I bought a Stoeger A30 .177 495fps from Canadian Tire because it seemed decent for the price and had a 3-9x40 scope. I’ve run about 150 pellets through it now, and I’m just confused by the spread.

I know that everybody says there’s a break in period during which it will be inconsistent, but I get the feeling that what I am seeing is worse than expected. Further, consistency doesn’t seem to be improving. The image shows four groupings:

  • target 23, 10, 1 (in order of firing, first two last night and 1 this morning): Stoeger
  • target 30: Marksman

These are ~1.5" squares, and I’m aiming for the center of each target. I am not a great shooter, I wouldn’t even say good - I just want to get rid of a rat in my backyard, and I haven’t shot in years. But I used my 20yo Marksman 1745 with a floppy barrel and a 4x20 scope I can barely see through, and I can get more accurate and better groupings.

These shots were taken at 11 yards. I’m using a camera tripod with a custom block on top to support the barrel of the Stoeger and the stock of the Marksman (as laying the barrel on it results in deflecting the barrel up about 8 MOA lol), and using a loose hold at the butt of the rifle. I’m a fidgety fucker that can’t stay still, but I’d say that I’m still enough at release with the Stoeger, considering the trigger is far smoother and lighter than the Marksman and I’m holding it farther from the supporting pivot point (both farther down the rifle and a longer rifle overall).

Another thing to note is that the scope that came with the Stoeger could not be mounted to it without shimming the rear mount up, as I immediately ran out of elevation adjustment. I used a couple layers of electrical tape, didn’t over tighten it, and have retightened it twice since as it settles in. It’s possible, but I don’t think that the scope is moving shot to shot.

It’s weird. I’ll have two of three shots that are somewhat consistent (down and to the right, for example), and then the next shot will be twice as far the opposite way, and the following shot up and the right. It just seems like too great of a spread for only 11 yards, even this early in the break in period. The box was semi-open when I bought it, but the rifle itself seemed untouched, so I also have some concern that somebody returned it and the rifle itself has an issue. Although I don’t know what that would be, because it looks mint, and oh boy is the pivot joint for the barrel ever tighter than the Marksman. I can move the Marksman barrel in all directions when closed, but the Stoeger is solid. Better be, considering it’s like twice the weight for the same claimed fps

final edit (I think) because it’s going to be too cold to continue soon:

  • this trigger is not a 'pull gently until it goes off" despite being a two stage smooth trigger — grip-and-pull alone decreases the spread by half for me

  • the spread on the non-defective model tightened up by 200 pellets

  • the variable scope may be slightly inaccurate at max zoom — backing off to half power results in lower spread (more testing needed to confirm)

  • mrgoosmoos
    OPEnglish
    1·
    3 months ago

    Is your air rifle a detuned version?

    I bought a chronometer and did some testing and oh boy does the way they detuned this thing ever suck for consistency.

    In stock form I am getting an average 11% deviation from the mean fps (across 10 shot groups from 10 different pellets). Yes, I sat there and fired 100 shots across the chronometer. then made a change to the rifle and did it again.

    It was incredibly validating to confirm my suspicions, that it fires inconsistently. Every now and then I would feel a shot that just had very different recoil, usually a shot that didn’t go at all where I expected it to. And now I have that in the data as an outlier in the muzzle velocity. And the shots overall didn’t feel perfectly consistent, but the minor variations were hard to pick up on. Only one of the ten pellets had a spread of <5% the average in stock detuned form!

    Keep in mind that these are all pellets that I can shoot from an HW30 and they go where I expect them to. The same pellets across the chronometer have 60% lower deviation from the mean velocity in the HW30.

    By plugging the bleed hole in the piston, power went to excessive levels but consistency in muzzle velocity improved greatly - down to an average 3.1% deviation from the mean muzzle velocity for each pellet group. And that’s not just from the fps increase - the actual fps scalar deviation dropped on average to 55% of the previous value, despite exit velocities being on average 1.8 times greater. Literally near twice the velocity and half the inconsistency. The rifle is simply not designed well for the detuned version.

    I haven’t done any actual accuracy testing yet, but I have to imagine a more consistent exit velocity will help accuracy. I just need to tune it within legal levels before it leaves my basement.