HW100

[IanB 0]

Alright lads, I'm not an air rifle guru like some of you one here, but recently done a deal with a work mate and got a couple of guns, fill kit and a small walther as well...

 

The HW100 has a silencer with a red sheen to it, I'm not sure if these are original as this was probably one of the first HW100's that came out, or its a different one been added...

 

Also when the air cylinder is screwed in the pressure drops over a few hours by say 5 bar progessively dropping further.. I changed the five main seals, but it still appears to be dropping as before, its fine if left screwed out and used as required... Any suggestions ?

[Sweeney-Todd 208]

Hi Ian.

 

Silencer.....not a clue mate to be honest.......looks like an AA

Check the cylender seal AGAIN mate, and when you screw it back on the rifle dont overtighten it.

Also look to see if the cylender is being obstructed by the inside of the stock at all, preventing the cylender going all the way home.

 

If that does not work, empty the cylender completely using the tool provided.

Then fill, with bursts of air, empty again, and fill properly.

 

Could be a bit of muck in the filling valve.

 

Bill.

[whistler1 26]

If you have replaced the small 0-ring,whare the cylinder screws into.

Screw the cylinder in like you would normaly do.Soon as you here the air beginning to escape,give it a

half turn or less anti clockwise.I had to do that with mine.Even when charging it.

Silencer looks like the first one put on the earlier hw100.

 

HTH

Brian

[IanB 0]

If you have replaced the small 0-ring,whare the cylinder screws into.

Screw the cylinder in like you would normaly do.Soon as you here the air beginning to escape,give it a

half turn or less anti clockwise.I had to do that with mine.Even when charging it.

Silencer looks like the first one put on the earlier hw100.

 

HTH

Brian

 

Tried this and it pissed air out, dropped 50barg so I unscrewed it fully... Its something really simple, I'll have a play, when I get more time... I asked the lad and he reckons when he bought the gun new from blackpool air rifles it came with that silencer on, he probably bought it when they first came out, hes only shot paper targets, I checked the power and it was 9.5ft/lb so I tweaked it up a tad...

[J Darcy 5,871]

Ian, the HWmk1 is renowned for this fault. Thats why i sold mine. Never coud quite get to the bottom of it and i must say i was shocked that such a quality gun house such as HW would have released guns with such a fault. I can remember when they first came out there was quite a few of us with the same problem. Best way to solve it is to sell it IMO. Nive gun though, and the best mag system i have ever used.....

[IanB 0]

Yes its quality, shame though, its not major, just drops pressure when left screwed in by about 5 barg an hour....

I phoned Hull Cart up the other day and they said they've had no problems before....urrrrrrrr yeh ok , also said £60-£100 for service, Its prob only one seal, so I'll sort it, rather than ship back and forward, etc...

[J Darcy 5,871]

Keep us informed mate when you trace which seal is leaking.

[davyt63 1,839]

hi Ian

the HW100 is a cracking air rifle,i had use to own one and it was fine!the only air it lost was when i took of the cylinder to fill,and replace it.it releases a bit of air as it goes on and off any ways!

 

is this the problem your having? if so its normal

 

but if you would like to find out,what it is you may get better answers here

 

http://weihrauchowners.freeforums.org/index.php?EBTX_notify=login&sid=9b86feb00c023a8b69ec51cf1b1904d5

 

a nice bunch of lads

 

also now you have an air rifle,i guess we will be seeing you at the THL air gun meet

 

http://www.thehuntinglife.com/forums/topic/180474-thl-air-gun-section-meet/

 

regards

 

Davy

[craig33 10]

hi pal have you changed the oring were the cylider screws on to there is a little one there that causes alot of lost air

the silencer is the mk1 standard one should come of with heat if you dont like it

[Buster321c 1,010]

HW 100 Improvements

 

 

The main culprit:

 

The breech block is sealed with a large 12x1.2 O-ring. For some reason HW have opted for a crush installation. The O-ring is pinched between breech block and action acting like a gasket seal, however, this prevents the two parts from mating properly and also allows some movement. This is perhaps only a couple of thou, but it's enough to cause problems, e.g. loose barrels (made worse by excess oil) sticking magazines and slow leaks. The O-ring is effectively destroyed upon assembly. Hans Weihrauch made a comment regarding an O-ring that always needs replacing during a stripdown, he didn't say which, but this is the one. Simply replacing this O-ring with a 12 x 1 and degreasing the front half of the action, including barrel and grubscrew (there's a lot of oil in this area) together with careful reassembly, will ensure you'll never suffer any of these issues again.

