This is a work-in-progress, but I thought I'd share where I'm at in case it helps others. I had a few minor issues with the otherwise exceptional Mandalorian Rifle model by Rob Pauza:

• Rifle Stock: The stock is ~460mm long, and is cut in half (~230mm each). My printer (Prusa i3) only has 200mm of Z-height, so neither half will fit on my printer. Instead, I re-merged the two halves back together, then cut it in thirds instead (~153mm each). This will easily fit on nearly any printer now. Additional notes on this part:
  • I did NOT re-orient the stock parts back to the print-bed. You'll likely want to flip the two front-most stock parts onto their other cut face for best printing.
  • I extended the small dowel hole by 100mm, so instead of the recommended 1000mm x 8mm dowel, you'll instead need 1100mm.Should still work even with the original length, however.
  • I also used the same "Connectors" slots in the 3 pieces of the stock. Simply print two copies of the "Connectors" part from the original model to accomodate.
  • I also noticed upon re-merging the files that the "stock-back" file is slightly wider than the "stock-front", creating a slight lip where they join. I re-skewed "stock-back" to a much closer fit. The STL is very mildly distorted round the merged seam, but it should still print cleanly, and tidy up nicely with light sanding.

• Pew Pew End: The "Pew-Pew-End" part is taller than the standard i3-style build volume. However, being otherwise very narrow, it easily fits in the build volume if tilted at an angle. Normally, this can be challenging to print, so I added a little angled cylinder section to the bottom that gives a solid foundation, but it has a 0.2mm air gap from the actual part, and has a few tiny tabs attaching it to the actual part that snap off easily after printing.
  
  • It doesn't technically require supports, since it's printing at about a 45-degree overhang angle which most printers can handle. I added a couple narrow columns of support along the length to be sure it didn't topple over.
  • I recommend rotating the part so that it is leaning toward the part cooling fan for best overhang performance (e.g. base at rear of bed, and leaning toward the front for most printers).
  • Since it's printed sloped, use a smaller layer height than you might normally do for best surface finish (e.g. 0.1mm).

• Frame Part 2: The "Frame2" from the original model has no tolerance between it and the "Frame1" part, so it won't fit correctly and may bow outward. I trimmed 0.5mm off each interior side of Frame2 to provider better tolerancing. This part, like the original, requires supports.