August 20th, 2013

Eliseo Tubegun Chassis for Tikka T3 Now Available

The Tactical and Target T3 Tubeguns are here at last! Gary Eliseo of Competition Machine has announced that his new tubegun chassis for Tikka T3 actions “is now available in Target and Tactical versions”. The T3 kit will initially be right-hand only, set up for AICS short action magazines. This is a “no gunsmithing” installation — no modifications to the action are required and the chassis kit works with the factory T3 trigger and safety. Along with the new Target and Tactical versions, a lower-cost Light-Weight Hunter T3 Chassis is also offered (this will accept AR buttstocks).

Eliseo Competition Tubegun T3

Eliseo Competition Tubegun T3

Eliseo Competition Tubegun T3Tikka’s T3 action is rigid and robust. It cycles smoothly and has a short 75° bolt lift. The T3 features a Sako-style extractor, with angled-leading-edge bolt lugs for smooth lock-up. The T3 action can be installed in Gary’s Chassis Kit with either a recoil disc (and bolts) or glue-in action mounting. The Chassis Kit is designed to accept AR15 buttstocks.

Eliseo’s current T3 Chassis Kit is for right-hand short actions. However, Gary told us today that left-hand models will be included in the next production run this fall. He is also prototyping a long-action version.

Price for the Tactical model is $1020.00, with a rugged Cerakote finish. Price for the Target version is $925.00 with a powdercoat finish or $1000.00 with a Cerakote finish. The Light-Weight Hunter chassis (that accepts owner-installed AR-type buttstocks) is $685.00. Tikka T3 action and AICS 5-round or 10-round magazines sold separately. For more info, visit GotXRing.com, call 714-630-5734, or send email to: spraynandprayn [at] gmail.com . CLICK HERE for order page.

Eliseo Competition Tubegun T3

Permalink Gunsmithing, New Product 1 Comment »
August 20th, 2013

Burris Signature Rings — Calculating Actual Elevation Changes

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:

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.

Burris signature rings inserts

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
6

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.

Permalink Optics, Tech Tip 11 Comments »