March 23rd, 2018

Angular Measurement — Mil vs. MOA — What You Need to Know

Mil MOA reticle ranging PRS tactical minute angle precision rifle series
Visit PrecisionRifleBlog.com for a discussion of MIL vs. MOA.

Many guys getting started in long range shooting are confused about what kind of scope they should buy — specifically whether it should have MIL-based clicks or MOA-based clicks. Before you can make that decision, you need to understand the terminology. This article, with a video by Bryan Litz, explains MILS and MOA so you can choose the right type of scope for your intended application.

This March-FX 5-40x56mm Tactical FFP scope features 0.05 MIL Clicks.
Mil MOA reticle ranging PRS tactical minute angle precision rifle series

You probably know that MOA stands for “Minute of Angle” (or more precisely “minute of arc”), but could you define the terms “Milrad” or “MIL”? In his latest video, Bryan Litz of Applied Ballitics explains MOA and MILs (short for “milliradians”). Bryan defines those terms and explains how they are used. One MOA is an angular measurement (1/60th of one degree) that subtends 1.047″ at 100 yards. One MIL (i.e. one milliradian) subtends 1/10th meter at 100 meters; that means that 0.1 Mil is one centimeter (1 cm) at 100 meters. Is one angular measurement system better than another? Not necessarily… Bryan explains that Mildot scopes may be handy for ranging, but scopes with MOA-based clicks work just fine for precision work at known distances. Also because one MOA is almost exactly one inch at 100 yards, the MOA system is convenient for expressing a rifle’s accuracy. By common parlance, a “half-MOA” rifle can shoot groups that are 1/2-inch (or smaller) at 100 yards.

What is a “Minute” of Angle?
When talking about angular degrees, a “minute” is simply 1/60th. So a “Minute of Angle” is simply 1/60th of one degree of a central angle, measured either up and down (for elevation) or side to side (for windage). At 100 yards, 1 MOA equals 1.047″ on the target. This is often rounded to one inch for simplicity. Say, for example, you click up 1 MOA (four clicks on a 1/4-MOA scope). That is roughly 1 inch at 100 yards, or roughly 4 inches at 400 yards, since the target area measured by an MOA subtension increases with the distance.

one MOA minute of angle diagram

MIL vs. MOA for Target Ranging
MIL or MOA — which angular measuring system is better for target ranging (and hold-offs)? In a recent article on his PrecisionRifleBlog.com website, Cal Zant tackles that question. Analyzing the pros and cons of each, Zant concludes that both systems work well, provided you have compatible click values on your scope. Zant does note that a 1/4 MOA division is “slightly more precise” than 1/10th mil, but that’s really not a big deal: “Technically, 1/4 MOA clicks provide a little finer adjustments than 1/10 MIL. This difference is very slight… it only equates to 0.1″ difference in adjustments at 100 yards or 1″ at 1,000 yards[.]” Zant adds that, in practical terms, both 1/4-MOA clicks and 1/10th-MIL clicks work well in the field: “Most shooters agree that 1/4 MOA or 1/10 MIL are both right around that sweet spot.”

READ MIL vs. MOA Cal Zant Article.

Permalink - Articles, - Videos, Shooting Skills 4 Comments »
March 23rd, 2018

Magpul Pro 700 Chassis — $1K MSRP and Packed with Features

Magpul pro 700 prs tactical chassis alumninum stock

Magpul has released a new modular chassis that should generate interest in tactical and PRS circles. Priced at $999.95, the Magpul Pro 700 Chassis is expensive — you can buy a complete Ruger Precision Rifle for less than that. But it looks like it has some impressive features that may justify the cost. The buttstock section features fast, ambidextrous controls for LOP and cheek-piece height. The Pro 700 features a strong, internal aluminum sub-chassis, with an universal bedding block section that works with both right-hand and left-hand actions.

Magpul pro 700 prs tactical chassis alumninum stock

Video Shows Key Features of Magpul Pro 700 Tactical Rifle Chassis:

Magpul pro 700 prs tactical chassis alumninum stock

Q: So what do you guys think — Is this thing worth a grand ($1000)?

Magpul Pro 700 Chassis Features
— Anodized machined 6061-T6 billet aluminum V-bedding block, body, adjustment knobs and fore-end with high-strength, injection molded polymer body covers.
— Ambidextrous bedding block for left-hand or right-hand actions.
— Folding stock with push-button hinge has left- or right-folding capability.
— Stock won’t interfere with bolt handle when folded.
— Fixed Stock adapter for non-folding use.
— Overall LOP adjustment range is 13.25” – 15.125”
— Butt pad adjusts up 1.33″ and down .90″ and 5° left or right.
— Comb height adjustment has a 1” range with locking knob for cheek piece.
— Cheek riser features a 3-position fore/aft adjustment.
— Polymer grip with 5° forward edge sweep, with 3/4” fore/aft trigger-reach adjustment.
— M-LOK® slots on fore-end for accessory mounting.
— Integrated AICS-pattern mag well for AICS-pattern short action magazines.
— Large trigger guard allows use with gloves and aftermarket triggers.
— Low-profile, anti-snag ambidextrous magazine release.

Product find by EdLongrange. We welcome reader submissions.
Permalink New Product, News, Tactical 2 Comments »
March 23rd, 2018

Primer Pocket Rocket — Another Reason to Use Eye Protection

Primer Blown Gas defect winchester casehead

Our friend Grant Guess recently had a “close encounter” with a bad primer. An apparently defective primer caused part of the casehead on one of his rounds to blow out. This, in turn, allowed high pressure gas to vent through the damaged primer pocket. Take a good look, boys and girls. This is yet another very good reason to wear safety glasses. The cartridge was a 6.5-06, handloaded in necked-down Winchester-headstamp .270 Win brass. Grant reports:

“I had a blow through between the primer and the primer pocket today. The action was really smoking and I got a face full of gas. This was a reasonably light charge. Thank God for safety glasses.

I should also mention that it appears there is a 3/64 hole that is halfway between the primer and the primer pocket. Like it burned a small jet hole through both of them.”

Could this happen to you? It just might. On seeing this damaged case, one of Grant’s Facebook friends, Chris D., observed: “Search the internet, you will see a lot of these pin hole ‘in the corner’ failures. Obviously Winchester has some issues with the LR primers.”

Careful Examination Reveals Apparent Primer Defect
After this incident, Grant examined the damaged case: “I pinned the flash hole and it is not over-sized or under-sized. The primer clearly has an area where it had a defect. At [50,000 CUP], it doesn’t take much of a defect to cause issues. There was a slight bit of pucker-factor on the next shot….”

Primer Blown Gas defect winchester casehead

Permalink Bullets, Brass, Ammo, Tech Tip 5 Comments »