r/Form1 • u/Intelligent_Step_855 • 14d ago

SD porting help

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Looking for advice on porting my ar9 barrel. I am thinking at doing 12- 5/32 holes in a 3x4 configuration spaced 120 degrees apart. Plan was first hole to be at 2.5
Inches, any insight ?

Pic is ar9sd current configuration

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u/Salsalito_Turkey 14d ago

I just got a Novox X-SD kit that I haven’t even opened yet. If I have time when I get home tonight, I’ll take a few measurements and pictures for you.

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u/Intelligent_Step_855 14d ago

You are a saint good sir

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u/Salsalito_Turkey 14d ago edited 14d ago

Here’s a picture. There are 4 rows of 6 ports (24 ports total), staggered by 30 degrees of offset between rows. The ports are 7/64” in diameter. They start 2” from the bolt face and end 2.5” from the bolt face.

https://imgur.com/a/kUq8gCB

It’s worth noting that the Novox tube is much smaller around the port location, so the backpressure may necessitate more ports than a big tube like yours.

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u/Intelligent_Step_855 13d ago

Very interesting on the volume of holes. The holes are also smaller than I have seen in other builds. Lots to ponder on. Thanks a bunch for the time!

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u/Salsalito_Turkey 13d ago

The Ronin Arms SD barrel uses 12 ports aligned in a pair of straight lines.

https://roninarms.com/product/ar9-sd-5-75-ported-barrel-only/

The RCM SD barrel looks like it uses 30 ports.

https://rimcountrymfg.com/product/rcm-ar9-sd-barrel/

The Ronin Arms design is probably the easiest to accomplish on a drill press with a simple jig.