9mm/300blk silencer

[junkman1967]

I am submitting my first form 1 to build a silencer for a 9mm SBR I am going to building on another form 1 (once approved) My question is this. Is it possible to build the 9mm suppressor and also use it on my 300blk AR? I am wondering if the threads on the barrel are the same. Has anyone done this. I doubt I will shoot the 300blk suppressed very often, but would like to have the option without have to build a second suppressor. Thoughts? I won't be offended if you tell me I am crazy

Thanks

Joe

[noisecatcher]

You will want to use some kind of brake/flash hider mount because .300blk barrels are typically threaded 5/8-24 while 9mm barrels are often threaded 1/2-36 or 1/2-28.

[junkman1967]

That's what I was think, some kind of adapter to fit bot barrels. Do you see any other issues? Obviously the baffles and end cap would be sized for 9mm. Thanks for the input.

Joe

[noisecatcher]

Make sure bullets will fit through the hole you drill.

[junkman1967]

I'm going to drill it to accommodate a 9MM (.355), so then I should have no issues with the 300blk (.308). Once I get the form 1 back and start building it I will post pictures and ask for help I'm sure. Thanks.

[noisecatcher]

It's pretty common practice to make the hole a minimum of .050"-.075" over the ACTUAL bullet diameter some guys go .100"+ over I encourage you to look at the completed builds page find a 9mm can and see if they shared what bore size they chose, if not you can ask them directly on their build thread or via PM what size they used.

[junkman1967]

Thank you for all the info, will do.

[tmc4065]

I'm going to drill it to accommodate a 9MM (.355), so then I should have no issues with the 300blk (.308). Once I get the form 1 back and start building it I will post pictures and ask for help I'm sure. Thanks.

If you were going to wire EDM it and have the straightest/perpendicular/concentric bore possible, I still don't know that I would venture under 10mm/.394 . . . I guess if you didn't care about blowing the thing up or maybe the first k or baffle in the stack . . .

10mm is very common if you have decent machinery and feel that you can hold concentricity well in your setup.

[junkman1967]

Great point. I just received the form 1 today exactly 6 months from the day I filed it. Now the fun begins

[John A.]

I've done a few 9mm cans now and to be honest, I'm considering a 300 specific suppressor for it to try to get it more quiet.

It's not really bad now, but the first round pop annoys the crap out of me, and from what I see online, is very common even with most commercial cans so I am thinking about doing a BLK specific build, which would also let me reduce the suppressor bore size more, which may help a little bit there too.

BTW, I'm using 60 degree cones in the latest 9mm can, and stepped baffles in the first.

To be perfectly honest, the first one has a better sound to my ear, but in all fairness, it's larger diameter (inside and out) and about 3 inches longer and about 4 more baffles, so perhaps that has something to do with why it sounds a little better too.

[yondering]

It's not really bad now, but the first round pop annoys the crap out of me, and from what I see online, is very common even with most commercial cans so I am thinking about doing a BLK specific build, which would also let me reduce the suppressor bore size more, which may help a little bit there too.

Use a smaller blast chamber. That seems to be one of the biggest factors in frp.

[John A.]

The expansion chamber in the newest one is already rather small. It's not much more than a 1/2 inch. And the cone itself also takes up much of that area too. I was actually worried that it would be too constrictive and gassy.