deposits. A proper barrel tune can often sort this out.

The internals; inaccuracy as your experiencing could well be caused by power fluctuations a chronograph would show this. The inlet valve could cause this if the ball bearing was sticking in its O ring seat. The piston could also be sticking. Dirt in the regulator washers can also cause power fluctuations. Issues with the dump valve would result in air loss down the barrel, so unless you're experiencing this it can be ruled out. A strip, clean and O ring chance will sort this as long as there's no damage.

The back block has a couple of possible causes, the first is the hammer sticking due to over zealous factory use of poor quality grease. Another possibility but a bit of a long shot is the cocking arm lever which could be slightly bent preventing a full seal with the breach. Again, a strip clean and check everything is geometrically correct will sort this out.

If of course there is a couple of these issues they could add up leading to the inaccuracy.

If you wish your welcome to pm me to discuss.

BM

Thank you for your comprehensive and informative post.

Given the previous 18 months extreme accuracy, I think it reasonable to assume that the barrel did not start out being poorly made. I finally checked the moderator myself. I could see no build up of lead nor any signs of pellet clipping. It was confirmed by exchanging the silencer for a brand new Huggett model; which made no difference to the poor accuracy issue. Additionally the gun was fired without any moderator and the shotgun pattern was still evident.

I could not get several series of ten pellets to show any substantial fps variations nor was the muzzle energy unexpected for the pellet weights and recorded velocities. With no power fluctuations, I am at a loss as to how I can understand the mechanism by which the pellets are not being delivered as expected. I think a full service is probably called for because after 18 months of weekly use, the gun could probably do with it.

When I removed the barrelled action, there did not appear to be any impediment to the hammer by way of a surfeit of grease. The cocking leaver appears to be the correct shape and is very smooth in its action. Thanks for the heads up about the breech not being sealed correctly with an out of true cocking lever.

Thank you for your kind offer of a PM conversation. I don't want to waste your valuable time just because I know SFA about guns. I believe the gunsmith (where the gun is was delivered) is a member of this BBS, so he may be able to further shed light on the issue for the benefit of the membership.

My short term answer is to wait and see what is revealed. I suspect now that a dirty barrel is still the culprit in some way that I do not understand as yet. I think some lead splash has attached itself to the rifling and is imparting a twist to the pellets. This would account for the random hits. I will try and film them in slow motion after I get the gun back.