I got a message late one evening from the guys at Skirmshop UK to ask if I’d like to test out the new Action Army VSR hop chamber. Less than 14hrs later it arrived, which is ideal when you need things to arrive on your days off work so you can plan your tech sessions. Then it was straight to the workbench. I must admit I’d missed the launch of this, and haven’t seen it in anyone’s rifles. It was more curiosity than excitement, all my guns have good hop setups in so it isn’t something I’ve been specifically looking for.

The AA hop unit was a genius piece of design all those years ago, and if you’re looking to upgrade from stock without doing and TDC drilling, it’s a great choice. There were however a couple of issues with it. The arm was a good fit, but not good enough and still needed shimming, whereas a cheaper option would have been one of the many CNC arms designed for the stock hop unit that arguably worked better on the whole. It wasn’t bad, it just wasn’t perfect. Worse though, by nature of the design, was the fact that to adjust the hop meant cocking the rifle, turning it upside down and fiddling around with an allen key to adjust. Now, I have a VSR specifically for testing things, and it’s forever changing setups. I get lots of stuff to play with, and I like experimenting anyway so the hop adjust when switching bb weights on the range or setting the gun back up after a parts change really slows everything down.

So, Action Army have fixed it. This is, I guess, the V2 of the AA. And I wished they’d called it that instead of “(damping type)”. I don’t know what it dampens.

Apologies for the poor lighting, I have to face the window for deliveries. Amazon, surplus, fast food etc. Straight out of the packet, the grey finish on it is absolutely beautiful, not that it matters. But it was worth appreciating. What AA have done is change the TDC type adjuster and gone back to a slider, the same as the stock hop unit. But with the rest of the design features (the good ones) taken from the old red original one. The BB stoppers are still there, the barrel spacer that holds the bucking securely in place it still there. But overall, it just feels much better engineered. After I finished stroking the lovely matt grey finish, I decided to get a beer down and install it.

The barrel spacer slides on first. New one on the left, old version on the right. The screwholes have been moved, so I have to swap the whole thing out.No idea why. The purpose of this is to butt right up to your bucking and improve airseal, and secure the unit to the barrel.

There are no instructions but there is a nice exploded diagram on the back of the box, note that there are a couple of washers and an o-ring to add to the slider first. I’m wondering how well this will actually work. The clicky sliders I hate, last VSR I was fixing that had one would shoot straight because the sweet spot was in between clicks meaning I couldn’t get it set as well as it should. What I like most about both the AA original unit, and TDC’s done properly like the Gunsmithy, are that you get an infinite range of adjustment. At a static 60m target, little deviations are going to make a difference at the other end, so it has to be bang on. Thankfully this V2 isn’t a clicker, so I’m happy. There’s no movement in the polymer arm that I can see, and the slider does apply even pressure across it, which is good.

In terms of nubs, there is a little rubber one supplied. Many moons ago, I bought some Skeees 3D printed nubs (very precisely made) specifically for the AA chamber, and because I run softer buckings (50-60 degree) I prefer to have a hard nub so that it doesn’t deform under pressure. It fits the oval-shaped hole on the V2 so it’s going in. The bucking of choice here is the Modify X-Range in 55 degree flavour, which is my weapon of choice and fits nicely into the Modify SSx 430mm steel barrel. Its a very snug fit, which is good but I had to hold the barrel spacer to stop the bucking pushing back and out of position.

One problem I did have (I think that’s three now…) with the original chamber was that once you’d attached the “TDC” screw bit that pulls the arm down, it’s already about 50% hop on, which may well be nub choice as well, but made it difficult to adjust for any bb under 0.45g. On this version, I have a bigger range of adjustment from off to fully on, which might help with some experiments I’ve got lined up.

Installing the unit, remove the slider arm thingy first, slide it into the barrel and then attach the arm in the hop window when it’s in. A bit of a pain at this stage, but all being well it won’t need to come out often and the trade-off is that the adjustment is miles easier once on the range. The slider is pretty tough to move, which is good because then it isn’t going to change position mid game (I hope). And it’s low profile enough that you’re not likely to catch it with anything very easily. Overall, I’m impressed at how much better everything fits together. The tolerances seem tighter, and the whole unit feels a better quality (not that the original was a tacky piece of kit). So far, so good. Yeah I like it, but getting it out in the field is very different to looking at it in the house (as some bloggers do).

So, I headed down to my local, Dirty Dog Airsoft, to do some testing inbetween a lot of toilet breaks. Straight to chrono, I’ve gained 20 fps on 0.20 which could be airseal as it’s a tighter fit on the bucking, or it could be because the gun got cleaned during installation. Still bang on the joules (0.02 under) for UK regulations and its still shooting nicely to around 90m. What does make a difference is being able to quickly adjust without that damn Allen key, so I’ve had a good session on different weight bb’s with quick adjustment. It holds absolutely fine, a bit stiff to move the slider but you’d want it to be anyway. The nub isn’t sitting as deep as the original, so I can adjust down weights as well, to 0.30 with hop off, so there’s better overall adjustment.

In terms of accuracy and grouping, it’s been a slightly windy day and the range on site does have a crosswind, and I don’t use a shooting rest so I can’t give any exact info other than to say that I can put crosshairs on a plate carrier sized target at 70m and hit it first time. Overall conclusion then – don’t buy the original AA, buy this, purely for the easier adjustment. If you’re running a tdc, I’d still get this because I like the machining of the unit itself. The bb stoppers are much better than the stock hop unit and I like the AA barrel spacers. Where a lot of people put emphasis on the fps side of the gun (trigger, piston, smooth bolt pull too) its the hop that you need to get sorted first, regardless of which platform you run.

The unit is available from Skirmshop UK for £52.95, many thanks to them for shipping one out so quickly to have a look at.