Someone explain this "theory" please.

[CKY_Alliance]

Ok so i see people say all the time on the forums that more porting on a barrel will decrease your air efficiancy...ok heres my problem with that...if the air is already in the barrel where the porting is then its going to escape one way or another...if there is no porting then itll go out of the front of the barrel..so someone please explian how this theory on more porting = less effiency is true. (<---i like these guys there always toasting)

[magmonkey]

it works like this

with porting you have loss due to air escaping from behind the ball,
meaning you have to turn your reg/velocity adjuster up higher to make 280-300 fps

now take the same marker and put a barrel with no porting on it and fire a ball over the chronograph.. you should see a higher velocity


so a barrel with no or less porting will allow you to run lower input preasure saving you air

[CKY_Alliance]

Oh i never thought of that makes sense.Thank you for clearing that up..all though i believe next time im at the field im going to test it.

[urbansix]

Could you then, in theory, take a externaly smooth yet ported barrel such as a SP All-american and tape it up, to get better efficiency, in exchange for , what?, more noise? Just a thought.

[CKY_Alliance]

well tape is peress(sp) so you would still lose soem air..but what would be the benefit just get a barrel with no porting...or you could weld the porta shut...that prolly would go over to well unless you could get in the barrel to smooth it.

[Lohman446]

It will cause a rise in velocity if nothing else is changed - I have in the past had to tape ported barrels in heavy rain when I did nto have any unported ones with me...

[Destructo6]

I believe velocity loss assumes that the barrel is the same diameter its entire length. For stepped barrels, porting after the oversize step shouldn't effect velocity much, if at all.

[VFX_Fenix]

If the portion of the barrel past the step isn't ported you'll still see an increase in velocity over the chrono vs. a ported version of that barrel though the increase will not be as significant.

Edit - Stepped barrels by their design are less efficient than similar barrels of reasonable lengths for the operating pressure of the gun in question which are not stepped or ported. This loss of efficiency is noted by a loss in muzzle velocity which then requires a higher opperating pressure to achieve the same muzzle velocity.

However Stepped barrels also lend themselves to more consistant muzzle velocities because they feel the effects of irregularities in air delivered to the ball less because of their inherently less efficient design. They also lend themselves well to barrels which are longer than would normally be efficient for the marker they're on because there's less of the barrel length that actually touches the ball (idealy).

[Spartan X]

Deffidently. When I use my 14" Boom,stick on my Merlin I shoot 280 on the penny. And when I switch to my 12" Lapco Big Shot, I'm shooting 315 if I do not turn the reg down.