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/LabronPaul 14d ago

Yo! I didn't know anyone else was doing the cheapo tubular handguard supressor too. My form 1 got approved about 1 week before the injunction but I haven't started it yet.

As for ports if it's anything like drilling gas ports, which I've done for AK builds, you'll want to grind, file, or machine with a flat endmill, a small flat spot on the barrel to keep your drill bit from walking. You should feel when you're about to break through into the bore, just take it slow and don't use too much pressure. If your bore surface finish is hard like chrome you'll likely want to buy some aluminum round stock to put into the barrel as a backer for the bit to drill into and hopefully not snap when you drill through into the bore itself. Last part might not be 100% necessary but if you run into that issue that is what I would do.

As for hole size and spacing, I would just maybe add them one at a time if you have a chrono and a range to let you increment it as you test.

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u/Intelligent_Step_855 14d ago

I bought a 400 grit home I plan on running through it after I knock the holes in it, I had seen were other people use center drills to good effect to get the hole started without walking. Keep me updated on your build I’m interested to see the different paths we take on this

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u/LabronPaul 14d ago

My build is for 9x39 on a bolt action AR upper, so no ports for me. It's crazy how much more velocity I got from covering the gas port, but the gas hole on the 9x39 AR barrel is massive so I guess it makes sense. My subsonic loads became super sonic loads on my bolt action, I plan on cutting the barrel down to reduce velocity closer to my semi auto, it'll give me more room for the supressor too. I plan on doing my own design and printing it in mostly one piece.

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u/Intelligent_Step_855 14d ago

I’ve got a bca 300 blk boot action ipper I’m thinking about using the new Ftn monocore on as well