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August 13th, 2023

Calculate True Elevation Changes with Burris Signature Rings

Burris signature rings inserts

Burris Signature Rings with polymer inserts are an excellent product. The inserts allow you to clamp your scope securely without ring marks. Moreover, using the matched offset inserts you can “pre-load” your scope to add additional elevation. This helps keep the scope centered in its elevation range while shooting at long range. Additionally, with a -20 insert set in the front and a +20 insert set in the rear, you may be able to zero at very long ranges without using an angled scope base — and that can save money. (To move your point of impact upwards, you lower the front of the scope relative to the bore axis, while raising the rear of the scope.)

Burris Signature Rings

Insert Elevation Values and Ring Spacing
People are sometimes confused when they employ the Burris inserts. The inset numbers (-10, +10, -20, +20 etc.) refer to hundredths of inch shim values, rather than to MOA. And you need the correct, matched top/bottom pair of inserts to give you the marked thousandth value. Importantly, the actual amount of elevation you get with Burris inserts will depend BOTH on the insert value AND the spacing between ring centers.

Forum member Gunamonth has explained this in our Shooters’ Forum:

Working with Burris Signature Rings
Burris inserts are [marked] in thousandths of an inch, not MOA. To know how many MOA you gain you also need to know the ring spacing. For example, with a -20 thou insert set in the front and a +20 thou insert set in the rear, if the ring spacing is 6″, the elevation change will be approximately +24 MOA upwards.

Here’s how we calculate that. If you have a 2 X 0.020″ “lift” over a distance of 6 inches (i.e. 0.040″ total offset at 0.5 feet) that’s equivalent to 0.080″ “lift” over 12 inches (one foot). There are 300 feet in 100 yards so we multiply 0.080″ X 300 and get 24″ for the total elevation increase at 100 yard. (Note: One inch at 100 yards isn’t exactly a MOA but it’s fairly close.)

Here’s a formula, with all units in inches:

Total Ring Offset
——————– X 3600 = Change @ 100 yards
Ring Spacing

(.020 + .020)
—————– X 3600 = 24 inches at 100 yards
Ring Spacing: 6 inches

NOTE: Using the above formula, the only time the marked insert offset will equal the actual MOA shift is when the center to center ring spacing is 3.60″. Of course, you are not required to use 3.60″ spacing, but if you have a different spacing your elevation “lift” will be more or less than the values on the inserts.

Burris Signature Ring elevation windage change spacing insert

Permalink - Articles, Optics, Tech Tip No Comments »
April 15th, 2023

Burris XTR Signature Rings — Great for PRS/NRL Competitors

Burris Pos-Align XTR tactical Rings preload elevation

For years we have touted the advantages of Burris Signature rings, with polymer Pos-Align Inserts. PRS/NRL shooters take note — this technology is available in a beefier, heavy-duty ring system for tactical rifles. The impressive Burris XTR Signature Rings offer six (6) clamping bolts per ring plus strong, dual steel base-clamps that self-center on Weaver or Picatinny rails. These aluminum XTR Signature Rings provide strength and holding power, plus the key benefits of Pos-Align inserts. As impressive as XTR rings are — they aren’t that expensive, with 1″-diameter XTRs starting at about $90.00 per pair (30mm and 34mm XTRs cost a bit more).

The polymer inserts in Signature rings perform three key functions. First, the inserts provide full, uniform scope-to-ring contact, with no need for lapping. You get a very secure “grip” on your scope without ring marks. Second, the Pos-Align inserts can provide elevation “pre-load”. With eccentric (offset) inserts, you can raise the back of the scope relative to the front, gaining up to 54 MOA of built-in elevation, without the need for expensive tapered bases. Third, the offset inserts can be rotated clockwise or counter-clockwise to shift point of impact. This lets you zero your rifle easily while keeping the turrets in the center of their travel.

Burris XTR Signature Rings are offered in 1″, 30mm, and 34mm diameters, and three (3) different heights: 1″, 1.25″, and 1.5″. Each ring set includes two sets of concentric inserts and one set each of the following offset inserts: +/-5 MOA, +/-10 MOA, +/-20 MOA. These allow you to “pre-load” elevation and/or center up your cross-hairs.

– Pre-load Elevation. No need for expensive tapered bases for long-range shooting.
– Correct misalignment caused by off-center receiver holes.
– Correct for bases or rings being slightly off-center.

