Well Tim, I'm not sure what a sliding sledge is......
but I met a man at a dig once that had a 2 1/2 - 3 foot long
and an inch or a little more in diameter iron bar with a chisel
on one end and a sliding weight enclosed in an area that
took up about the top 12 inches of the bar. You set the
chisel end where you wanted it and then just slid the weight
up and down to drive it in. It was beautifully made and the
perfect tool for working in tight quarters. I really wanted one.
Turns out the man made all his digging tools himself. I asked
how much he would charge to make one and he said it was
more a labor of love for him. Apparently he would search
out and use just the right iron/steel for the job. Materials
and labor he said it would be $150.00- $225.00, but he
wasn't that interested in getting into it.
The man lives in Kentucky and said the tool was perfect
for extracting Fluorite specimens from their limestone host.

Not sure if that's what you are referring to, but that's my
story and I'm sticking to it. 

2011 Earthquake and Hurricane survivor,
Joe

Thanks Joe, we just had lots of rain in Alexandria, and just twigs and sticks blown down at the Chester house. Many others did much worse in Richmond and Petersburg areas. We let one family stay in the Chester house until they got power back -- about a week.
    You are right about the sliding sledge. I'm going to check farm supPliers, because I once saw one for driving fence posts.
     The fellow's home made rig reminds me of the advice in John Sinkasas book: buy a "spud bar" then have a custom metal shop make a slight bend at the pointy end. Extra points for a shop that can insert a hardened carbide tip.  That was his favored pocket opener.  Heavy enough to "throw" and just enough angled tip to pry.
    Of course Sinkakas lived when there was more industrial shops in America, but I suspect they can still be found.
     Hardware stores in Amish country might be a good place to look next time I'm in Ohio.

The DC area fared worse from this week's tropical storm rains and flooding. I may have to check the creek next to the community center where the Northern VA Mineral Society meets.  It cuts through ancient river gravel/cobbles, with some jasper, smokey and wood to be found here and there.  I collected on the creek a few days after the last summer meeting (and first meeting we attended after joining), so now I can bring show-n-tell and suggest an arduous field trip at the September meeting!