Hammerli 490 - Part 2
Another great youth rifle
by B.B. Pelletier
Today, I'll clean the barrel of the Hammerli 490 Express and shoot the rifle for velocity. First, cleaning the barrel. For those who have joined us recently...I try to clean the barrels of as many new airguns as I can. I can't clean some of them, such as certain underlevers, sidelevers or repeating PCPs, so I just shoot them. After 500 shots, their barrels will be about as clean as if they had been cleaned the way I'm about to describe.
Cleaning the barrel
I only clean steel barrels, because brass barrels are too soft to clean this way. Use a new brass bore brush of the appropriate caliber (.177, in this case) and load it with J-B Non-Embedding Bore Cleaning Compound. Then, from the breech end, push the brush all the way through the barrel and out the muzzle; then, pull it back and out the breech. Do this 20 times, and you'll remove all the burrs, rust and dirt left over from manufacturing. Even though a barrel looks bright and shiny, it probably still has rust left from the bluing salts and some rough marks from rifling.
This one was average - very dirty and lots of rust. By pass No. 10, the brush was moving easily in both directions. But, the looseness of the barrel joint was bothering me, so I removed the action from the stock and tried to tighten it. It uses a grub screw on the periphery of the main pivot bolt. The main bolt head has four cutouts into which the grub screwhead fits. The object is to tighten the main bolt, then lock it in place with the grub screw interlocking with one of the cutouts...except that was impossible. When the bolt was tight enough, the cutout didn't align. When it was aligned, the barrel was too loose. So, I gave up that idea and just lubricated the gun.
Because of the rifle's low-rated velocity (495 f.p.s.) I oiled the mainspring as long as the stock was off. It appeared dry, so I dropped 7-8 drops of Rem Oil (a gun oil made by Remington) on it. Having done that, I also put 3 drops of Crosman Pellgunoil down the transfer port. I don't know if the piston seal is synthetic or leather, but at this low velocity, it really doesn't matter. Petroleum oil is fine, in this case. I could have used the Rem Oil, as well.
Velocity testing was revealing!
The rifle appeared to "wake up" in stages as I shot through the chronograph. Ill show you the first spring shot with 7.0-grain RWS Hobbys, and you'll see what I mean.
That performance suggests there might be a leather seal in this rifle, because it seems to be gaining pliability and greater sealing capacity as it goes. My observations didn't end there. Crosman 7.9-grain Premiers were next.
Crosman 7.9-grain Premiers
The breech fit for Crosman 7.9-grain Premiers was very tight, so I expected this pellet to wake up the piston seal some more. It didn't disappoint me. The first shot was at 536 f.p.s. - exactly where the lighter Hobbys were shooting. That suggests that the greater resistance of this heavier pellet further improved the sealing of the piston seal. The low was a shot at 533 and the high went 553 f.p.s. - the same as the Hobbys! That's remarkable.
Air Arms diabolos
Next, I tried the heavier Air Arms Diabolo Field pellets that are made by JSB I have the ones with the 4.52mm heads. Surprisingly, velocity didn't seem to go down by that much, even though this pellet is another half-grain heavier than the Premier. It's an 8.4-grain pure lead pellet that fits the breech very easy, so there might have been reduced friction at work. The low shot went 523 f.p.s. while the fastest went 540.
Send in the clowns!
Okay, now it's time for the trick pellets. What'll she do on Raptors? Nothing! That's right, the gun wouldn't shoot Raptors out of the barrel! One did escape at 283 f.p.s., but that was it. Crosman Silver Eagle hollowpoints went from a low of 522 f.p.s. to a high of 652, with no indication of detonations. Clearly the Hammerli 490 Express is not a rifle that likes trick lightweight pellets.
More than appearances
Just as clearly, the 490 Express is capable of speeds greater than 495 f.p.s. The last QB-18 I tested was even faster, but it also required another 5 lbs. of effort to cock. Remember, this rifle cocks with just 13 lbs. effort. I'm looking for youth rifles, so I'll take the lighter cocking.
Who's your daddy?
Okay, as I write this I have already shot the 490 for accuracy (with open sights, only). If you have an extra $90 jingling around in your pocket, get one. We'll talk more about it later this week, but just trust me this time.