How to Pre-load Elevation
To add elevation, set the Pos-Align Offset Inserts to raise the rear of the scope and lower the front. As long as there remains sufficient clearance between the front objective bell and the barrel, Burris recommends lowering the front of the scope the most and raising the rear of the scope the least. The amount of actual elevation “pre-load” will depend on the ring spacing (see chart). In the illustration, with 4.75 inches between ring centers, a +/- 20 MOA pair in the front combined with a -/+ 5 MOA pair in the rear will yield +25 MOA of total elevation. (If the rings are positioned further apart, you’ll get less elevation pre-load.)

Burris Pos-Align XTR tactical Rings preload elevation

Using Inserts to Adjust Point of Impact in Any Direction
Although it is convenient and most understandable to refer to the ring inserts as a “bottom” or “top” insert, the inserts may be rotated to any angle within the scope rings. This allows the shooter to correct the point-of-impact in any direction. The drawings below show how the inserts can be rotated to induce both elevation and windage changes at the same time.

Burris Pos-Align XTR tactical Rings preload elevation

Product tip from Boyd Allen. We welcome reader submissions.

Permalink Competition, Gear Review, Optics No Comments »
June 23rd, 2019

Tough Burris Tactical Rings with Inserts — Best Option for PRS?

Burris Pos-Align XTR tactical Rings preload elevation

For years we have touted the advantages of Burris Signature rings, with polymer Pos-Align Inserts. PRS/NRL shooters take not — this technology is available in a beefier, heavy-duty ring system for tactical rifles. The impressive Burris XTR Signature Rings offer six (6) clamping bolts per ring plus strong, dual steel base-clamps that self-center on Weaver or Picatinny rails. These aluminum XTR Signature Rings provide strength and holding power, plus the key benefits of Pos-Align inserts. As impressive as XTR rings are — they aren’t that expensive, with 1″-diameter XTRs starting at about $90.00 per pair (30mm and 34mm XTRs cost a bit more).

The polymer inserts in Signature rings perform three key functions. First, the inserts provide full, uniform scope-to-ring contact, with no need for lapping. You get a very secure “grip” on your scope without ring marks. Second, the Pos-Align inserts can provide elevation “pre-load”. With eccentric (offset) inserts, you can raise the back of the scope relative to the front, gaining up to 54 MOA of built-in elevation, without the need for expensive tapered bases. Third, the offset inserts can be rotated clockwise or counter-clockwise to shift point of impact. This lets you zero your rifle easily while keeping the turrets in the center of their travel.

Burris XTR Signature Rings are offered in 1″, 30mm, and 34mm diameters, and three (3) different heights: 1″, 1.25″, and 1.5″. Each ring set includes two sets of concentric inserts and one set each of the following offset inserts: +/-5 MOA, +/-10 MOA, +/-20 MOA. These allow you to “pre-load” elevation and/or center up your cross-hairs.

– Pre-load Elevation. No need for expensive tapered bases for long-range shooting.
– Correct misalignment caused by off-center receiver holes.
– Correct for bases or rings being slightly off-center.

How to Pre-load Elevation
To add elevation, set the Pos-Align Offset Inserts to raise the rear of the scope and lower the front. As long as there remains sufficient clearance between the front objective bell and the barrel, Burris recommends lowering the front of the scope the most and raising the rear of the scope the least. The amount of actual elevation “pre-load” will depend on the ring spacing (see chart). In the illustration, with 4.75 inches between ring centers, a +/- 20 MOA pair in the front combined with a -/+ 5 MOA pair in the rear will yield +25 MOA of total elevation. (If the rings are positioned further apart, you’ll get less elevation pre-load.)

Burris Pos-Align XTR tactical Rings preload elevation

Using Inserts to Adjust Point of Impact in Any Direction
Although it is convenient and most understandable to refer to the ring inserts as a “bottom” or “top” insert, the inserts may be rotated to any angle within the scope rings. This allows the shooter to correct the point-of-impact in any direction. The drawings below show how the inserts can be rotated to induce both elevation and windage changes at the same time.

Burris Pos-Align XTR tactical Rings preload elevation

Product tip from Boyd Allen. We welcome reader submissions.

Permalink Gear Review, Optics, Tactical 3 Comments »