Which is higher pressure?

[voiceofreason]

Which makes for greater pressure?

a jump from .223 (AE or Wolf Gold) to 5.56 NATO?

or

a jump from .223 (AE or Wolf Gold) to a .30 suppressor (.30 can on a 5.56 provides less back pressure)?

[StealthOPS32]

Are you asking which chamber pressure would be higher? I don't think adding a suppressor increases chamber pressure that much, though i could be wrong. The reason I say this is because the Back Pressure from the suppressor only pushed back to the chamber after the round has exited the barrel. And the Back Pressure exits the ejection port as the bolt is pushed to the rear. So I don't think there is that much pressure in the chamber by the time the next round is fired. But I'm interested to hear what others think. What is the purpose of your question by the way? Is there any importance to it, or just for the knowledge?

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[Clint]

What's the actual question?

Did you have a specific idea or plan in mind?

[voiceofreason]

I think I meant blowback. Not trying to dupe another thread I'm asking on. Sorry all.

Specific idea/plan is to put a .30 silencer on a M&P15 Sport 2.

Running .223 on the Sport is fine, but 5.56 is violent to say the least

I've read on this forum that the S&W AR series are over gassed (larger than Colt/BCM sized gas port) to run with cheaper/lower pressure ammo

I was told that it wouldn't be that much of an issue because the can is not sized for 5.56/.223 but .30 so the blowback shouldn't be too bad

given that I should be running a heavier buffer than the carbine one it came with (it's carbine length, not mid or rifle), I was thinking an H2 would work for everything from low powered .223 to 5.56 given that my 7k lighter in pressure mid length AR comes from BCM with an H buffer.

the question I'm wondering is whether using that same H2 buffer on the Sport… if adding a can using .223 ammo will affect it more than using 5.56 NATO without a can (I like IMI)

from there, I have a reference point as to what it might be adding if I was to run 5.56 suppressed over .223 suppressed

helps me to choose a buffer and understand the process. I'm hoping to use a single buffer (yes, it only takes seconds to swap out) for unsuppressed .223 to suppressed 5.56. I can ultimately run it suppressed in .223 only as well if there is too much of a gap to do it will a single buffer reliably.

thank you everyone for suggestions.

[StealthOPS32]

If your barrel is chambered in 5.56 then you should be able to safely run either .223 of 5.56 ammunition because 5.56 chambered are designed to handle the higher pressure. As I understand it, a lot of .223 chambered are also capable of firing 5.56 but I would verify with the manufacturer. The H2 is a good weight of buffer to use. My favorite is the Spikes Tactical ST-2 (it has Tungsten powder in it instead of metal balls so it's much quieter in my experience). The only thing I would really worry about with a suppressor is the gas blowback in your face. But don't let that discourage you from getting a suppressor, they are totally worth it!

So in conclusion, if I understand your question right, you want to be able to shoot .223 suppressed as well as 5.56 unsuppressed without changing buffers. If I got that right, I think the easiest solution is to get the can and the H2 buffer and if there are any cycling issues you can cheaply and easily try different buffers until you find the weight that works best. Hope this helps. If you have more questions, ask away.

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[MistWolf]

5.56 ammo has the potential for generating more gas as well as more pressure. More gas needs more time to vent. More pressure means events will happen quicker. That means 5.56 ammo has the potential to vent more gas sooner

[Clint]

There are two effects of adding a suppressor that might be referred to as blowback.


1) increased gas drive & higher cyclic rate
Technically, suppressors increase the total gas drive by slowing down and extending the "blowdown time"

2) gas to the face & extra crud exiting the chamber

In general, adding any suppressor to .223 produces more gas drive than switching to 5.56.

The sport will most likely run everything better with an H2 buffer.

[tom12.7]

There's a lot of variables to look at here. Makes a simple black or white answer less plausible for this.