Chris Parkin puts the Burris XTR Signature Rings through their paces and, after reluctantly returning them to GMK, goes out and buys two pairs...
credit: Archant
LIKES: These will accommodate zeroing optics with limited internal mechanical travel; Add elevation without the need for a Picatinny Rail; Rotating the inserts will accommodate for windage issues too
DISLIKES: Nothing at all
VERDICT: I bought two pairs… need I say more?
RRP: £100 for 30mm, £130 for 34mm
www.gmk.co.uk
credit: Archant
IN DEPTH
Burris’s Signature XTR rings are available in 1”, 30mm and 34mm with multiple height formats for scope mounting on Picatinny rails or Weaver bases. They are supplied in a durable snap-lock case with T15 and T25 Torx keys as well as 10 ring inserts. These are the smart part because, like the older Signature Z models, they allow you to shim your scope’s tube without any fear of damage. The specific paired +/- inserts can be installed in various formats to correct for any zeroing problems your scope doesn’t have the mechanical range to compensate for, or to add elevation for an overall long-range capability on your rifle.
credit: Archant
Each ring has a 25mm long clamping surface with six screws to balance out the pressure exerted by the polymer inserts and these form what in engineering terms is called a ‘rose joint’, allowing axial movement while remaining radially stationary. When the two rings are effectively intentionally misaligned to alter the scope’s position, they still align with each other prior to tightening, without exerting bending stress on the tube. For a gun tester like me, they are very unlikely to ever damage or scratch a scope tube either.
I first used these mounts with a 34mm Steiner scope on a 20 MOA inclined Picatinny rail, but swapping the inserts around will allow up to 40 MOA of vertical, lateral or diagonal movement in 5 MOA steps. In a zeroing situation, this equates to approximately 40” of point of impact shift on a 100-yard target. The Pos-Align shims are supplied in pairs: +/-0, +/-5, +/-10 and two pairs of +/- 20 with thorough instructions. Exact ring spacing alters exact values slightly, but measurements are provided in the instruction booklet provided. I have personally bought two sets of XTRs for my internally-limited 30mm Yukon Photons that get swapped between guns regularly. Four simple clicks with a 4Nm torque wrench has them swapped in seconds, with perfect zero retention.