In .177cal today with open sights, what a blast. I had to crank the elevation all the way up, thought I broke it.
Once we figured out where to hold we started getting a few hits with lots of near misses. It seemed like 2 full seconds to get there. I wonder how fast they were going upon impact (chronos 850 at 5 feet) I dug a few out of the dirt and they were pretty deformed.
It sure made shooting them at 50 yards a lot easier, anyway we had fun.

What pellet were you using?  If I knew that I could estimate the terminal velocity.  If, for example, you were using JSB Exact Heavies (10.3 gn) the velocity at 105 yards with a muzzle velocity of 850 ft/s would be about 570.  This is about what a 10 meter air rifle does and flattens pellets when striking steel backers.

Yes Sir, they were Crosman Premier 7.4 grain pointed.

I couldn't find data for that exact pellet, but given similar weight and shaped pellets, the terminal velocity would be around 300 ft/s.

You would probably do a lot better with Crosman Premier lights (7.9 domed).  The initial velocity would be a little slower, but these will not slow down nearly as quickly.  Also, domed pellets are less likely to develop spiraling than pointed.  Another thing, that seems a bit unintuitive is that domed pellets usually have a better ballistic coefficient than pointed ones as well.

Shot some more the other day, I think I need to use heavier pellets, any suggestions?
Also, the open sights are pretty good but I sure think it would be more fun with a scope. I've read a bunch about it and opinions are all over. I'd like a no nonsense mount, preferably one piece and a decent scope. By decent, variable not over $150 if that's possible. Suggestions appreciated.

Your choice of good pellets are:  Crosman Premier 7.9 and 10.5 grain, and JSB Exact in 8.4 and 10.34 grain. You might also try the H&N Field Target Trophies, and the RWS Superdome.  

For a scope, one of the best values for an inexpensive scope is the Centerpoint 4-16 x 42.  It has a variable objective that will focus from 5 yards to infinity. Some individual samples may exhibit some mechanical sloppiness on the ocular focus ring but can be fixed with tape or o-rings. (I have one that is sloppy and another that is sound.)

For one piece mounts, BKL is one of the better ones and can be had in a droop mount.  This is a good feature for many spring air rifles, especially with long range shooting.  100 yards is long range for a .177 air rifle.

My Benjamin came with a a Center Point 3-9 X 32 and I am quite please with it, good feel to the power adjustment ring and it feels solidly built, I am quite surprised with it, I would not put it on a high power rifle, but for this .22 airgun, it does very well.

I've been looking at scope mount options and reading about it. Most suggest a riser then rings or a one piece combo mount. They all appear to me to put the scope too high or higher than I think it should be. Is there a reason rings couldn't be put on top of the rail already on the rifle? I am considering a Hawk 2x7x32, what rings would that need and still not be too high? BTW the rifle was made in 2000.

I used RWS mount with my Hawk 3-9x56 panorama on a RWS 460.

http://www.pyramydair.com/s/a/RWS_Lock_Down_1_Pc_Mount_w_1_Rings_11mm_Dovetail_Barrel_Droop_Compensation/2406

I use these in all my .177 rifles, they are one hole wonders...

https://www.amazon.com/Crosman-Premier-Domed-Caliber-Pellet/dp/B000FEUUF6/ref=sr_1_7?s=sporting-goods&ie=UTF8&qid=1489172351&sr=1-7&keywords=crossman 177 pellets&tag=vglnk-c102-20

Cross man 10.5 grain domed in my RWS 34 .177 shoot great. I just mounted this scope yesterday.

http://shop.opticsplanet.com/nikon-prostaff-target-efr-3-9x40-rifle-scope.html?_iv_code=NI-RS-6734&utm_source=google&utm_medium=cpc&utm_campaign=plusbox-beta&gclid=CIH30ryImtMCFce2wAodgC0Exg

Well, I did get some Crosman 10.5 domes and they do shoot good. I haven't tried the 100 yards again yet.
Scopes, here the thing , ordered a scope and Droop Mount in case it needed it. It needed it, but the droop mount places the scope too high now. Why not redesign the barrel nut so it doesn't need it? Cheek weld is crap because scopes too high. And why don't most air rifles come with weaver rails instead of the 11mm BS.
Its like there's several design flaws that will be that way forever and if you asked why they'd say, because that's the way its always been.