modding the Mossberg SA 28 shotgun

[JohnW]

I’m planning to widen the gas ports on my SA28 by about .002" to help it cycle more reliably. based on my measurements, I need a 2.75 mm (.1083") HSS jobber drill bit
the catch is the length. I need something with at least a 60 mm (roughly 2.4") overall length to reach the ports properly

does anyone have a source for metric bits in specific lengths like this?

 

[True American]

Try McMaster-Carr or MSC, also search aircraft-length metric HSS bits from industrial suppliers.

 

[shotgunTeam]

@JohnW maybe it's easier to find a 7/64. it's only .001 inch larger than your target size

 

[theBo555]

Before you drill, have you tried a letter-size 7 bit? It’s .1100", which is just a hair over your 2.75mm target. It might be easier to find in a long-reach version than a true metric 2.75mm.

Also, definitely use a drill press. a hand-drilling gas ports is a recipe for a broken bit stuck in your barrel

 

[BryanL]

You can also try industrial tool suppliers, long‑reach metric HSS bits (60 mm+) show up there more often than in consumer sets.