Supersonic load on 4.5" barrel able to defeat IIIA body armor?

[bangbangping]

If it were me, I'd give up 3.5" of compactness for a 60% increase in energy. But then we may have different priorities.

Despite the energy losses, am I going to defeat IIIA or lower levels with supers through this 4.5" barrel?

I don't know. But you'd have a lot better chance with 60% more energy.

[rebel]

You are asking for absolutes on an unproven system. Assuming it could operate correctly, you could load for it, why would you need it for that? I'll answer any question to the best of my ability if you will answer mine. Be honest, no worries.

[Omega]

If it were me, I'd give up 3.5" of compactness for a 60% increase in energy. But then we may have different priorities.

Despite the energy losses, am I going to defeat IIIA or lower levels with supers through this 4.5" barrel?

Defeating most body armor depends on speed, so can that size barrel do this at your planned engagement range?

Level IIIA
9 mm FMJ at ~1,400 fps
(~427 mps)

.44 Magnum Semi-Jacketed Hollow Point at ~1,400 fps
(~427 mps)

And I believe it's 6 hits in a certain square inch which it must stop to be certified. But, it's no guarantee, I've had 5.56 both get defeated and get stopped by level IIIA panels. Didn't send any 30 cal at those panels, so not sure if some would of been stopped or not, but I can tell you that a perp would have to be real committed to keep going after getting hit with a rifle round, whether it gets stopped or not.

[10Driver]

Hey guys, this is my first post here!

I'm considering ordering a custom barrel from White Oak Precision with the follows specifications: 4.5” Medium Profile (.750”), Pistol Length Gas System, 1:12 twist, 300 BLK, 0.067" gas port diameter, 416R stainless steel (which would cost around 190 bucks).

Here's my doubt: I intent to shoot supersonic only, through a SIG SRD762 sound suppressor. But I'm not 100% sure that it will be able to defeat level IIIA armor. So, do any of you know if it would maintain soft armor piercing capabilities with such a tiny 4.5 inch barrel? Thanks in advance!!

Well, if nothing else, it’s quite the inauspicious entry onto the forum.


You’ve gotten my curiosity (and other things) up.

White Oak looks like they cater more towards rifles then 4.5” pistol gas barrels in 1:12 twist. Did they already agree to make that? With that gas port?

Do you have the SRD762 in hand and Sig has signed off on this application?

One other thing, have you fired a suppressed 4.5” 5.56?

[Ghost12three]

Hey guys, this is my first post here!

I'm considering ordering a custom barrel from White Oak Precision with the follows specifications: 4.5” Medium Profile (.750”), Pistol Length Gas System, 1:12 twist, 300 BLK, 0.067" gas port diameter, 416R stainless steel (which would cost around 190 bucks).

Here's my doubt: I intent to shoot supersonic only, through a SIG SRD762 sound suppressor. But I'm not 100% sure that it will be able to defeat level IIIA armor. So, do any of you know if it would maintain soft armor piercing capabilities with such a tiny 4.5 inch barrel? Thanks in advance!!

Well, if nothing else, it’s quite the inauspicious entry onto the forum.


You’ve gotten my curiosity (and other things) up.

White Oak looks like they cater more towards rifles then 4.5” pistol gas barrels in 1:12 twist. Did they already agree to make that? With that gas port?

Do you have the SRD762 in hand and Sig has signed off on this application?

One other thing, have you fired a suppressed 4.5” 5.56?

White Oak did agree, but could not provide data on the ideal gas port size. I did my own research and the best size for supersonic/ suppressed seems to be that. Same thing for twist rate: specifically for supers.

I've never seen such a tiny 5.56 barrel in person, but my interest is in the 300 BLK capabilities. The Firearm Blog has at least one video that I recall now, in which James shows a SIG MCX Rattler, with a barrel just one inch over 4.5, sporting the SRD762 can (everything goes as expected, with very good performance). No, I don't have that can in hand.

[Omega]

What other criteria are you considering besides being able to defeat Level IIIA armor? An FN 5.7×28mm pistol may have a better chance of doing that than a short barrel AR. But, if nothing else with an AR, all you'll be out is a barrel if it doesn't perform as you want.

[Ghost12three]

What other criteria are you considering besides being able to defeat Level IIIA armor? An FN 5.7×28mm pistol may have a better chance of doing that than a short barrel AR. But, if nothing else with an AR, all you'll be out is a barrel if it doesn't perform as you want.

