If I'm not mistaken, almost all modern compound bows are available with 50lb limbs and 80-90% letoff. I believe there are some out there available with 45lb limbs, but any 50lb bow should be adjustable down to 45. Most should be adjustable for draw weight with nothing more than a hex bit or allen wrench.A friend and I both bought used, cheap, old compound bows just for backyard practice at 30 yards or less.
Mine was set to 45 lbs by a prior owner. It goes up to 55, I'm told.
His was set at 80 lbs at the shop where the first owner got it, and although it's been turned down somewhat by loosening the limb bolts, it's STILL in the mid or high 70's, I think. We took it to an archery shop but the owner said a bow that old (30 years) wasn't safe to use, or put in his bow press. So we didn't get it tuned up or tested for exact draw weight.
My friend and I "can" shoot this bow that has 70-something peak draw weight and a 50% let off, but we don't like it.
It's more work than it needs to be. The arrows bury themselves too deep into the target block to get them out easily without bending the shafts. And if the arrows miss the block and hit the ground, or a tree branch, they almost always bend or break.
We both think that 45 lbs is good weight for fun shooting within 30 yards or so.
NOW, HERE'S A QUESTION: How many compound bows are adjustable down to 45 lbs? Is that too low for most designs from most manufacturers?
And, can they be adjusted by the user, who doesn't have specialized training or tools, like a bow press?
As mentioned above by someone else, both Diamond and Mission made a bow several years ago "targeted" at younger shooters that is fully adjustable from 5-70lbs with easily adjustable draw length as well. The "idea" behind it was a bow that a young shooter could grow with and not have to keep replacing as they get bigger and stronger. They were relatively cheap as well as they were only around $300-400 brand new. My nephew had one when they first came out and he really liked it.
Now, to address what you said about bending and breaking arrows. I have to assume you are shooting aluminum arrows? I have never bent a carbon fiber one and only managed to break carbon fiber ones by hitting them with other arrows. I would highly recommend switching to carbon fiber with any remotely modern compound bow. If you feel like you have to have aluminum for whatever reason, Easton makes a hybrid one that has a carbon fiber core.