Do I need a 7.5" upper?

American Revival Apparel Company

T-Roy

Hunter
Jun 24, 2015
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So I've been thinking. I have a 7.5" 5.56 upper, a 10.5", a 14.5", 16" & 20". I use the 10.5 as a suppressor host, and the 7.5" sits on my SBR as my "truck gun"

On the other hand, I think I finally got my 7" 300 upper set up the way I like it.

So is there a point to keeping the short 5.56? By my research I should be able to throw 125gr slugs out of the 300 at close to 2000 fps, while I'll get what, 2200 out of 55gr with the 5.56?

So the 300 has more energy, less muzzle flash, better suppression, and all the 5.56 has to offer is cheaper ammo and marginally higher velocity(less drop), right?

Is there something I'm not considering, or should I ditch the the 7.5"?
 

Shemp

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55gr only does 2200 FPS out of a 7,5"? 53gr 5.45 dows nearly 2500 FPS out of an 8"...
 

T-Roy

Hunter
Jun 24, 2015
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55gr only does 2200 FPS out of a 7,5"? 53gr 5.45 dows nearly 2500 FPS out of an 8"...
I think, it's pretty anemic anyway. I've always read its below minimum velocity for fragmentation of military ammo. I keep my one mag of ballistic tip in it right now.

Sent from my SM-G900P using Tapatalk
 

Shemp

Boomerwaffen Fuddmander
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I think, it's pretty anemic anyway. I've always read its below minimum velocity for fragmentation of military ammo. I keep my one mag of ballistic tip in it right now.

Sent from my SM-G900P using Tapatalk

Interesting....that's why I like the 5.45. velocity don't matter for it to do what it needs to do. My Krink will be an inside 100 meter gun anyway.
 

T-Roy

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Jun 24, 2015
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A little better, according to this chart, but still nothing close to what the 300 produces as far as energy.
 

Shemp

Boomerwaffen Fuddmander
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Lol, that hasn't crossed my mind as an advantage

Now you got me thinking I should have gotten a 7.62 AK to SBR instead of my 5.45. I just have a mountain of 5.45 ammo but it seems that the 7.62 would have about 200 ft/# more energy. A loaded mag weighs 1.2 pounds more....which doesn't sound like a lot but an extra 3#s in a backpack all day can get heavy
 
Last edited:

T-Roy

Hunter
Jun 24, 2015
70
51
43
Now you got me thinking I should have gotten a 7.62 AK to SBR instead of my 5.45. I just have a mountain of 5.45 ammo but it seems that the 7.62 would have about 200 ft/# more energy. A loaded mag weighs 1.2 pounds more....which doesn't sound like a lot but an extra 3#s in a backpack all day can get heavy

The way you get different gun fever, if it wasn't me it would have been something else.

If you've got the ammo I'd stick with it, that's the one downfall of my plan. I will have a couple hundred rounds of 300, so when shit hit the fan that may become a throwaway upper once I get home.
 
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Shemp

Boomerwaffen Fuddmander
Kalash Klub
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Mar 24, 2015
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The way you get different gun fever, if it wasn't me it would have been something else.

If you've got the ammo I'd stick with it, that's the one downfall of my plan. I will have a couple hundred rounds of 300, so when shit hit the fan that may become a throwaway upper once I get home.

Yeah I'm sticking with 5.45....I got too much
 

T-Roy

Hunter
Jun 24, 2015
70
51
43
c368ec9fca2b32c9446bf26be3531b26.jpg


3cc40f83ac8819faa443d2d1f0fbea82.jpg


$450 if anyone's interested. Troy industries factory upper with Noveske flaming pig. No bolt carrier group, charging handle, sites, or vortex SPARC included