It always helps to be a little more clear on what you want other people’s opinions on. After reading several of your post, it appears that you plan to build a pistol. A 14.5” barrel with a pistol brace will give you something that is close to a carbide.
I much prefer a 10.5” barrel on a pistol. It keeps the gun short enough to use in the confines of a vehicle and long enough to use outside of a vehicle. If you have never taken a class where you fire from inside a vehicle, I highly recommend taking one.
I do prefer an SBR over a pistol due to the choice of better buttstocks and better stock adjustments. This is my 10.5” SBR. It wears a three prong flash hider now.
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My son shooting my SBR.
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I also have a 10” barrel carbide with a pin and welded flash hider. It a super fun gun to shoot.
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