 

 

With the valve cap/breech block removed it's worthwhile making a quick inspection of the following:-

 

1. Check the valve seat for damage. Any scratches can be removed by catching a wad of Scotchbrite (grey/fine) or 000-0000 steel wool in the chuck of a twist drill and applying it with light pressure to the valve seat. The valve can also be cleaned by catching its stem in the drill and applying a wad of abrasive by hand. Be very gentle and try not to change the angle of the beveled edge/sealing face. Only perform this operation if the valve has scratches or debris embedded in its surface. Clean with a paper towel, lint free cloth or use a blast of air from your tank.

 

2. Valve return spring has closed and ground ends that can be quite rough. If you like you can polish the ends of the spring with 1200 grit wet or dry paper.

 

Make sure all the above components are absolutely clean and dry before refitting them.

 

3. Inside the breech block are two O-rings which seal the valve stem and pellet probe/bolt. These will only leak during the firing cycle and are not responsible for any slow leaks or loss of pressure(sizes listed below). A good tip for fitting the probe O-ring is to push a cleaning pellet up to the groove and manoeuver the O-ring into place from the opposite side.

 

The new main seal, 12 x 1, sits nicely in its groove and deforms under air pressure to seal, as an O-ring should.

 

Ensure securing bolts are free from excess oil and clean the threads with a brass brush. The breech block can now be properly secured and the main seal O-ring can even be reused, should you strip the rifle in future. Clean all oil from the barrel, barrel channel and grub screw. Make sure the grubscrew is dry and its threads are clean. The barrel can now be secured against the breech block - use the short end of an allen key to finger tighten it - the barrel will not loosen until you want it to. Do not use too much force when fitting a silencer. It seems the loose barrel issue worsened with the introduction of the screwcut MKII with heavy handedness when fitting a silencer being partly responsible. (Note: there is a trade off here, having the barrel and various securing bolts dry increases the risk of corrosion. An occasional visual inspection is recommended.)

 

Inconsistent power:

 

The heavy grease HW use on the hammer doesn't help re: varying power. Consider that most PCP's run with a dry hammer. This grease is dissipated through use, may be thinned if a lighter oil is introduced or changes in temperature can affect its viscosity. All affect the force with which the hammer strikes the firing valve. Degrease and lube the hammer and shuttle with a thin oil as it's steel on alloy. I'd also recommend cleaning up both to remove rough edges. Chuck up the hammer/shuttle in hand drill and give it a quick spin applying light pressure with 1200grit wet/dry. The hammer has a single circular bearing surface just in front of the rear spring guide/pip. You don't need to mirror polish either part.

 

On to the main valve; removed from the action with a deep 10mm socket, this valve consists of five components. Two threaded brass parts that make up the valve body and inside, a 4mm ball bearing (regulating valve) a spring and an O-ring. This O-ring is used to seal the two halves of the valve body. This O-ring doesn't appear on any parts diagrams/lists, size is 2x2. IMO this has too large a cross section and is pinched between the two halves of the regulator valve body reducing ID further. This reduced ID can interfere with the consistent seating of the ball bearing regulator valve. Simply replace it with a 2.57x1.78 (#005). Ensure the ball bearing is free from debris and grease/moisture from fingers. The O-ring is probably best fitted dry. The valve only needs to be re-assembled finger tight and just nipped up when replacing it in the action.

 

Igor Jelenski, who first suggested this mod, recommends trying a 3mm ball bearing and a stronger spring. If you\'d like to experiment with this I would also suggest sleeving the spring retaining portion of main valve with some 1/2mm PTFE sheet to keep the ball bearing centralized.

 

The regulator piston O-ring will, over time, take a compression set. As this is a dynamic seal this will result in leaks and erattic performance. It's simple to replace, the size is 7x1.5, same as main valve outlet.

 

Fine tuning:

 

You can make your own regulator output tester quite easily using a 1/8 BSPP female - 6x1 male tapered adapter. My gauge is from MDE and is 1/8 BSPP back entry. The male thread on the adapter is self sealing (if this isn't the case use some PTFE tape on threads). Drop an O-ring, 5.28 x 1.78 (#009), into the adapter before fitting the gauge. It should seal finger tight .

 

To use a pressure tester you'll need to remove the ball bearing from the test port located under a grubscrew. If it's stuck it can be pushed through from the inside with a small allen key (remove reg valve and piston to access it and be careful not to scratch the action).

