July 6th, 2019

Don’t Roast Your Ammo — Watch Temps in Hot Summer Months

Heat Map USA color chart

Well folks, it’s July 6th already — the means we’re moving into “peak heat” summer conditions. It’s vitally important to keep your ammo at “normal” temps during the hot summer months. Even if you use “temp-insensitive” powders, studies suggest that pressures can still rise dramatically when the entire cartridge gets hot, possibly because of primer heating. It’s smart to keep your loaded ammo in an insulated storage unit, possibly with a Blue Ice Cool Pak if you expect it to get quite hot. Don’t leave your ammo in the car or truck — temps can exceed 140° in a vehicle parked in the sun.

Ammo cool storage

Bosch Insulated tool caseTo learn more about how ambient temperature (and primer choice) affect pressures (and hence velocities) you should read the article Pressure Factors: How Temperature, Powder, and Primer Affect Pressure by Denton Bramwell. In that article, the author uses a pressure trace instrument to analyze how temperature affects ammo performance. Bramwell’s tests yielded some fascinating results.

For example, barrel temperature was a key factor: “Both barrel temperature and powder temperature are important variables, and they are not the same variable. If you fail to take barrel temperature into account while doing pressure testing, your test results will be very significantly affected. The effect of barrel temperature is around 204 PSI per F° for the Varget load. If you’re not controlling barrel temperature, you about as well might not bother controlling powder temperature, either. In the cases investigated, barrel temperature is a much stronger variable than powder temperature.”

Powder Heat Sensitivity Comparison Test

Our friend Cal Zant of the Precision Rifle Blog recently published a fascinating comparison test of four powders: Hodgdon H4350, Hodgdon Varget, IMR 4451, and IMR 4166. The first two are Hodgdon Extreme powders, while the latter two are part of IMR’s Enduron line of propellants.

CLICK HERE to VIEW FULL TEST RESULTS

The testers measured the velocity of the powders over a wide temperature range, from 25° F to 140° F. Hodgdon H4350 proved to be the most temp stable of the four powders tested.

Precision Rifle Blog Temperature Stability test hodgdon varget H4350 Enduron IMR 4451

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July 6th, 2019

How To Clean Rifle Barrels Effectively and Efficiently

Criterion Barrels Cleaning Clean Solvent rod guide Hoppes Wipe-Out

This article comes from the Criterion Barrels website. It provides good, conservative advice about barrel cleaning. Understand that cleaning methods may need to be adapted to fit the amount and type of fouling (and the particular barrel). In general, we do try to minimize brushing, and we follow the procedures Criterion recommends respecting the crown/muzzle. We have also had very good success using wet patches followed by Wipe-Out bore foam. Along with the practices outlined by Criterion below, you may want to try Wipe-Out foam. Just be sure to use a fitted cleaning rod bore guide, to keep foam out of the action recesses and trigger assembly.

The above video shows how to apply Wipe-Out or other bore-cleaning foam. We use a slightly different method. First, we use 3-4 wet patches to remove loose carbon fouling. Then we apply the foam as shown, but usually from the muzzle end (with bore guide in chamber). Here’s the important point — after 20-30 minutes, once the bubbles have dissipated, we apply the foam a second time, getting more of the active ingredients into the barrel. We then patch out, as shown, after 3-4 hours.

What is the Best Way to Clean a Rifle Barrel?

We are asked this question quite frequently alongside requests for recommended break-in procedures. Improper barrel cleaning methods can damage or destroy a barrel, leading to diminished accuracy or even cause a catastrophic failure. When it comes to barrel maintenance, there are a number of useful techniques that we have not listed. Some techniques may work better with different barrel types. This series of recommendations is designed to incorporate a number of methods that the Criterion Barrels staff has used successfully both in the shop and on their personal rifles. Please feel free to to list your own recommendations in the below comments section.

We recommend the use of the following components during rifle cleaning:

• Cloth patches (sized for the appropriate caliber)
• Brass jag sized properly for your bore
• One-piece coated cleaning rod
• General bore cleaner/solvent (Example: Hoppes #9)
• Copper solvent of your choosing (Example: Sweets/KG 12)
• Fitted cleaning rod bore guide
• Plastic AP brush or toothbrush
• Q-Tips
• Plastic dental picks
• CLP or rust preventative type cleaner

There are a number of schools of thought relating to the frequency in which a barrel should be cleaned. At minimum we recommend cleaning a barrel after each shooting session to remove condensation, copper, and carbon build-up. Condensation is the greatest immediate threat, as it can cause the barrel to rust while the rifle sits in storage. Copper and carbon build-up may negatively impact future barrel performance, increasing the possibility of a failure in feed or function. Fouling should be removed whenever possible.

