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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 »
June 23rd, 2019

Don’t Get Barrel-Busted! Federal Barrel Length Requirements

short barrel barreled rifle shotgun NSA tax stamp ATF legal brief guncollective.com

The Legal Brief is a feature of TheGuncollective.com that focuses on firearms rules and regulations. In this Legal Brief video, Attorney Adam Kraut explains key State and Federal regulations governing firearms, and explains how to ensure compliance with all applicable laws.

This five-minute video explains barrel length rules for rifles and shotguns, and also explains the best (and most fool-proof) methods to measure your barrel. In addition, the video explains how to measure firearm overall length. A rifle or shotgun which is less than 26 inches overall can also be classified as a “Short-barreled” rifle/shotgun subject to the NFA. NOTE: Under federal law “If the rifle or shotgun has a collapsible stock, the overall length is measured with the stock EXTENDED”.

Highlights of LEGAL BRIEF Discussion of Barrel Length and Firearm Overall Length

The ATF procedure to measure the length of a barrel is to measure from the closed bolt or breech face to the furthest end of the barrel or permanently attached muzzle device. ATF considers a muzzle device that has been permanently attached to be part of the barrel and therefore counts towards the length.

How to Measure Barrel Length: Drop [a] dowel or rod into the barrel until it touches the bolt or breech face, which has to be closed. Mark the outside of the rod at the end of the muzzle crown (if you don’t have a permanently attached muzzle device) or at the end of the muzzle device if it is permanently attached. Remove the rod and measure from the mark to the end of the rod. That is your barrel length[.]

Remember, if the barrel length is less than 16 inches, it is possible that the firearm could be a short barrel rifle (if you are building a rifle or it is already on a rifle) and if the barrel length is less than 18 inches, it is possible the firearm could be a short barrel shotgun (again if you are building a shotgun or it is already a shotgun). Both of these firearms would be subject to the purview of the National Firearms Act and would require the firearm to be registered accordingly.

How to Measure Overall Length:The overall length of your rifle or shotgun may also classify it as a Short Barrel Rifle or Short Barrel Shotgun. The overall length of a firearm is the distance between the muzzle of the barrel and the rearmost portion of the weapon measured on a line parallel to the axis of the bore. … If the rifle has a permanently attached muzzle device, that is part of the overall length. … If the rifle or shotgun has a collapsible stock, the overall length is measured with the stock extended.

READ FULL ARTICLE on Ammoland.com.

Links for this episode:

ATF Method for Measuring Barrel Length and Overall Length:
https://www.atf.gov/firearms/docs/atf-national-firearms-act-handbook-chapter-2/download
Firearm – 26 USC § 5845: https://www.law.cornell.edu/uscode/text/26/5845
Firearm – 27 CFR § 479.11: https://www.law.cornell.edu/cfr/text/27/479.11
Short Barrel Rifle – 18 USC § 921(a)(8): https://www.law.cornell.edu/uscode/text/18/921
Short Barrel Rifle – 27 CFR § 478.11: https://www.law.cornell.edu/cfr/text/27/478.11
Short Barrel Shotgun – 18 USC § 921(a)(6): https://www.law.cornell.edu/uscode/text/18/921
Short Barrel Shotgun – 27 CFR § 478.11: https://www.law.cornell.edu/cfr/text/27/478.11

Permalink - Articles, Tech Tip 2 Comments »