It's really hard to mess up a set of feeler gauges. I use BluePoint, but that's because I buy a lot of my tools off the Snap-On truck at work. These would likely do you just fine. Or pic your poison.Amazon.com

For an MP5, your range is .010"-.018" (.25mm-.45mm)

 

O'Reilly Auto Parts. I enjoy getting out of the house once in a while

Performance Tool Feeler Gauge W125C | O'Reilly Auto Parts

 

We don't have them around here. I'll check out Lowes at some point today maybe.

 

if you have a factory HK in 9 mm, chances are you don’t need any, but if you deal with older guns in rifle calibers, it’s worth having a set. Any set from an auto parts store is fine.

 

I have a BluePoint as well. They are a precision tool, but most are pretty much equal. They are also cheap.

I would recommend one if your firearm isn't an HK. Getting a baseline and knowing if you need to send out for warranty work is nice.

Edit: Repeated what others have said.

 

Little Chinese kids clone MAWLs -- I'm pretty sure they can make a decent feeler gauge...

That being said, my $8.99 Amazon one seemed to wok just fine; it was also slathered in oil. You know -- so the Chinese stainless doesn't rust.

 

i just bought some random ones on amazon, checked em with my calipers and they're pretty spot on

 

It's awesome that you're willing to invest in inspection tools!
Starrett makes both English and metric thickness gauge sets for around $90 per set. Mitutoyo or some of the German companies may also make sets.
Your grandkids will still be able to use them. You spent the money on an HK... don't cheap-out now and support China.

 

No well sorted hardware store around the corner? Or any store that might sell tools (tractor supply, car parts store etc.). Also saves you shipping, no need to wait and you get good support.
Bc don't support Amazon or Chynah.

 

I buy the kind with a way to remove the few sizes I need for my 90 series. I put it back together, put it back in the box. Give it to my brother in law at Christmas. He does not know what it is, or does, but I get credit for being a good guy.

 

Diabolically brilliant!

 

And you were expecting something else?

 

Yeah FYI many don't treat the steel on these, they expect them to be coated in automotive grease by the end user with use. It's just fin-blade sheet steel stock.
Buy cheap.