RTI Transfer Port - Optimal Size

[lbc_PSI]

Curious if anyone has played with polishing or changing Transfer Port sizes on the RTI barrels..

I measured the TP on some of the barrels I have and found the following..

LW .30 is 0.223 x 0.223
LW .25 is 0.198 x 0.223
CZ .25 is 0.195 x 0.195

In the above, the first measurement is the "width" and the second is the "length".

Is there a formula for caliber to transfer port size?

Is there any advantage to the oval shape versus the round shape?

Is there any advantage to creating a wider/larger hole on the outside diameter of the barrel to create a "venturi" effect for the TP?

 

[lbc_PSI]

OK..searching gave a .70-75 percent of bore size for the port.

What would be the recommended tool or method to enlarge the port be?

I’m interested in what shape bit if a drill or mill is the most accurate method. Or, can hand tools like a small round file or hand crank drill..or Dremel maybe?

Polishing to finish the work?

 

[Vetmx]

I played around a good bit with my first two RTI’s. Hammer weights, springs and porting. What I learned is RTI pretty much did things right. With my P2 I don’t even think about trying to reinvent their product. If you are going to super oval your port, don’t get too close to the back of the seated pellet or the probe oring. RTI has your barrel port already making the most use of the port in the block.

 

[lbc_PSI]

Not going for a super oval. Just trying to make the CZ port the same size/shape as the LW. Round vs oval.

 

[Vetmx]

Dremel and a fine stone bit will get the job done. They aren’t aggressive so there’s no worry of them getting away from you or creating burs.