QB18 Anyone? [Archive] - AirgunOne.com

vinceb

12-29-2008, 07:32 AM

If you're looking for a project, then you've found a good 'un. If my Hammerli 490 (rebadged QB18) is any indication, it's a likeable gun once it's gone through. But it certainly needs 'gone through'.

This is a review I wrote of it (but haven't posted anywhere yet):

Hammerli 490 Express - What's in a name?

Marketing being what it is, I guess it's unavoidable that the names of the historically great craftsmen eventually get dragged into the deep, dark well of mass distribution. The old-timer made a good product, but he didn't do much for volume sales. In the 1860's Johann Ulrich Hammerli started a company that has eventually earned a reputation for a series of high quality precision rifles and pistols (both air and cartridge) that their founder would probably be very proud of to this very day.

But the 490 Express ain't one of them.

I'm getting ahead of myself... let's start from the beginning - the 'Hammerli 490 Express' is a Shanghai product, a rebadged QB18 of which the Compasseco TF49 is another variant. The gun is part of the lineup which is supposed to redefine Shanghai, and bring them up a notch or two from where they previously resided with their B1/B2/Model 61, B3, and B4's. The AR1000 is the flagship of this effort, and that copy of the Norica Marvic rifle has done a fair job in this capacity. And the QB18/Hammerli 490? Well... unlike the AR1000 it isn't an entirely new product for the company. It borrows heavily from the old B1/B2 breakbarrels, but it's also a bit more than a simple rehash of those guns. Which isn't necessarily such a liability - oftentimes an airgun has a poor reputation more from quality control during manufacturing than from actual design deficiencies. The 490 illustrates well what I mean.

My interest in the 490 waxed when Tom Gaylord did a very complimentary review of this gun in Jan '08, and it waned when someone on the GTA forum tried out the generic QB18 variant and had serious problems. Still, I was getting more interested in moderate powered guns so I eventually decided to give it a chance. I was almost permanently spooked by it's aforementioned similarity to the old B2 rifle, but curiousity finally won out and I ordered one. This particular example I was purchased as a 'refurb' directly from UmarexUSA, and it cost me all of $57 shipped. Since the retail for this gun runs from $75 to $90 - before shipping - I'm pretty OK with that, and I'll put up with the 'R's they stamp into the stock and the action.

Upon first inspection this rifle gave every indication of being a very low-mileage gun, possibly a display model... very good cosmetically, and the factory rust-preventative had not yet been removed. The metal finish was a bit rough, not as bad as the old B-series guns that I had in the past but not up to Crosman Quest standards. The stock was stained a dark, muddy reddish-brown that is tolerable, and far better than the orange paint they use on the real cheap guns. Knowing that this is a sorta youth gun the general heft and balance felt pretty good, light (6lbs 2oz) without being too light, and a shortish pull length (13.5") without being too short. Certainly OK for me, and probably a good gun for a mid-to-older teen. But it's not a kid's gun in the same vein as the Gamo Delta or the Recon, that is built for someone of less-than-adult stature. One nice feature of this rifle - it's got decent sights. They aren't fiberoptic, but they are solidly built with good detents in both directions. The hooded front blade is sized about right for the rear notch.

As I was hefting it my finger started reaching for the trigger - and whoa! I hadn't made sure this thing was uncocked and unloaded! So I break open the barrel (lockup is stiff) and start pulling it back. The barrel gave only a modest amount of resistance - and before I knew it I had actually cocked the action. So that's the main reason it's billed as a 'youth gun' - out of the box I'm fairly certain my 9 year old girl could have cocked it (although she not be able to shoulder it)

So I go ahead and run some pellets through it, and lay a few across the chrony. Gamo Match aren't getting out of the 400's, but that's not such a big deal since this is an indoor or short range plinker. But what IS a big deal is the loose-as-a-goose barrel pivot. It didn't just have some play side-to-side, it had SERIOUS WIGGLE ROOM. So before I start seriously shooting the gun I decide to look at the barrel pivot.

It's a simple arrangement with a standard pivot bolt held in place with a small locking bolt on the side (the same arrangement as the B1/B2 guns). Unfortunately the bolt only has 4 cutouts, which means that the bolt can only be locked down in 90 degree increments, which is a fairly coarse adjustment. Very often the right tension on the bolt is somewhere between locking positions; going one way makes it too loose and going the other way too tight. So with this design Shanghai is already saying that the gun doesn't have to be RIGHT, it just has to be 'close enough for government work' (which is very near the truth). It needs at least 8 cutouts in that bolt head if we're gonna have any confidence that the pivot can be adjusted properly - and even that's marginal.

I pulled the pivot apart and found no thrust washers, only the roughly machined breech block bearing against the roughly machined yoke arms. I moly it up and put it back together. And that's when I found out WHY there was so much play - the yoke arms were so far apart that I couldn't tighten the bolt enough by hand to firmly squeeze the breech. I was able to get it a bit closer, but not nearly where it should be. While I was fooling with it I also drizzled a bit of 'moly syrup' into the cocking slot, as the seal was honking while being cocked.

