the holster will also fit HW 40-45-75 6004 and it is open ended so an ultra would fit will not snap over the top out of the package but i believe there is some adjustment in the strap if needed amount unknown
if you are talking about a reflex sight or another add on top or bottom, you would be out of luck the gun fits very well but that is all any sort of sight would need a speed draw style holster and the chances of finding one would be very hard to impossible https://polenartactical.com/shop/home/1310-desert-eagle-optics-cut-holster-bgs.html
now that holster is not cheap and is molded making the fit unknown
I appreciate the help. Wouldn't even know what to call it, since never use holsters. But that is exactly what I was imagining would be needed.
Another idea I was trying to think if possible for a gun is the pager belt holster, like Encased Belt Case for Samsung Galaxy S23 Ultra with Holster Clip [Military Grade] 10Ft Shockproof Protection - Rebel Series (S23 Ultra 6.8-inch) https://a.co/d/b80guDp
That could have red Dot installed and not have the issue fitting in enclosed pocket like normal holster and draw straight horizontal instead of vertical. I may have to waste some kydex playing out 3d attempts.
holsters for air guns is at best a hit and miss situation, you buy and try and have failure or success and the main reason is that few of us use holsters now seeing that the HP-01 is not a copy of anything it just gets harder but then you add and scope or dot on the pistol you have made it near impossible and now you get into expensive holsters to try and hope you didn't waste 150.00 bucks now the most common scoped holster would be for a Thompson Center Contender or Encore but the barrel length are commonly to be 10-16 inches and many are designed to be warn across the chest which would work in and outdoor hiking setting https://www.pistolpackaging.com/Bandito_Scoped_Holster_Thompson_Contender_p/bsh-tcc.htm now would the Alecto fit, more than likely and the extra holster could be shortened by a leather craftsman i would guess
it is a crap shoot i am afraid but money can solve all problem but will it be money well spent
Thank you again Mike. My Google searches were not working since I didn't know what terms apply. The second picture for the Thompson, covering the whole scope, would be cool for protection. But for the little pistol holosun, it would leave too much open empty space inside the pocket. I don't have a vacuum table, but I guess I will attempt my first custom gun holster
That's kinda what I was thinking. Too tight at the front, a lot extra room at the back. The speed draw so far seems the nicest choice, if I can make it fit