Tuning HW100 Loose Barrel | Tightened Grub Screw but Bad Performance Now

[viperhawk]

I have a couple of newer HW100's but recently purchased a used HW100TKL that must have a bonded/glued moderator (older model).

I gave the moderator a twist this evening so I could remove it to clean the barrel. It ended up slightly turning the barrel. I cleaned the gun with the moderator in place.

I removed the stock and cylinder to give the barrel grub screw a slight turn to tighten the barrel a bit.

Pellets are all over the place after putting it back together and it doesn't seem to be leading in.

Should I change the 2679 barrel breech connector o-ring? It's holding air otherwise.

 

[elh0102]

It's not necessarily an old model, I believe all the ones brought into the US have bonded moderators. I bought two recently, had to heat up both of them to break the epoxy and unscrew the silencers. I suggest you remove the barrel and give it a good cleaning, you can easily verify the O ring at the end of the barrel. Maybe you did this, your post wasn't clear about whether you removed the barrel. You could also check the breech seal O ring. When you turned the barrel in place, I wonder if it's possible that you left an uneven seating surface for that grub screw, or even broke it. Or, could you have gotten the silencer out of alignment to cause clipping? It could possibly be bent at its base plate connection to the muzzle by leverage applied while on the barrel. Shooting it without the silencer attached would reveal any such problem. My .177 HW100 was shooting poorly yesterday, I removed the barrel and cleaned it, and the accuracy is 100% back now. These rifles are generally bullet proof, and that kind of accuracy problem would generally suggest a dirty barrel. Was it shooting well before? Used rifles sometimes present surprises.

 

[thumper]

I'll bet the barrel just isn't leaded in, or doesn't shoot well clean with whatever pellets you are using. It happens. 

I've spun the barrels completely around in my HW100s while shooting groups, checking for the highest POI and the groups never really suffered. Seriously doubt you did anything there.

It's worth checking that breech seal though. Open the bolt, shine a light down the muzzle and you can see it easily. 

 

[elh0102]

Regarding the breech seal, with such a small breech opening, detailed 360 degree visibility can be a challenge. If you drape a piece of tissue over the closed breech and fire it, you will know immediately if there is a leak there. But I think the issue is the barrel, either still dirty, or not yet seasoned from the cleaning. But frankly, I've never seen mine need more than a few shots to come back after cleaning.

 

[dizzums]

dont know the design on that gun, but i wouldnt 'over' tighten grub screws on a barrel .. just because you can fwist it with a moderator as a handle doesnt mean it needed to be tightened .. on a thinner barrel with a beefy set screw i imagine its possible to actually deform it ..

 

[KatoKevin454]

get a 7mm allen wrench and remove the end of the Moderator, remove the internals of it there should be 2 baffles and a washer, check the baffles for any obstruction, test the accuracy with the moderator internals removed, if it returns to be accurate then the problem is clipping or an obstruction, it only takes a few loose fibers of felt too cause the pellet to loose accuracy, you can heat a steel rod with a torch or fire and shove it through the Baffles very Quickly to melt any loose felt strands, make sure you do this with the baffles out of the moderator, there is a chance you over tightened the barrel grub screw causing the barrel to bend or crush the seals, the grub screw only needs about 5-10 inch pounds of torque, so just snugging it would be good, try loosening the grub screw and re-snugging the grub screw and also do the tissue test to make sure the breech and barrel seals are not affected.

when cleaning Remove the Moderator internals as described above, this should prevent any lint or strands of material from getting caught in the Stainless steel Baffle screens.

 

[viperhawk]

I've removed the moderator end and internals. Will report back.

 

[viperhawk]

This is resolved

I cleaned the barrel again

Replaced the barrel o-ring

Removed the moderator baffles and reinstalled.

Swapped back to my H&N FTT’s

Perfect now

 

[KatoKevin454]