I purchased a JG BAR-10 Airsoft "Sniper" rifle. It shoots those plastic 6mm BBs.
Well, if you take a cardboard box and cut a large
square hole in one side, and fill the box with old towels, you have
an INDOOR airsoft trap! I'll post a photo later.
It turns out that the JG BAR-10 is not the world's most accurate
airsoft. It's also not the most durable; the "metal" parts are mostly
cheap die-cast aluminum. I've already had to repair the scope mount (2
part epoxy works well), and sometimes the bolt snaps shut instead of
cocking properly. But it's ok for curing cabin fever; you can shoot
indoors with it.
So, here's my super secret accuracy enhancer on the JG BAR-10: Unscrew
the outer barrel from the receiver, and wrap the threads in Teflon
tape. Go several wraps. Then, re-thread the barrel back into the
receiver. This keeps the barrel from waggling all around, and improves
the accuracy. If the magazine doesn't fit into the stock after you do
this, back off one turn on the barrel before re-inserting the barrel
stop screw.
Then, applying principles from spring powered air rifles (" pellet
guns "), do not hold the rifle tightly when
shooting. Instead, lay the stock loosely in the palm of your
hand. Groups will be MUCH smaller!
Update
Ok, the JG BAR-10 is pretty much an overpriced toy. The cocking
mechanism breaks frequently.
BUT, following the
example of the indoor trap, it turns out that you can shoot a pellet
gun indoors, using the same principle. Make a wooden box, add a few
layers of Duct Seal putty on the inside, and put your targets over the
front of that. Works great, and the putty stops the pellets.
Targets
I made up some paper targets that you can download freely as PDFs and
print out.