The fixture pictured took maybe 20 minutes to make, including drilling and tapping. It's as effective as any prettier one serving the same function. The issue at the time was expediancy but that asside, we all prefer to work with quality tools, hence the desire for a more "suitable" material.

That said, ANYTHING that fits over the barrels and allows for affixing the adjustment screws - even a section of iron pipe - so long as the screws end up in the right places, will accomplish the same function. The fixture shown is for your own ideas and imaginations to picture what will work for you, not necessarily for exact replication.