7.5" suppressed?

[gober13]

Was thinking about building a 7.5" .223 upper. Anyone know if its ok to shoot .223 from a 7.5" through a aac sdn6? Seen websites that say 7.5" is ok but aac says 10" minimum. My other question is i read that .223 has less pressure than 5.56 and is closer to .300 blk pressure anyone know anything about this? Thanks

 

[sparked1]

SAAMI pressure specs are easy to lookup, and I would trust manufacturer’s recommendations over what I read on the internet. It’s probably fine for occasional shooting, but I wouldn’t risk it on something where it cost me a year and a stamp. YMMV.

 

[gober13]

SAAMI pressure specs are easy to lookup, and I would trust manufacturer’s recommendations over what I read on the internet. It’s probably fine for occasional shooting, but I wouldn’t risk it on something where it cost me a year and a stamp. YMMV.

Yeah. Thats why i was asking about the pressures. Aac says 10" for 5.56 but if i only shoot .223 with pressures closer to .300 blk would it be the same? Is pressure the only factor in minimum barrel length?

 

[sparked1]

Yeah. Thats why i was asking about the pressures. Aac says 10" for 5.56 but if i only shoot .223 with pressures closer to .300 blk would it be the same? Is pressure the only factor in minimum barrel length?

If you’ve ever shot a non-suppressed SBR you understand how loud they can be. I think the barrel length recommendation has more to do with how effective the can will suppress the sound. At 7 1/2 inches a 5.56 round may be so loud that it won’t be sufficiently suppressed when compared to a 10+ inch barrel. That’s my speculation of course, so I would just call AAC and ask them. Or wait for more knowledgeable guys on here to chime in.

 

[rOmiLaYu]

Yeah. Thats why i was asking about the pressures. Aac says 10" for 5.56 but if i only shoot .223 with pressures closer to .300 blk would it be the same? Is pressure the only factor in minimum barrel length?

No, pressure is not the only difference. Baffle erosion due to unburnt powder is a major concern on a rifle so short.

As to SAAMI specs, all three calibers you mentioned have the same max rating of 55,000PSI. So they should be, ostensibly, interchangeable as far as what is "safe" for the can.

Having said all of that, corking a 7.5" barrel is pointless in my opinion. You'll still need earpro to shoot it and you'll damage your can and rifle at an excellerated rate over and against, say, a 10" or 14" barrel.

 

[gober13]

No, pressure is not the only difference. Baffle erosion due to unburnt powder is a major concern on a rifle so short.

As to SAAMI specs, all three calibers you mentioned have the same max rating of 55,000PSI. So they should be, ostensibly, interchangeable as far as what is "safe" for the can.

Having said all of that, corking a 7.5" barrel is pointless in my opinion. You'll still need earpro to shoot it and you'll damage you can and rifle at an excellerated rate over and against, say, a 10" or 14" barrel.

Ok. Thanks

 

[rOmiLaYu]

If you’ve ever shot a non-suppressed SBR you understand how loud they can be. I think the barrel length recommendation has more to do with how effective the can will suppress the sound. At 7 1/2 inches a 5.56 round may be so loud that it won’t be sufficiently suppressed when compared to a 10+ inch barrel. That’s my speculation of course, so I would just call AAC and ask them. Or wait for more knowledgeable guys on here to chime in.

This. All day long.

For me, the only purpose a suppressor serves is to get the rifle or handgun below 140db's. If it can't do that, I don't see the point...the suppressor then just becomes a NFA muzzle device (which it already is, arguably). A 7.5" AR is ear splittingly loud...even when you double up on earpro.

 

[sparked1]

This. All day long.

For me, the only purpose a suppressor serves is to get the rifle or handgun below 140db's. If it can't do that, I don't see the point...the suppressor then just becomes a NFA muzzle device (which it already is, arguably). A 7.5" AR is ear splittingly loud...even when you double up on earpro.

Not sure which is more unnerving at the range, someone that doesn’t know what they’re doing in the stall next to you, or someone mag dumping an SBR next to you. Damn that’s annoying.

 

[akitaems]

i debated rvis on my 7.5". finally went with the longer KAK muzzle device. does push everything forward, can shoot without a glove on front hand, and makes it more "manageable" for the sound/flash....but the RSO's still wont go in the indoor range with me...lol

 

[rOmiLaYu]

Not sure which is more unnerving at the range, someone that doesn’t know what they’re doing in the stall next to you, or someone mag dumping an SBR next to you. Damn that’s annoying.

Yup.

Almost as annoying as @Hayata and his Miculek muzzle brakes.