February 8th, 2019

Cartridge Brass Wisdom for Semi-Auto Shooters by Zediker

Glen Zediker reloaders corner midsouth book AR-16 reloading semi-auto brass safety primer resizing

Here are highlights from an article Glen Zediker wrote for the Midsouth Blog. In this article Glen focuses on cartridge brass for semi-auto rifles, AR-platform guns in particular. Glen notes that semi-autos are tougher on brass than bolt-action rifles, so you need strong, durable brass, that has been full-length sized. And you need to be careful about neck tension, and primers. The article starts with Glen’s recommendations for tough, hard brass, and then includes the points outlined below.

Glen is the author of many excellent books on reloading. This article is adapted from Glen’s books, Handloading For Competition and Top-Grade Ammo, available at Midsouth HERE. For more information about other books by Glen, visit ZedikerPublishing.com.

Handloading for Competition
by Glen Zediker

The Competitive AR-15
by Glen Zediker

Top-Grade Ammo
by Glen Zediker

ONE: Full Length-Size Cases with Adequate Shoulder Set-Back

This is a huge source of debate… amongst my readers, but, since now I’m strictly speaking of semi-auto needs I doubt there will be much dissent: full-length resize all cases! Most cases from most semi-autos will emerge with a pretty well-blown case shoulder [taming down an excessively functioning gas system can reduce this]. Make double-sure you’re sizing the cases down to at least 0.003 clearance. If you don’t there are safety and function problems ahead.

TWO: USE Sufficient Neck Tension

The case neck [must be] reduced an adequate amount to retain the bullet. There should be a minimum net difference of 0.003 inches (three-thousandths) between sized outside case neck diameter and loaded round outside case neck diameter. [Editor — that means at least three thou of “grip”.] Reason: don’t take a chance of inadvertent bullet movement during the recoil and feeding cycles. That movement can be back or forward! It’s easily possible for a bullet to jump ahead when the inertia from the bolt carrier assembly chambers the next round.

Glen Zediker reloaders corner midsouth book AR-16 reloading semi-auto brass safety primer resizing

THREE: Use Tough Primers

Choose a tough primer! There’s a floating firing pin on an AR15 (M1A also) that is supposed to be held in check but that system doesn’t always work! If you load and extract a round and see a little dimple in the primer, that’s from the firing pin tapping off of it (again, created by inertia of bolt closing). A combination of a high primer and a sensitive primer cup assembly can create a “slam-fire”. Brands? CCI has some mil-spec primers that work well, and I’ve had great success with Remington 7-1/2. Some of the well-respected “match” primers are a little thin. The CCI and Remington also hold up well to the (sometimes) greater firing forces working on the primer (again, from the quick unlocking).

Here’s what I use from Midsouth.

FOUR: Be Sure to Seat Primers Below Flush

And, finally, make double-sure that each and every primer is seated to below flush with the case head! That’s true for any firearm (because it also means that the primer is fully seated) but imperative for safety in a semi-auto. This is especially an issue for those who use a progressive-type loading press.

Permalink Bullets, Brass, Ammo, Competition, Reloading 1 Comment »
January 15th, 2019

Case Priming Procedures — Insights from Glen Zediker

Primer Forster Co-ax priming tool
The anvil is the tripod-shaped thin metal piece protruding above the bottom of the primer cup. Getting the primer sitting fully flush on the bottom of the case primer pocket, without crunching it too much, requires some keen feel for the progress of primer seating.

top grade ammo book Glen ZedikerIn two informative Midsouth Blog articles, Glen Zediker offers helpful advice on priming. First he examines what happens to the primer itself as it is seated in the cup. Glen explains why some “crush” is important, and why you never want to leave a high primer. Glen also reviews a variety of priming tools, including his favorite — the Forster Co-Ax Bench Primer Seater. Then he offers some key safety tips. Glen provides some “rock-solid” advice about the priming operation. You’ll find more great reloading tips in Glen’s newest book, Top-Grade Ammo, which we recommend.

Priming Precision vs. Speed
Glen writes: “The better priming tools have less leverage. That is so we can feel the progress of that relatively very small span of depth between start and finish. There is also a balance between precision and speed in tool choices, as there so often is.”

Benchtop Priming Tools — The Forster Co-Ax
Glen thinks that the best choice among priming options, considering both “feel” and productivity, may be the benchtop stand-alone priming stations: “They are faster than hand tools, and can be had with more or less leverage engineered into them. I like the one shown below the best because its feeding is reliable and its feel is more than good enough to do a ‘perfect’ primer seat. It’s the best balance I’ve found between speed and precision.”

Primer Forster Co-ax priming tool

Primer Forster Co-ax priming tool

Load Tuning and Primers
Glen cautions that you should always reduce your load when you switch to a new, not-yet-tested primer type: “The primer is, in my experience, the greatest variable that can change the performance of a load combination, which is mostly to say ‘pressure’. Never (never ever) switch primer brands without backing off the propellant charge and proving to yourself how far to take it back up, or to even back it off more. I back off one full grain of propellant [when I] try a different primer brand.”

Primer Forster Co-ax priming tool

Priming Safety Tips by Zediker

1. Get a good primer “flip” tray for use in filling the feeding magazine tubes associated with some systems. Make double-damn sure each primer is fed right side up (or down, depending on your perspective). A common cause of unintentional detonation is attempting to overfill a stuffed feeding tube magazine, so count and watch your progress.

2. Don’t attempt to seat a high primer more deeply on a finished round. The pressure needed to overcome the inertia to re-initiate movement may be enough to detonate it.

3. Don’t punch out a live primer! That can result in an impressive fright. To kill a primer, squirt or spray a little light oil into its open end. That renders the compound inert.

4. Keep the priming tool cup clean. That’s the little piece that the primer sits down into. Any little shard of brass can become a firing pin! It’s happened!

These Tips on Priming come from Glen’s newest book, Top-Grade Ammo, available at Midsouth Shooters Supply. CLICK HERE to learn more about this and other publications from Zediker Publishing.

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