I took it to my 10 yard range, and started pumping Gamo Match and Chinese Domed (NOT INDUSTRY BRAND!) pellets through it, and found that (with open sights) it was doing fairly well. 3/8" groups were pretty easy, which surprised me. The trigger was a bit grody but not too bad, a little creep but nothing intolerable and the firing cycle was passable. The auto safety is a bit of a pain... while it looks like it oughta be no worse to operate than a B20/B26, it is. The button really has to be pushed ALL THE WAY in, and the proximity of the stock makes that a bit tough. All in all, though, I decide that the gun is probably worth a bit more work.

Back inside I started pulling the powerplant apart. The safety mechanism is partly held in place with a thin roll pin that stretches across the tube's diameter at the very rear. Or at least it's supposed to. On this one the holes were not opposite each other, so the assembler had to bend the pin as he fed it through. That pin also retains two small springs, one of them was caught in the pin (instead of under it) and a coil had broken off.

Not encouraging.

After getting the safety mechanism and removing the barrel I was able to pull the piston out. The gun uses what looks to be an AR1000 (Norica design) seal, and since it was slightly damaged I replaced it with a good used one from a TF89. Oddly enough the seal fit perfectly, despite the 490 having a 25mm tube vs. the AR1000's 26mm. Now we know why the AR1000's tend to have loose seals - it appears that Shanghai uses one part for each, and if they make it a nice snug fit the the AR1000 it'll be too tight in the QB18.

The piston is made from a rolled sheet-metal tube and the seam isn't welded. That's not such a bad thing - except for the fact that the seam (both sides of which didn't really match up that well) is on the top, which is the part that bears against the inside of the spring tube during cocking. The piston should be as smooth as possible here so as not to gouge the tube, so I had to clean it up with a file. And the piston isn't hardened which made this job easier - but it also makes for a faster-wearing piston.

The trigger is the direct-sear straight out of the B1/B2 (except for the plastic blade), and the same 5mm pin that would bend from stress on the B2 models is also as the spring anchor and the trigger pivot. I didn't dress the trigger surfaces because this one wasn't too bad (about 3.5lbs), but I did moly it because I DON'T want the surfaces to wear (like the did on my 'auto-fire' B2).

The actual compression tube bore didn't look too good - I could see rust and a rough-ish finish, but at least there were no visible gouges. A few minutes with a 400 grit stone followed by a 600 grit flapper improved things rather dramatically. I also took the time to drill a new hole for that rear roll pin so that I could install it straight. After the usual deburring - well, maybe more than the usual deburring - and the usual cleanup I reassembled the gun using a medium-bodied grease on the spring. No tar here - with a modest powerplant like this one I didn't see either the necessity or the desirability of gumming it up with something so heavy.

When I reassembled the breech pivot I pinched the front of the yoke arms in a padded vise so that I could easily tighten the screw to the point where the breech block is actually snug. Predictably the best tension was achieved between locking points, but I torqued the bolt down to the tighter position. I figured that since the mating surfaces between the breech and the yoke were so rough that they'd wear in fairly quickly (even with moly) and mitigate some of the initial excessive friction. Turns out I was right about that. The breech seal also needed a bit of shimming, but nothing extraordinary.

Got it all together and after a few break-in shots it's doing midweight pellets (Premiers, Hunters, Match) in the mid-500's, which is well over the advertised velocity and a level of power I'm pretty happy with. Accuracy is about the same as before, which is to say quite acceptable, and the 16-lb cocking effort, 3 1/2lb trigger, and mild firing cycle mean that this gun isn't tiresome to shoot. The very stiff breech has already worn in to being moderately stiff.

So my final verdict? I like it. In fact, I like it very much. The weakness inherited from the B2 series (the trigger, soft and poorly made piston, the single pin holding everything together) probably won't amount to a hill o' beans on this rifle... the mainspring is so light that the direct sear trigger friction ain't too bad and I can't foresee accelerated wear being a problem. I expect it to last a long time, and I expect it to shoot well while it lasts. And I like the weight, the feel, and the balance of the gun.

So why did I seem so down on this thing at the beginning of this write-up?

For two reasons. First, as is amply illustrated by my tour through the poorly machined innards of this thing, putting the Hammerli name on it is in a sense both misleading and almost a slander against Johann. It betrays a complete lack of respect for his name and his legacy, and just because that practice is common don't make it right. Sold as an Industry Brand gun? I don't have a lick o' trouble with that. But not as a Hammerli. And my objection has nothing to do with the simplicity of the gun's design or even its country of origin. Tighter QC on the machining and fitting of parts would completely remove this objection - the old Slavia's (the 618, 619, and 620) show how a dirt-simple gun can still be very well made. Granted, the good accuracy indicates a nicely finished barrel bore (which is extremely important, since it's one of the few things that an owner probably can't fix), but that's about it. I'll go a step further and say that the cosmetics aren't even a major issue.

Second, that retail price of $75-$90. Many object to the proliferation of plastic on the Gamo Delta and the like, but those guns are built like a Swiss Watch compared to the 490. The QB18 can be found for about $50-$60, and $60 is about what I think the tolerable upper price limit is on this rifle. If you get one there's a fair chance that it's going to bit of a project (not unlike the ubiquitous B3), but at least no exotic techniques, materials, or equipment would likely be necessary.

So that pretty much sums up my take on this gun. Hopefully they're not all as rough as this one, but I'm not holding my breath. But once it's made right it is, in my opinion, a very likeable gun. And out of the box, with a little more care from the factory it could live up to its billing (or at least get a lot closer). But unfortunately it just ain't there.