I looked at the AR57 and CMMG MK57 Banshee. None have the ability to be so short while having a can attached, still being able to penetrate IIIA. They seem to need longer barrels to acceptable performance; "The ammo for the civilian market WILL NOT penetrate Level IIA and Level IIIA Kevlar, Kevlar 129 or Spectra vests"

Answering your question: it needs to have more energy and higher velocities from a smaller platform. The only benefit I see in 5.7x28 is the larger magazine capacity on the AR57 (but the reload time is longer and needs specific training - the MK57 can't take mags that hold more than 20 rounds: they won't cycle reliably.).

Your last comment about the barrel made me more optimistic about all this

[10Driver]

Hey guys, this is my first post here!

I'm considering ordering a custom barrel from White Oak Precision with the follows specifications: 4.5” Medium Profile (.750”), Pistol Length Gas System, 1:12 twist, 300 BLK, 0.067" gas port diameter, 416R stainless steel (which would cost around 190 bucks).

Here's my doubt: I intent to shoot supersonic only, through a SIG SRD762 sound suppressor. But I'm not 100% sure that it will be able to defeat level IIIA armor. So, do any of you know if it would maintain soft armor piercing capabilities with such a tiny 4.5 inch barrel? Thanks in advance!!

Well, if nothing else, it’s quite the inauspicious entry onto the forum.


You’ve gotten my curiosity (and other things) up.

White Oak looks like they cater more towards rifles then 4.5” pistol gas barrels in 1:12 twist. Did they already agree to make that? With that gas port?

Do you have the SRD762 in hand and Sig has signed off on this application?

One other thing, have you fired a suppressed 4.5” 5.56?

White Oak did agree, but could not provide data on the ideal gas port size. I did my own research and the best size for supersonic/ suppressed seems to be that. Same thing for twist rate: specifically for supers.

I've never seen such a tiny 5.56 barrel in person, but my interest is in the 300 BLK capabilities. The Firearm Blog has at least one video that I recall now, in which James shows a SIG MCX Rattler, with a barrel just one inch over 4.5, sporting the SRD762 can (everything goes as expected, with very good performance). No, I don't have that can in hand.

There is so much that I could say that I really don’t know what to say.

So, welcome to the forum.

If you do decide to undertake this build, I genuinely hope you’ll come back frequently and provide updates on your progress. Hopefully with pictures, videos and chronograph data.

I would be curious about one other thing. It sounds like you’d like a suppressed Rattler. Have you considered going down that path?

[dellet]

You will need to move the gas port back at least 1” from pistol length. A 4 1/2” barrel with a normal pistol length port location will only have about 1/8” of barrel in front of the port.



Keep in mind barrel length is measured from the bolt face.

Muzzle pressure with supers will increase somewhere between 3-5000 psi. to 20,000+ when going from a 5.5” barrel to a 4.5”. Basically about like a 300 Wmag with a 14-16” barrel.

[Ghost12three]

Well, if nothing else, it’s quite the inauspicious entry onto the forum.


You’ve gotten my curiosity (and other things) up.

White Oak looks like they cater more towards rifles then 4.5” pistol gas barrels in 1:12 twist. Did they already agree to make that? With that gas port?

Do you have the SRD762 in hand and Sig has signed off on this application?

One other thing, have you fired a suppressed 4.5” 5.56?

White Oak did agree, but could not provide data on the ideal gas port size. I did my own research and the best size for supersonic/ suppressed seems to be that. Same thing for twist rate: specifically for supers.

I've never seen such a tiny 5.56 barrel in person, but my interest is in the 300 BLK capabilities. The Firearm Blog has at least one video that I recall now, in which James shows a SIG MCX Rattler, with a barrel just one inch over 4.5, sporting the SRD762 can (everything goes as expected, with very good performance). No, I don't have that can in hand.

There is so much that I could say that I really don’t know what to say.

So, welcome to the forum.

If you do decide to undertake this build, I genuinely hope you’ll come back frequently and provide updates on your progress. Hopefully with pictures, videos and chronograph data.

I would be curious about one other thing. It sounds like you’d like a suppressed Rattler. Have you considered going down that path?

Yes, I have. But my heart broke when Tim from Military Arms Channel showed me how gassy that puppy is. I got really disappointed. Here is the link to the video in case you're interested: https://youtu.be/7b6vCcnZ2Qc