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A & M Custom Weihrauch HW100 Cylinder Review

A & M Custom Weihrauch HW100 Cylinder Review

I've been thinking about replacing my standard steel air cylinder on my HW100KT for the aluminium version made by A&M Custom Gunsmiths for quite a while. In fact, I've heard nothing but good things about these cylinders, and how good their customer service is.

However, £140.00 inclusive (04/11/12) is a price that makes you think long and hard, especially for what's just a replacement of something that's perfectly serviceable! Of course many owners sell their original which can offset the majority of the price.


Fortunately my birthday was at the end of October, so with kind contributions from family members I decided to take the plunge. My cylinder arrived very quickly in the post in a very nice and smart satin black anodised finish, complete with instructions and a little zip lock bag with the probe and spare "o" rings.

The company is in fact home-based, the owners being Adrian and Mandy, and the A&M quick fill cylinders are hand made in a small but fully fitted workshop in the back garden.

The clyinders are checked very carefully at each stage of production, finally being filled to 200 bar and left for 48 hours before being emptied and delivered. There is a safety feature built into the design should the cylinder be overfilled beyond 200 bar, as before it reaches a critical level an "o" ring will blow and the air will escape from a section built into the tube about 30mm from the gauge.

As my .177 HW100 is the Carbine version obviously all dimensions etc. will be based on this gun. The rifle version is naturally that little much bigger.

Carbine A&M Cylinder Weihrauch
Weight: 0.332kg 0.630kg
Length: 245mm 222mm
Diameter: 37mm 35mm

This slightly greater difference in size, plus internal differences gives a reported difference in shot count of approximately 50%. Results vary from gun to gun naturally, but as an example, the Carbine version will probably give you two magazines more giving a total of six magazines per fill as opposed to four with the Weihrauch original, that's 84 pellets instead of 56!

I should say at this point that before I fitted the A&M cylinder I had a real chance to compare it with the Weihrauch. There's nothing like hefting the two to immediately notice the difference. I don't think you appreciate just what that is until you feel it as a dead weight in your hand. As you can see above the A&M aluminium cylinder comes in at half the weight of the Weihrauch.


Once fitted to the gun you really notice straight away how better it handles. All the weight that was barrel end has now been reduced giving a better centre of gravity towards the trigger. I immediately felt the difference. At this point I decided a change of scope was in order. Previously I had a Hawke Sidewinder mounted, and I replaced this with the much lighter Hawke Panorama EV. Previously the Sidewinder/Weihrauch combination added up to over 3.5lbs. This weight has literally been halved! The result is amazing.

Having removed the original HW cylinder from my gun, for safety I used the handy heavy brass fitting supplied with the gun that allows you to bleed off the remaining air in the cylinder. And this is the only disadvantage the A&M cylinder has, as once fitted and filled it can't be removed without reducing the pressure to 100 bar and letting the remaining air bleed by slowly unscrewing until the air starts to escape, or by dry firing. To be honest, you have to ask yourself how often you want to remove your cylinder anyway, it being quickfill, and is probably not a huge issue to most users.

So I was ready to fit my new cylinder - or so I thought! Following the instructions I had to remove the silencer, and this presented my first problem as the fairing where the silencer joins the barrel was well and truly stuck on. It is supposed to screw off quite easily. After a lot of struggling this finally loosened, and off it came. Next stage is to remove the larger "o" ring on the barrel band of the gun as the A&M cylinder is just slightly larger in diameter.

Finally, the cylinder just slides down into place. There is a small "o" ring on the valve where the cylinder screws into the rifle and this may need replacing, and there is a spare supplied. I didn't do this is my gun is only a few months old, and so far there have been no leaks. And it's as simple as that. It takes minutes to fit, or would do if I had not had problems with the silencer! Not an A&M problem though obviously!


And so to filling - and my first problem with the cylinder itself. I use an FX stirrup pump. After removing the Weihrauch probe and fitting the new probe to the hose I found air was leaking badly to the point where nothing was getting into the cylinder. Puzzled, I tried the Weihrauch probe and found I was having the same problem, although I was able to get up to about 120 bar before air escaped and stopped me getting any further.

It was suggested on another forum that a hand pump wasn't suitable for filling the A&M cylinder as it needed constant pressure on the valve to fill properly. I emailed A&M, also asking if the use of a pump could be a problem. I was assured by Adrian that a pump should be fine and a replacement probe was sent which arrived the next day. Great service!

Next day however, having fitted the new probe I found I had the same problem. Puzzled I emailed them again, getting an almost immediate response asking me to send the cylinder back, and a replacement would be sent by return. I decided, however, that I would call in person as they are based only about 40 miles away, and they are open Saturdays and Sundays. I'm really glad I did, because not only was I able to see their setup, but I received a really warm and friendly welcome.

It was immediately apparent that Adrian wanted to make sure I was entirely satisfied, and he wanted to get to the bottom of why I was having problems, as he too was truly puzzled. Suffice to say, it was cured by placing a washer between the probe and the adapter on the hose! As easy as that, but as I hadn't had to use one with the Weihrauch probe it was something that never crossed my mind, and to be honest it hadn't crossed Adrian's mind either.

It's obviously something he hadn't come across before, but he's taken note for future reference. The upside to this though was that I was able to see just what a caring attitude they have to their customers, see for myself their setup, and for Adrian to show just how much effort they put into producing these cylinders. In fact, A&M are a true testimony to all the values we set on a cottage industry.

So, there we have it. There are already many positive reports on threads on various forums about these cylinders, and as mentioned previously Marksman has put some great vids up on Youtube - just do a search for A&M HW100 cylinders.

Visit their website to see what else they can offer http://www.amcustomgunsmiths.com, including for example a cylinder fitted to an AA S200 upping the hot count to 120, and other custom work and their own range of silencers.
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