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Porting a 20" barrel

2K views 7 replies 7 participants last post by  BarryHalls 
#1 · (Edited)
i have looked at shotgun barrels in a number of online places. The only barrels I have seen that were ported were 24" or longer. Is there a practical reason for this, i.e. complete combustion of the gunpowder needs the longer barrel without ports? I have never shot a shortie, but i love the idea of being able to put a dozen into my mb and use it for defense around the house and utility building. I have not shot a shotgun very much, but i can see where having less muzzle rise would be a great advantage if you are in a situation that you have to fire a couple of times in rapid succession. I am interested in firing shortie slugs up to 70 feet or so.
 
#2 ·
other than you'll be deaf and blind and piss off anyone within 10' of you,,, no reason.

a shorter barrel will have more muzzle pressure than a longer barrel so the ports will be more efficient.
more efficient at pushing down and forward and more efficient in the other 3 departments too.

just as an off the top of my head number the muzzle pressure in a 20" barrel versus a normal 28" barrel will be almost double.
 
#5 ·
For the most part I ported hunting barrels, Remington 870s in 12 and 20...the one shorter shotty I ported was my Ithaca M37 Police 8-shot...it is one of the ones where you pull the trigger and keep shucking and it'll fire..this gun due to its stock design and light weight kicked like a mule. I did some research and lengthened the forcing cone by reaming and I ported the barrel on the top behind the front sight ...the port is a series of holes drilled in a trapezoidal arrangement and Yes, it and lengthening the forcing cone drastically reducted recoil...it is loud...but not so bad that it is uncomfortable...it is a home defense gun and not a range toy...never heard anyone complain it is offensive;)
 
#7 ·
When I shortened the 28" barrel of my Rem870 to 20", I ported it by simply drilling a group of holes in the top of the muzzle. Seemed to work a bit, but not good for night use. The flash is extreme.
 
#8 ·
The main reason is your ears and eyes. Longer barrels have lower pressure at the muzzle/ports and the blast ia farther from the shooter.

As you move all of those things closer to the shooter, the ports become pretty punishing on the eyes and ears compared to throwing all of the blast forward.

Kinda why mossberg discontinued those big barret style knox rolling thunder muzzle brakes.

Amazing for keeping the muzzle down and the recoil was eliminated, but as it turns out shoulders and wrists can take more punishment than eyes and ears.
 
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