PMM FREQUENTLY ASKED QUESTIONS.

WHAT GAS JETS DO I NEED?

There is no one answer to this question, factors such as barrel length, ammunition used, suppressor, air temp/pressure and how clean the rifle is will all be factors that play into the jet size that will work for your setup.  The best way to find out what size will work for you is by trial and error with a couple tests.
1. Load a full magazine for your rifle as well as one in the chamber for a total of 21 rounds(scar 17) or 31 rounds(scar 16).  Fire the rifle once paying attention to the ejection and make sure the next round in the magazine is stripped and loaded into the chamber.  If all looks good then move to #2
2. Now that the rifle has cycled another round, insert an empty magazine and conduct a lockback test by firing the rifle again.  If both these tests have passed you can move down a jet size and start over.  If your rifle has failed either of these tests, increase by a half jet size and conduct the tests again.

Scar 17 Factory jet size: 1.45mm (16" Barrel)
Scar 20 Factory jet size: 1.4mm (20" Barrel)
Scar 16 Factory jet size: 1.35mm (16" Barrel)

Below PMM Address all the nuances of the MK17 & MK20  FN SCAR Gas System

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WHERE ARE MY INSTRUCTIONS?

Please check the appropriate product page, we have readily available PDF versions of our instructions to minimize the waste of paper.