Muzzle velocity loss after installing a barrel tuner

[JRS]

That is a bit odd. Not saying it can't somehow constrict the muzzle, but, the barrel would have to be mighty thin. For example, the starter ring gear on a flywheel. it is heated until it expands, then when it cools, it returns to it's original size. We do the same thing when we place the rings over the turbine shafts in the nuke plants. In both examples above, neither the flywheel, nor the turbine shaft dimension changes. Maybe Mike Ezell will see this thread and respond. He produces most excellent tuners.

 

[mac86951]

I'm assuming the tuner is not also a muzzle break, what is the center bore of the tuner? Would it be possible that if that the center bore of the tuner is near barrel bore diameter and no alternate exit for the gasses exists, the crown-tuner longitudinal location could be creating a volume pocket allowing the gasses ahead of the bullet? I ask because if it is not a brake/compensator, and center bore of the tuner is .310 or less I could see how the gasses are causing a slow down of the bullet on the rush to exit.

Maybe it doesn't matter, but its just a thought.

-Mac

 

[dannyjbiggs]

Whatever...I would like to witness that I have not detected any MV loss in any of my 7mm barrels employing a "screw on" barrel tuner.

Dan

 

[normmatzen]

Did you consider you are comparing shots without tuner averaging 47.4gr of Varget to shots with a tuner and average 47.55 gr Varget and you get an increase in 1% in MV. I don't know how linear the MV vs powder charge is, and I don't know how many shots you took with each condition (tuner vs no tuner) but if you didn't shoot above 40 shots, the statistics are not accurate to take the avg MV to the bank.

I'd say you don't have a problem?

 

[fgregorio]

Of course it matters Mac. The width of the inside of the tube that supports the weight forward of the muzzle is 0.6 inch.
I just dawned on me after reading your post that the barrel tuner is 2.5 inches long forward of the muzzle. I guess that the lost fps are hidden in there

 

[fgregorio]

Hi Norm,
Both ladder tests had exactly the same loads.
Shot 1- 46.1gr
Shot 2 - 46.2gr
Shot 3- 46.3 gr
And so on.
But...... The barrel tuner is a 2.5 inch long tube attached to the muzzle that disturbs the gas exit. Maybe the fps are lost there.

 

[fgregorio]

Danny, does any of your barrel tuners protrude over the muzzle?