Thread: Some new calibres for custom builds

I had an interesting day at the range yesterday, I had four unfired rifles, three of them with calibres most likely unfired in NZ before ?

All the speeds quoted are from a Oehler 35p & are approximate at this stage until the rifles are finished, fluting etc & I use my pressure testing gear to get final safe/conservative pressures/velocities.

The first was a 280ai on a T3
162s going 2850-2900 with 20-21" barrel, recoil with the T2 muzzle brake was almost non-existent

Then I fired the 6-204 Ruger, once again a T3 with a Trueflite barrel std 22" T3 profile.
75 V-max at 32-3300
80 Gmx at 31-3200
87 SP at 30-3100
I'm very happy with this rifle it wants to shoot sub 1/2moa & with less than 30grains of powder it goes very well compared to a 243 & would be very quite suppressed

The 7-375 Ruger was next Rem 700 SPSS 25.5" barrel with T2 brake.
75-85 grains of powder.

162 A-max at 32-3250
180 Hybrid at 31-3150

Then finally the 30-375 Ruger Rem 700 SPSS 26" barrel with T2 brake.
75-85 grains of powder.

208 A-max at 30-3100
230 Hybrid at 29-2950

The 375 Ruger cases are showing great promise, with performance between the 7mmRM & 7mm Rum and 300win & 300 Rum

Burning a relatively small amount of powder for the velocities achieved should mean they last substantially longer than their bigger cousins.

I will post pictures & more info when I finalise them, cheers.