 

Belleville washers that control the regulator\'s output can be quite dirty and may benefit from a clean and very light lube, just wet between fingers with a light oil. Stack as follows (())(())(())(())

 

The factory setting for the regulator output is approx 90 BAR. A slightly higher output pressure coupled with less hammer spring tension can increase shot count (lots of testing and patience required here) as valve duration is reduced as are the effects of hammer bounce. The increase is subtle and each gun is different. Barrel length and calibre also have to be taken into account, but off regulator velocity spikes can be avoided. Otherwise just stick to 90 BAR. If you don't have a pressure tester, make a note of the regulator's spring tension adjuster position before dismantling. Mark the 12 o'clock position on the screw (Tippex or WHY) and count the number of turns to remove it. Alternatively, measure the depth of the adjuster screw relative to the action. On my rifle, 90BAR is 2.82mm.

 

Finally:

 

It's worth noting if your gun loses pressure when stored and you're unsure of the source of the air loss, all slow leaks on the action can be fixed with 5 O-rings in just 3 sizes.

 

12 x 1 Breech block (once fitted it's unlikely this will leak again)

7 x 1.5 Regulator piston and main valve outlet

2.57 x 1.78 (#005) Main valve inlet and internal

 

Use pure Silicone grease on all O-rings except the main valve internal.

 

Tip: When removing old O-rings push a pin into the O-ring itself or use a new razor blade and be careful, don't try and dig under the seal as you may scratch the sealing surfaces.

 

Here's the full list of factory O-rings and the two recommended alternatives (bolded)

 

O-ring HW 100, 37.1 x 1.6 Cylinder clamp 2682C

O-ring HW 100, 15.6 x 2.5 Barrel clamp 2682B

O-ring HW 100, 32 x 2 Magazine 2603A*

O-ring HW 100, 13 x 2 Adaptor A 2704

O-ring HW 100, 2.57 x 1.78 Adaptor B 2703B

 

O-ring HW 100, 3 x 1.5 Valve stem 2655D

O-ring HW 100, 12 x 1.2 Breech block main (12 x 1) recommended 2658

O-ring HW 100, 5.5 x 1 Breech/probe seal .22 2659A*

O-ring HW 100, 4.5 x 1 Breech/probe seal .177 2659A*

O-ring HW 100, 4 x 1.5 Probe buffer 2618A*

O-ring HW 100, 2.57 x 1.78 Main valve inlet 2665D

O-ring HW 100, 7 x 1.5 Main valve outlet 2666

O-ring HW 100, 2 x 2 Main valve internal (2.57 x 1.78) recommended N/A

O-ring HW 100, 7 x 1.5 Regulator piston 2668

O-ring HW 100, 10 x 1.5 Tension adjuster (sometimes omitted) 2672

O-ring HW 100, 8 x 1.5 Barrel 2679

 

FX/V-Mach Probe, 5.28 x 1.78 PUR70

 

Buster .

[davyt63 1,839]

:icon_eek:

[Sweeney-Todd 208]

Hi Ian.

 

Might pay to send it away to ADI at A&M Gunsmiths.

For about £120 he will sort it for you.

 

He has just finished mine.

 

Lapped the crown.

Balanced and set the reg pressure and hammer tention.

Decreased the lock time.

Set the Ftlbs to what I wanted.

Improved consistancy dramaticly.

Added extra grub screw to hold the barrel.

Also other work to the internals.

 

Cant reccomend the guy enough, a chat to him on the phone will put your mind at rest.

Unless of course you know your way around the internals of the HW100 yourself.

Could save you time and more money in the long run mate.

 

A&M Gumsmiths......Adi.....01623 861308.

 

 

Just a thought.

 

Bill.

[J Darcy 5,871]

Just for the record, my 100 was brand new when it had this fault, as were other peoples at the time when they got the mk1

[IanB 0]

If you have replaced the small 0-ring,whare the cylinder screws into.

Screw the cylinder in like you would normaly do.Soon as you here the air beginning to escape,give it a

half turn or less anti clockwise.I had to do that with mine.Even when charging it.

Silencer looks like the first one put on the earlier hw100.

 

HTH

Brian

 

Tried this the other day and lost about 40-50barg pressure instantly... Just had time to check it and the #005 O ring has been torn on one side by doing this...just replaced it and all good...I'll monitor again for leaks..grrrrr

[IanB 0]

Just tried another breech seal and lubricated with silicon grease, also greased the valve stem o ring thats a slightly larger internal diameter than the #005 seals and it seems to have stopped any minor pressure dropping.... bonus..