I suggest you chrono a full string from 190 bar to 90 bar with and without the pot then you will see how it functions. It's possible if you chrono just a few shots (say 10) you will see more consistency but that will be coincidental depending on the cylinder pressure. Removing the pot shifts the pea...

S400 with Rowan mag would be (and was) my choice too. If you want to up the budget, an Ultimate Sporter and single shot loader for HFT.

You will notice that as you close the bolt on the .177 the pellet is pushed up into the breech, rowan engineering get round this by making a small piece of curved metal that fits in the tray, this helps to keep the pellet level as it accesses the breech, it's all to do with the fact that all the bo...

Random shot distribution is unlikely to be power but I'd still check with a chrono (preferably with moderator removed) to confirm power is consistent. Are you sure your scope is okay and is mounted securely, and your barrel is secure? After removing and refitting the cylinder I take care to ensure t...

I don’t see how the below setup can have a first stage.... I see what you mean! I'd wind the second stage right out and the first stage in, then re-assemble and set the first stage travel (firing on first stage only) then bring in the second stage. We can't assess from this photo what the trigger w...

Having seen photos of Richies trigger it seems strange to have one set screw way out and the other hidden in the trigger and it could be firing on second stage with no first stage. So Im not convinced the procedure has been done by the book yet. Seems strange the weight setting is spring bound but ...

I don't mean to cause offence but are you sure you actually have a second stage? The symptoms suggest it may be firing on the first stage. Even with the adjustment spring binding you won't get much weight on the first stage. You should feel a distinct increase in resistance as the second stage screw...

Even though grouping changes you can't always be sure the pellets are clipping. A moderator will change the harmonics of the barrel so the preferred pellet can change. If the groups are just opening up randomly I'd be looking for other causes. You might try shooting into a bucket of water and retrie...

You don't say how big the POI shift is but, more important, are the groups okay? Bear in mind the Q-tec has asymmetric baffle holes so the excess air will not act evenly on the pellet.

If you don't want to fit a fixed picatinny/weaver rail on the S510 and S400 you can get inserts to fit in the mount clamps. These don't raise the height of the sight as would be the case using a picatinny-to-dovetail riser. I've used them for other types of sight, not ATN, but I don't see any reason...