Brain Dump: The 338 Gaillard Rifle Cartridge

What is the .338 Gaillard?

A wildcat cartridge developed by Ted Gaillard
What's a wildcat? Cartridges that are not officially registered with nor sanctioned by SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) are generally known as wildcats. Basically, you wont be seeing the 338 Gaillard cartridge on any store shelves, which is fine, as it is in the company of dozens (if not hundreds) of other excellent cartridges.
It was developed for accurate long range shooting (beyond 600 yards).
It's a belted magnum cartridge with excellent capabilities.
It has an improved shoulder.
Compared to it's parent cases, it has far less taper in the case wall.
It's a .338 (8.585 millimeters).
More case capacity than the standard 8mm Remington Magnum (my favorite parent case).
It can be developed from a number of existing cartridges. Many wildcats restrict the developer to only one parent case. The 338 Gaillard's parent case flexibility makes it easy to develop cartridges when certain cases may be hard to acquire. (see: What is involved in forming the brass for this cartridge?).

For all of its capabilities
The 338 Gaillard is suitable for game the size of Elk or larger. It is also great for deer when loaded with lighter bullets such as Hornady's 180 grain Interlock.
This cartridge is a very flat shooting cartridge, and therefore perfect for long range target shooting. Range permitting, you can shoot beyond 1000 yards quite accurately.
Shoots heavier .338 bullets at high velocities (surpassing the .338 Winchester Magnum).
Heavier .33-caliber bullets yield a great deal more energy and their larger diameter delivers a heavier blow than is possible with lighter calibers. The 338 Gaillard is obviously very powerful. When loaded with a typical 225 grain bullet it can surpass velocities of 3,000 feet per second (FPS) and deliver approximately a ton (2000 Foot Pounds) of energy at 500 yards. This makes it ideal for larger North American game. You can also enjoy the advantages of the heavier 338 bullet's wind bucking ability.
You might like wildcats. For the uninitiated, wildcats can be fun. I personally like forming cases, reloading, testing, and the other aspects of using a wildcat cartridge.
It is very accurate.
Brass is cheaper than the 338 Lapua (Using the 8mm Remington Magnum as a base cartridge)
There is a very good selection of .338 bullets available to the reloader, from a variety of manufacturers.

The recoil of the 338 Gaillard is very substantial and this cartridge is recommended to those who have experience with other big bore caliber Magnum rifles, especially those who found they could deal with pronounced recoil. NOTE: Okay, recoil is relative. Each individual perceives recoil differently. There are also other factors besides the cartridge that determine felt recoil, such as rifle weight and style.
You might not like wildcats. For the uninitiated, wildcats can be intimidating. You may not like forming cases, reloading, testing, and the other aspects of using a wildcat cartridge.
It uses more powder.
Since the cases are larger, cases will of course cost more than typical cases such as the .308 Winchester or the .223 Remington.

You can't just walk into your favorite gun store and buy boxes of 338 Gaillard cartridges, or pick up a new rifle chambered in the 338 Gaillard. You have to build your own rifle, or rechamber an existing rifle for this wildcat.
I have been informed that Redding provides reamers or dies.

Bullets ranging from 200-250 grains are likely the best, but there's no reason not load cartridges with lighter 180 grain bullets or larger bullets as heavy as 300 grains.
There are a number of recommended powders to consider. Of course each rifle behaves differently and most people already have some favorite powders in mind, but powders such as IMR 7828, H 7828, IMR 4831, H 4831 perform rather well.
I was tempted to share some load data here, but realize that I may be responsible for someone making a mistake and harming themselves or others.

Click on the image for a closer look. From the the left: Unmodified 8mm Remington Magnum, Necked up to .35, Necked down to .338 (false shoulder), Formed and subsequently loaded .338 Gaillard cartridge.
338 Gaillard cases can be made from the Remington .416, Remington 8mm Magnum, 340 Weatherby, 7mmSTW and the 375 H&H cartridge cases.
Personally, I prefer to base the 338 Gaillard on the 8mm Remington Magnum case, which has become quite popular amongst wildcatters. This is because the 8mm Remington Magnum offers an exceptional sturdy, pressure resistant cartridge case that can be reloaded with relative ease.
There are a few general steps involved in building the 338 Gaillard on the 8mm Remington Magnum.

First, the case should be necked up to 35 caliber. This allows us to create a false shoulder for fire forming the brass.
Second, create a false shoulder by necking the case down a little at a time from 35 to 338. In this step, I removed the firing pin assembly from my Remington bolt and tried to close the bolt on my new case after partially necking the case down in increments. Each time I returned the case to the reloading press and lowered the die a little more. Again I would try to close the bolt on the new case with only a little finger pressure until it finally closed. This creates a perfect 338 neck over a false .35 inch shoulder, which is very helpful when fire forming as it reduces brass flow and prolongs the case life by stretching the case less above the belt.
Third, fire form the cases with a reduced load. I dropped the usual load by 10 percent, and the result was a batch of cases with good shoulders and sharp angles.

Case length. My chamber was measured at 2.8785, and my recommended trim to length is 2.860. By comparison, the 340 Weatherby magnum case is 2.825 in length.

Bullets ranging from 200 - 250 grains are likely the best. I enjoyed testing the 225 grain bullets, but forming 100 in a single range session left me a tiny bit tender.
Why not the 180, or 300 grain bullets? As mentioned earlier, these area also fine choices, but each has slight limitations. Lighter bullets like the 180 or 200 grain may not have the same long range benefits of the 225 or 250 grain bullets, but they are fine for hunting a reasonable ranges, and produce less recoil. I am very tempted to try the 180 grain bullets. I look forward to pushing those through the Chrony.
Let's consider sectional density (Sectional Density or SD is important because it has a significant effect on penetration) Compared to the .308, a 200 grain 308 has a SD of .301, while a 200 grain .338 has a SD of .331. Of course the higher the number the better.

Yes it is. It is very close to the 8.6 x 72mm SDM. It is also similar to the 338-8mm Remington Magnum. In addition, from what I can gather during my research, it may be similar to the .338 Jarrett. (I would like to confirm that if anyone feels like dropping me an email)

Thanks for reading.