Carl, that sounds like you have a great load there. It may be a little too much of a good thing for silhouettes, though.
In regard to target damage, I think you will be ok. If your range has T-1 steel targets you should not have any trouble. If you have some old soft steel, you MAY punch a hole through the chickens.
In regard to knocking the rams down, that load should do it with no problem. The "rule of thumb" is that you need about 1.00 Lb-ft/sec of momentum to reliably knock over the rams, no matter what the range is. According to my Sierra ballistic program your load should have about 1.17 Lb-ft/sec of momentum at 220 yards. The rams are either 200 yards or 200 meters on most handgun ranges, depending on where you shoot.
I used to shoot a 14 inch Contender chambered in 7-30 Waters and had good luck with it.
I kept it tamed down with starting loads from the Sierra manual. I was shooting 150 grain Matchkings just over 2000 fps and never lost a ram with that load. I did boost the load up somewhat when shooting in specialty matches where we shot at 500 meters.
If you are worried about the target damage use a heavier bullet and therefore slow the thing down a little. Or just slow those 125 BTs down a little, you do not need 2600 for silhouettes.
At any rate, take that thing silhouette shooting and have some fun.
