When the 7mm Remington Magnum was originally released, it was met with overwhelming demand.  Every rifle manufacturer rushed to offer rifles chambered for the new cartridge, and in the rush some of the chamber dimensions varied slightly from different manufacturers.  This variation in the 7mm Rem Mag chamber dimensions has carried on to today, and there is still more differences in the chamber dimensions than for virtually any other rifle cartridge. What’s a chamber print? A “chamber print” is an illustration of the chamber reamer used to cut a rifle’s chamber.  It contains all of the key dimensions related to ...

After I identified a promising range of powder weights using Audetter’s ladder test, my next step was to use Dan Newberry’s Optimal Charge Weight (OCW) Method to offset the “scatter node” drawback inherently present in the ladder test.  To learn more about that, read this article comparing the OCW method with the ladder test. The OCW method is based on the observation that there are some loads out there (like Federal’s match ammo for the 308) that shoot really well out of just about any rifle.  How can one recipe shoot so well out of so many different rifles?  Dan Newberry believes accuracy of ...

The first step in load development for my new custom 7mm Rem Mag started with gathering the real-world velocities I could expect out of three quality long range bullets I was considering. I then used those velocities to compare the ballistic performance between those three bullets, as well felt recoil during the test rounds. I eventually decided to pursure further load development for Berger’s 168gr VLD bullet over Hodgdon Retumbo powder because it struck the right balance for me between the competing characteristics (recoil, barrel wear, flat trajectory, low wind drift, ideal energy for medium sized game, etc). For more ...

I’ve found myself needing to reference this info a lot while making data cards. It indicates the standard atmospheric pressure at different elevations. Pressure can vary quite a bit from the “standard” listed here, and although that won’t make much of a difference at short or mid ranges … when you get out to 1,000 yards or beyond it can make a noticeable difference. If you know the specific pressure the day you are shooting, it could really help your ballistics tables be more accurate. Having a Kestrel that can measure the instantaneous pressure is the best solution. Altitude (ft) ...

The first step in load development for my new 7mm Remington Magnum (with a 27″ barrel) was to get a basic idea for the real-world muzzle velocities I could expect out of a few different high quality, very low drag bullets, so that I could compare them ballistically and decide which to pursure for further load development. I decided to try out the three bullets listed below after reading a great article on 7mm bullets by Nathan Foster. I actually took all of these readings with a BRAND NEW BARREL (some of the first rounds out of it), so they ...

I recently had a custom rifle built that was chambered as a 7mm Remington Magnum. I plan to use it as a dual-purpose rifle: Precision rifle matches (target shooting out to 1000 yards) Hunting (primarily whitetail & mule deer and the occasional wild hog) I did a ridiculous, almost embarrassing amount of research before landing on the 7mm Rem Mag cartridge. After losing a deer last year, I wanted to make sure it had enough energy to put an animal down quickly. There is no such thing as overkill. With that mindset, I actually started by looking at the 300 ...

“No mere gadget, the chronograph is one of the most powerful tools imaginable in load development and problem diagnosis. A bullet’s velocity is one of the major contributors to its behavior, and if you don’t know what its velocity is, you may never understand that behavior. But knowing why the bullet behaves as it does, you can take intelligent corrective action that wasn’t available to you before.” – Dan Hackett, Precision Shooting Magazine A chronograph can be a powerful tool … but if you get more than a few “ERROR” readings in a row, you may be tempted to put ...

I have needed the exact dimensions of both the RCBS Rock Chucker Supreme Press and RCBS Partner Press a few times, as I was working on custom ways to mount them (like this portable reloading press stand).  Unfortunately, RCBS doesn’t publish anything to help with that … so I made a template and thought I would share it in case it helps anyone else. Download RCBS Press Mounting Template with Dimensions  The mounting template, contains the exact dimensions related to the mounting surface, but here are a few more dimensions for presses that are also helpful (and not published anywhere). RCBS Rock Chucker ...

Creighton Audette came up with a method for developing precision rifle handloads that has been referred to by many names: Incremental Load Development Method (ILDM) The Ladder Test 20 Round String Method Unfortunately many of Audette’s original articles aren’t very accessible, so I wanted to provide a few resources that help flesh out the method to load development he proposed.  I recently tried it out, and although at first I admit I was a little skeptical … after seeing the real world results and some critical thinking about what we are really trying to uncover when doing load development, his ...

With the number of “overbore” rifle cartridges popular today, barrel erosion is becoming a hot topic.  For example, competitive shooters using a 6 PPC typically replace a barrel after 700-800 rounds, and a 6.5-284 might also need to be replaced before the 1,000 shot mark.  That means the cost to keep a good barrel on the gun could be 60-70¢ per shot before we even consider the cost of components like match-grade bullets, brass, primers and powder.  In reality, short barrel life could easily double your cost per shot.  So what can we do to prolong the accurate life of ...