If you were going to build the most compact PDW based on the AR platform, what do you think the most practical caliber would be for SD/HD use, vehicle defense, etc. Not just a range toy, but for serious purposes. Would you consider a binary trigger?
Optimum Caliber for an AR based PDW.
- Thread starter nortac
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- #2
Of course availability and cost of the ammo would be a major factor, which would lead me towards 5.56/.223. Also the calibers in which there were short barrels offered.
556 needs a minimum barrel length to acht correct velocity. So compact, as in 9" to 13" would lend itself to 762x39 or 300 blackout. Each has it's merits. I would go Galil Ace 2 in 762 and short lol.
Personally I would go with one of my 6.5 Grendels, changing out to the shortest legal length for a carbine barrel and a collapsible stock. I like the cartridge, load with a good sp bullet, probably in the 120-130gr range, For close range should give excellent terminal ballistics.
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- #5
Just to clarify, I’m talking about a VERY short barrel, no more than about 7.5 inches. Up close and personal!
OkieStubble
Dirty Donuts are so Good.
You don’t make these OP questions very easy.
. First, let’s breakdown your original post.1. What do you think?
2. The most practical caliber for Home defense, self defense, vehicle defense, not just a range toy, but serious use.
3. Would you consider a binary trigger?
1. My thinking can be long and hard. It can also be all over the place. Maybe even a Bit heretic, but here it is for what it’s worth.
2. If we are strictly talking PDW? (I’m gunna use question marks, you’ll just have to get over it.)
To me, you described a very short barreled, very handy PDW. These usually are restricted to hand gun calibers. Depending on the barrel and overall length of a PDW, 9mm could be a perfect caliber. .223/.556 could be a perfect caliber. However, your OP wants it to be very flexible at the jobs it might do.
Depending on the job it could see, you could find yourself under calibered with a 9mm at distance and over calibered with a .556 in between vehicles with a very short barrel.
.300 Blackout from a very short barrel? I dunno, how short are we talking here? You made the question for this thread almost impossible by saying, 1. The most compact? 2. The most practical? 3. The most diverse use in many different scenarios and still be adequately equipped throughout the many different possibilities of use and scenarios?
Tough job…. The easy answer would be, whatever you happened to have in your hand at the time. Picking any caliber, is going to meet many of the criteria you suggest and not meet others.
My pick? The 5x7x28.
1. Is it a rifle caliber? Pistol caliber? Or something in between or both?
2. It definitely doesn’t pass the availablilty and practical price test of other calibers, but neither does .300 BO?
3. But diversity in use and number of practical scenarios? Very practical for all these uses.
Home Defense? It small lightweight high velocity will easily fragment and break up when hitting most other things not human.
Inbetween vehicles? Fast shooting and fast acquisition due to low recoil.
Distance? Not 556 distance, but will blow handgun and .300 out of the water. Effective terminal velocity’s at intermediate ranges.
4. So while practical at diversity in uses and ranges, also practical at being the only caliber needing to be carried?
A. 5.7 can be carried in the PDW and the sidearm, and a whole bunch of it can be carried. Makes it very practical imo.
B. Yes, it’s hard to find and expensive when you do, but you reload, right?
Regardless, I will fall back on my number 1 in my post,
“this is what I think.”
Almost forgot. 5.7 would absolutely rock with a binary trigger. The others? Not so much it would make a difference of having a binary or not.
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I want to build it myself, so I want it to be AR based. But thanks for the suggestions.
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- #8
Too long and I already got a 16 in. 6.5 G.
Discharging a rife round in a vehicle 
ouch
Ready made solution by B&T. The price tag is insane but perhaps some inspiration for your build…
bt-ag.ch
ouchReady made solution by B&T. The price tag is insane but perhaps some inspiration for your build…
B&T semi-automatic carbine SPC9 SD PDW G, Cal. 9x19mm
Perfect mixture: M4/AR style charging handle, M4 type lower for Glock magazines, telescopic stock and the provend APC PRO design. The SPC9 G is a highly interesting combination of proven features for those who prefer the charging handle at the rear end of the housing.
bt-ag.ch
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- #10
@OkieStubble , I had not considered 5.7x28. Are bcgs and barrels available for the AR platform? The cost and availability of the 5.7 x 28 ammo would be somewhat of a problem.
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If I went with 9mm, it would be a shorter version of what I already have and would be easy enough to build with another Aero Precision receiver set.
How short would that be? I haven’t found anything shorter yet but this is a range toy for me.
OkieStubble
Dirty Donuts are so Good.
I have no idea. I never considered the possibilities until considering the impossible list of wants from your OP….
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- #14
Not so impossible list of wants. Very compact, very short barrel, short range, not a "do all" like some of my other builds. I'm not looking to reach out beyond self-defense ranges.
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- #15
So, my existing 9mm AR pistol has a 10.5-inch barrel. The concept for this post is for something much shorter. This begs the question of why not just use a standard 9mm handgun. This leads me away from any pistol caliber PDW. I also want to avoid any braces or conflicts with ATF or SBR issues.
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- #16
Strike Industries have a receiver extension and buffer kit that is a couple inches shorter than the standard receiver extension. I have never used one or have any idea how well it works. Just something to think about.
www.strikeindustries.com
Strike Industries Pistol Buffer Tube
The Strike Industries Pistol Buffer Tube introduces added functionality to an often overlooked part of an AR pistol PDW. At an overall length of just over 5 inches, the pistol buffer tube reduces the pistol’s overall length. The pistol buffer tube comes complete with our proven tungsten filled...
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- #18
I just put Strike Industries carbine length buffer tubes on my two current AR pistols. Seem high quality. I've only put less than 100 rounds through my AR 9mm pistol. I have yet to shoot the 5.56 AR pistol with the new buffer tube. I'm sure it will do fine.
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- #19
CMMG has both complete AR pistol and bcg+barrel for sale in 5.7x28.I have no idea. I never considered the possibilities until considering the impossible list of wants from your OP….
OkieStubble
Dirty Donuts are so Good.
Boom! Think about it? Go get a five-seven pistol for a same caliber sidekick to go with your 5.7 PDW?
Shazam!
Gun Review: FN Five-seveN MRD Mk3 Pistol - The Truth About Guns
◀Previous Post Next Post▶ When FN created the latest generation of Five-seveN pistol, they didn’t just add an optic cut to the slide and call it good. The FN Five-seveN MRD (Micro Red Dot) is an evolved update to a unique handgun that many love and others can’t seem to figure out. The new...
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