Gun choice dilema!

I own both the s510 and regal xl. Can’t go wrong with either one. Accuracy, no difference. 510 has a little more velocity. Both look great and workmanship is exceptional. Regal is shorter unless you get carbine version of 510. Regal is a little louder with factory moderator, 510 has shrouded barrel and side lever cocking. Both have a decent shot count of around 40 per fill. If I had to pick between the two, it would be a very difficult decision. You will be happy with either.
 
Biagio26,

I can only say that I wish it were I who had to make the difficult decision between those three rifles. For long sessions of target shooting, some might give a very slight edge to the side-lever cockers. I have a Daystate Huntsman Classic (24 FPE version), which is easier to cock than the Regal. Yet, I'd love to have a Regal despite the higher cocking effort.

Do you have a three-sided coin?
 
The Air Arms is a very good and well finished piece of equipment as it comes but can be made better with the addition of a regulator and can be even better yet with some tuning!
That said I have a 500 and a 510, and even adding the cost of the regulator to the price of the rifle it would be very hard to find a rifle of that quality or accuracy in it's price range.
They work very well out of the box but really shine with a good regulator and tune. If you are looking for shot count buy the long rifle not the carbine as it has a shorter air cylinder thus fewer shots per fill. I think if A/A would put regulators in there rifles from the factory they would sell way more even with the price increase to cover the cost of the regulators as the quality is second to no one! Just my findings for what it's worth. I think you will be happy with what ever you end up buying as they are all very good air guns!! J.L.
 
The HW100 magazine is supposed to be particular easy to load and reliable with 14 shots where the other two are 10. If you pump, Regal XL has a higher fill pressure of 230 bar compared to 200 bar for the the other two. At least in Europe you have 4 versions of the HW100 with sporter or thumbhole stock in standard and carbine size (as well as FSB versions but they are louder than the ones with the moderator). It looks like AOA has flashy laminate stocks too.

@airgunmonkey any idea when did Weihrauch fix the barrel issue? They make too good of a product to not address that.

@cahil_2 any idea why https://www.pyramydair.com/s/m/Air_Arms_S510_XTRA_Ultimate_Sporter_FAC_Air_Rifle/3372 says 20 shots per fill? I have in my notes that the s510 is not pellet fuzzy. Have you noticed a different with the Regal XL?
 
I've read good things about all 3 but have only owned the Daystate Huntsman (Regal). It was a very fine handling and shooting gun. If you purchase a used one and decide you don't like it you can almost always get what you paid for it in return as they're very sought after. 

Accuracy wise I've heard all 3 are superb. Of note, I had a Neil Clague moderator on my .22 Huntsman and it was fairly quiet. I have read that the (Regal) factory moderator is not effective if noise is a concern.

Here's another consideration:
HW100 8.2 lbs & 38.4" (with moderator)
AA S510 7.55 lbs & 43.75 (without moderator) + power wheel / adjustment
Regal 6.17 lbs & 40" (with moderator)

Here's a picture of my old Huntsman with a Sightron SII Big Sky 4-16x42 AO:

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