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:
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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
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the spread on the non-defective model tightened up by 200 pellets
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the variable scope may be slightly inaccurate at max zoom — backing off to half power results in lower spread (more testing needed to confirm)
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Behold — the final update!
Okay, so, don’t really remember what I wrote in the last few updates.
But in the past few days what I’ve done is take apart both the X20 & A30 and give them a clean and lube on the powerplant internals and pivot, and just a tad bit of grease on the safety pin notches because that was annoyingly catchy. I did also buy a cheap bore snake and use that on the A30 and lube the barrel with some silicone treadmill lube on the end of the bore snake.
The X20 had a broken top hat. Stoeger service/warranty support refuses to just send me a replacement top hat. They refuse to do anything without me shipping it to them, even though the part is clearly broken and I offered to have them null my warranty if they just send the part. I didn’t want to put the thing back together just to then pay to ship the entire thing to them to wait for a few weeks and then get it back plus the one part, so instead I printed a drop-in replacement top hat out of PETG-CF, put it back together with some moly paste (turns out you can get this for a decent price at the local fastener store, however the only data sheets I can find for it don’t say the MoS2 content although product pages from several suppliers do say 60-80% — this is Lloyd’s 62625 anti seize compound) following TinBumTuning’s general practices.
And, well, it’s fine now? Shot cycle twang is basically all eliminated, previously it was verrry twangy. Feels like it kicks less, too. And where previously it would take me dozens of pellets to get to a point where I thought it was sighted in, only to then have zero shift on me or just get a bunch of inconsistency, I managed to get both the fixed sights and scope sighted in only 21 pellets.
I then took two more five shot groups, which only had one shot that was maybe a random flyer. Every other pellet was either on rails to the crosshairs, or where I called it if I was moving too much while taking the shot.
It actually feels nice to shoot the X20 now.
Oh, and the X20 is now shooting Gamo Tomahawk Pointed pellets (all shots since rebuild some using those) straight, whereas previously it did not like any pointed pellets. And I haven’t even cleaned the X20 barrel yet.
The A30 is also shooting the Tomahawks straight now whereas previously it would only shoot consistently with flat heads, but I need to do a bit more testing to see how much of that is just reduced parallax error with the adjustable scope and how much is actually the rifle consistency.
I will note that the grease from the factory is terrible for actually using the rifle. On the A30, a bunch of it was dried up, but there was also excessive amounts in some areas. And on the X20, there was barely anything left, and I have lots of wear marks on the side of the piston. These are definitely not high quality products, but if you rebuild them after they’ve been sitting on the shelf for who knows how long in Crappy Tire, it seems like they are okay. Also the top hat is very undersized within the piston and spring, I’m going to print another one with a bit of preload to thicken the load bearing section, and decrease those clearances on both the piston and spring.
two five shot groups for each rifle, X20 on the left and A30 on the right. same 11 yards as always.
X20 shots are on rails, even makes me feel like a decent shooter. A30 has twang still, and I think some parallax issues with the adjustable scope and the user looking through it. It’s been tough to find the proper focal setting, but I’m starting to figure out the setback I need to use to avoid parallax issues (back up to juuust where scope shadow starts to show on the edges).
Still, THIS is the performance I expected out of a new purchase. Much better than before. I don’t think I included it in updates, but I did end up swapping scopes around to eliminate variables, and determined that yes the adjustable results in less consistent shots, but it didn’t account for all of it.
Now to sort out the crappy scope mount on the X20 (it puts the scope noticeably to the right of the center line, so zeroing over different distances will have significant lateral change), and probably print a new top hat for the A30 to guide that spring better, lighten the piston, and reduce the twang of metal on metal. Then to work on the triggers with the bushing mod, but that’s secondary, I’m already very pleased with the massive improvement on the X20.
another update after being away for a bit:
A30 is shooting okay now, possibly even well, with flat head pellets. It looooves flat head pellets. It is also very, very hold sensitive for the power (in my inexperienced opinion).
however, my X20 broke today — the spring guide top hat thingy on the piston side just sheared in half where the two diameters meet. I think this is indicative of the quality of the products.
because I’m stuck on this, I went and purchased an HW30… which I guess I should have just done in the first place, as I’ve now spent an equal amount on shittier rifles. once it arrives, I will probably take the A30 apart too and give it a full clean up, as judging from the internals on the X20, it needs it
If you come to a solution, and remember me, can you ping me with any success you find? I’ve got a single-shot Gamo and my hits are all over the place like yours. I’ll dial it in, pick it up a month later, all over the place again. And this is with multiple scopes over the years!
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.
idk how to ping people on here, but I just posted an update in a top level comment
not the final update, but something
TL;DR:
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first A30 was probably defective from being dropped hard enough to break the butt pad mount post
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second A30 is more accurate
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there is a non-zero amount of user error in managing the recoil, as proven by testing one of the new rifles in a custom artillery hold mount (rifle stock clamped on a linear bearing, essentially), which led to more accurate grouping than my previous attempts
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I still think there’s some amount of parallax error going on, because the scope distance markings are so far out (15 yards mark appears most accurate focus for 11 yard actual distance), but I haven’t tested it well enough yet to verify
what’s kind of weird lately is of my last dozen rounds of shots or so, more often than not the first shot is the most accurate, only to be followed up with a shot an inch away lol. and only with the new rifles, not the old one
re: idk how to ping people on here
You can mention them by user name in the post, like @mrgoosmoos@lemmy.ca and they’ll get a notification similar to if you replied directly to one of their posts.
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