XM177: 5.5" moderator straight wall or conical?

[Stopsign32v]

https://www.tntesales.com/xm-177-gau...der-phosphate/

https://www.tntesales.com/one-piece-...der-phosphate/

I've attached a picture of the conical inside version. Would this show any advantage over a straight wall ID 5.5" flash hider? I was thinking possibly more accuracy...

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[Stopsign32v]

I posted this in the Vintage section but realized it really is just a general question. FH is 5.5" long but there are two options...

https://www.tntesales.com/xm-177-gau...der-phosphate/

One is a straight wall inside (tube that meets the bore) and then there is the one below which is a conical tapering interior. What benefit would one have over the other? I asked TNT and they said "weight"

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[lysander]

I posted this in the Vintage section but realized it really is just a general question. FH is 5.5" long but there are two options...

https://www.tntesales.com/xm-177-gau...der-phosphate/

One is a straight wall inside (tube that meets the bore) and then there is the one below which is a conical tapering interior. What benefit would one have over the other? I asked TNT and they said "weight"

Capture.JPG

Well, an advantage is it looks like a suppressor for an XM177E2. It probably does not weigh any more than one of those either.

A disadvantage would be it will not reduce the over-pressure of a short barrel like the XM177E2 suppressor, and may not reduce flash to the same extent.

[Stopsign32v]

Well, an advantage is it looks like a suppressor for an XM177E2. It probably does not weigh any more than one of those either.

A disadvantage would be it will not reduce the over-pressure of a short barrel like the XM177E2 suppressor, and may not reduce flash to the same extent.

Maybe I read you wrong but if not, I want to clarify. These are the two flash hiders in question...Notice the drawing difference in them. Appearance and dimensions are identical. Only difference is the internal design.

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If you understood the differences then I misunderstood you

[Stopsign32v]

This is the most Mickey Mouse shit ever but I drew some diagrams to explain my thoughts here. Technically wouldn't the conical FH be more accurate due to the gases being controlled in a better design and not just floating around in the chamber?

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[C-grunt]

My guess is the full diameter one might give you a slight boost in back pressure like the old Noveske Flaming pig. But the more turbulent gas release might result in more flash.

But I also wonder if the full diameter resign is just a newer production design to eliminate the step down design to save time/cost?

[Stopsign32v]

Maybe I should buy both and do a comparison at the range before pinning and welding. I'm mostly concerned with accuracy. I'll just get both and make a thread on my findings.

[lysander]

A muzzle device with an enclosed expansion chamber might be classed a suppressor by the ATF . . .

Or are you talking about something like this? It that case there wouldn't be much, if any difference, other than weight.

[sinister]

The Griffin XM Linear Comp had a single baffle and is effective giving you back-pressure (for short barrels) and a little flash suppression.



A straight extension serves as a "Viz Mod" (visual modification) but really doesn't do much for you (functionally). They were all the rage in the 80s up to the '94 ban.

If it's not machined true coaxially it can make for larger groups (like a bad crown).



What the Colt looks like inside (the Griffin looks like the external body on the right with no other baffling):



The AWC Hyperdyne was similar -- just a simple vented, closed tube:

[SteyrAUG]

The Griffin XM Linear Comp had a single baffle and is effective giving you back-pressure (for short barrels) and a little flash suppression.

A straight extension serves as a "Viz Mod" (visual modification) but really doesn't do much for you (functionally). They were all the rage in the 80s up to the '94 ban.

If it's not machined true coaxially it can make for larger groups (like a bad crown).

All that. Which is why you don't see XM177 type flash hiders on current 10.3/11.5 SBRs unless you are building a clone. For the same space you could mount a SF mini and get actual suppression.