The below tips will help limit the wear of different parts of your barrel during routine maintenance, helping extend the life of the barrel and improving its performance.

The Crown
The crown is the portion of the barrel where the bullet loses contact with the lands and grooves and proceeds to exit the firearm. The area most critical to accuracy potential is the angle where the bullet last touches the bore of the barrel.

Avoid damage to this area by using a plastic toothbrush and CLP type cleaner to scrub the crown from the exterior of the barrel. Even the most minimal variation in wear to the crown will negatively impact barrel performance, so be careful to avoid nicking or wearing away this part of the barrel.

Reducing Cleaning Rod Wear to the Crown
When running a patch through the barrel, place the muzzle about a ¼” from a hard surface that runs flat at a perpendicular angle to the cleaning rod’s direction of travel, like a wall or the edge of a work bench (pictured). When the jag impacts the hard surface, retract the cleaning rod and remove the patch.

By withdrawing the jag prior to its exit from the barrel, you are limiting the possibility of the brass dragging upon the crown if the rod is at all bent or misaligned. The soft cloth patch will continue to serve as the point of contact between the jag and the barrel, minimizing potential wear.

If possible, insert the rod through the chamber, pushing it forward toward the muzzle. Some rifles, such as the M1 Garand or M14, will require you to insert the cleaning rod through the muzzle. In these situations the use of a cleaning rod guide is recommended to limit the friction placed upon the crown.

Avoid using cleaning rod segments for scraping carbon from the recessed muzzle of an AR-15 barrel. We used this trick in the Marine Corps to impress the armorers and NCO’s with the cleanliness of our muzzles, but it likely played a significant role in reducing the service life of the rifle barrel in question.

Use a Q-Tip soaked in solvent to remove any copper or carbon residue from the recessed muzzle of an AR-15 barrel. A little bit of remaining carbon on the face of the muzzle will not negatively affect bullet travel so long as the crown edge remains consistent around the circumference of the bore.

The Lands and Grooves
This portion of the barrel may experience reduced efficiency due to copper fouling and cleaning rod damage. If copper fouling takes place during the initial break-in of the rifle, make sure to check our barrel break-in article.

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July 6th, 2019

Wind Reading Resource — The Wind Book for Rifle Shooters

wind reading book Camp Perry Miller Cunningham

“The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.” — William Arthur Ward

Readers often ask us: “Is there a decent, easy-to-comprehend book that can help my wind-reading?” Many of our Forum members have recommended The Wind Book for Rifle Shooters by Linda Miller and Keith Cunningham.

New Hardback Edition Releases February 19th
A NEW hardback edition of The Wind Book will released on February 19, 2019. This 152-page book, first published in 2007, is a very informative resource. But you don’t have to take our word for it. If you click this link, you can read book excerpts and decide for yourself. When the Amazon page opens, click the book cover (labeled “Look Inside”) and another screen will appear. This lets you preview the first few chapters, and see some illustrations. Along with the new hardback edition ($21.99) Amazon offers a Kindle (eBook) edition for $14.99.

Other books cover wind reading in a broader discussion of ballistics or long-range shooting, such as Applied Ballistics for Long-Range Shooting by Bryan Litz. But the Miller & Cunningham book is ALL about wind reading from cover to cover, and that is its strength. The book focuses on real world skills that can help you accurately gauge wind angle, wind velocity, and wind cycles.

All other factors being equal, it is your ability to read the wind that will make the most difference in your shooting accuracy. The better you understand the behavior of the wind, the better you will understand the behavior of your bullet. — Wind Book for Rifle Shooters

wind reading book Camp Perry Miller Cunningham

The Wind Book for Rifle Shooters covers techniques and tactics used by expert wind-readers. There are numerous charts and illustrations. The authors show you how to put together a simple wind-reading “toolbox” for calculating wind speed, direction, deflection and drift. Then they explain how to use these tools to read flags and mirage, record and interpret your observations, and time your shots to compensate for wind. Here are two reviews from actual book buyers:

I believe this is a must-have book if you are a long-range sport shooter. I compete in F-Class Open and when I first purchased this book and read it from cover to cover, it helped me understand wind reading and making accurate scope corrections. Buy this book, read it, put into practice what it tells you, you will not be disappointed. — P. Janzso

If you have one book for wind reading, this should be it. Whether you’re a novice or experienced wind shooter this book has something for you. It covers how to get wind speed and direction from flags, mirage, and natural phenomenon. In my opinion this is the best book for learning to read wind speed and direction. — Muddler

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