Several powders performed well behind lightweight .243 bullets, including Winchester 760, Hodgdon's Varget and RL 15 by Alliant.

When Winchester introduced the .243 Winchester in 1955, the company made a winning decision to market it primarily as a deer and antelope caliber. Model 70 barrels chambered for .243 had a 1-in-10-inch twist to properly stabilize the 100-grain bullets that Winchester had designed for deer-size game and loaded in its factory ammo.

Remington introduced its .244 (now the 6mm Remington) the same year. The .244 had a slightly larger powder capacity, which translated into slightly higher muzzle velocity than the .243. Remington saw its new caliber primarily as a varmint caliber, so the company used a slower, 1-in-12-inch twist. This worked fine with the 70- to 90-grain bullets featured in Remington factory ammo but did not properly stabilize 100-grain and heavier bullets that were considered suitable for larger game.

As it turned out, hunters agreed with Winchester's concept, and the .243 became a popular caliber even though the .244 was its ballistic superior on paper. The .244 was eventually reincarnated as the 6mm Remington in rifles with 1-in-10 twist barrels. But the damage was done, and the 6mm never achieved the .243's popularity. Today, only a handful of manufacturers chamber rifles in 6mm Remington.

Because the .243's success is based on its usefulness on deer and antelope, it's easy to overlook the fact that it is also an excellent, wind-bucking varmint-getter.

Now, the term "varmint" covers a lot of ground--from pocket gophers to coyotes--but the .243 has the versatility to do it all. With 80- and 85-grain factory loads, the .243 is somewhat faster than a .223 Remington with a 55-grain bullet. Of course, the 85-grain .243 bullet has a higher sectional density than the 55-grain .223 bullet, so the bigger bullet has about the same velocity at 300 yards as the .223 has at 200.

But where the .243 begins to shine as a varminter is with ultralightweight bullets that have become available in the past few years. Two manufacturers, Nosler and Sierra, now offer .243-caliber polymer-tipped 55-grain bullets. And Hornady has a similar 58-grain projectile.

Several manuals now list loads for the .243 that nudge past 4,000 fps with these bullets. Oddly, published ballistic coefficients for the 55-grain .243 bullets are roughly the same as for almost all 55-grain .224 bullets, so the .243 shooting a 55-grain bullet at 4,000 fps shoots a trifle flatter than either the .22-250 or the .220 Swift. Although the .243 burns a good bit more powder than any .224 short of the .220 Swift, it is still a pleasant-to-shoot, low-recoil proposition. That, of course, is a subjective judgment. I recently read an article by an avid benchrest competitor who found that 20 rounds fired from a bench rest in a sporter-weight .243 was "punishing." Those who agree with him should probably take up needlepoint and give up shooting.

I used a Savage M116FLSS left-handed bolt action to test handloads. The 22-inch barrel and receiver are stainless steel fitted into a composite graphite/fiberglass stock. My scope was a Burris Signature 2.5-10X.

I wired the Savage for the Oehler Model 43 Personal Ballistic Laboratory via a strain gauge bonded to the barrel over the chamber. The Model 43 allows you to simultaneously obtain muzzle velocity and chamber pressure along with other interior ballistic and pressure data as well as exterior data including time of flight, velocity at the target, ballistic coefficient and standard deviation on all values.

The first step was to collect baseline pressure and velocity data using factory Winchester Super-X 80-grain PSPs. This load averaged 67,100 psi (M43) along with an average muzzle velocity of 3,198 fps.

SUITABLE POWDERS
Alliant	Rl 15, RL 19
Hodgdon	BI-C2, H335, Varget, H4895, H414
IMR	IMR 4895, IMR 4350
Vihta Vuori	N135, N150, N550, N160
Winchester	WW 760

This was significantly lower than published factory muzzle velocity for this cartridge/bullet combination, but published ballistic data for the .243 is obtained with a 24-inch barrel. So, the lower velocity can be largely attributed to the 22-inch barrel on the Savage (although several other factors may also contribute to the disparity). I worked up handloads using the average factory chamber pressure obtained as the upper allowable limit. Using this limitation, I did not achieve the velocities listed in various loading manuals, undoubtedly for the reasons mentioned earlier. Even so, the velocities obtained are well into the "potent" range.

Besides three ultralightweight bullets, I tried out the 70-grain Sierra BlitzKing and the Barnes 85-grain XLT. The Sierra, in particular, performed well, giving good velocities and excellent accuracy with several powders. Hodgdon's Varget, Winchester 760 and Alliant's RL 15 performed exceptionally well in several bullet weights, but all the powders I tried worked pretty well. Without exception, peak pressures increased at a steady and predictable rate; powder charges were increased incrementally. This is the sign of a well-designed and docile cartridge that will perform with consistency and top accuracy.

There is one caveat to keep in mind when you are assembling .243 varmint loads. Factory .243 barrels must be chambered and throated to accommodate 100-grain and larger bullets, which means it is nearly impossible to seat lightweight bullets out far enough to touch the rifling lands.

In fact, you'll need to adjust your seating die to seat lightweight bullets significantly deeper than bullets in the 100-grain range. Otherwise, you won't obtain sufficient neck tension to hold the bullet securely in the field. However, my test rifle still delivered sub-MOA accuracy even with bullets seated .020 of an inch off the lands, so it doesn't seem worth worrying about.

.243 WINCHESTER VARMINT LOADS
Bullet	Powder	Primer	Case	Starting Load (gr.)	Maximum Load (gr.)	Muzzle Velocity (fps)	Notes
55-gr. Sierra BlitzKing	RL 15	Fed210M	W-W	39.8	43.8	3,761
55-gr. Nosler B-Tip	WW760	Fed210M	W-W	44.2	48.2	3,842
55-gr. Nosler B-Tip	Varget	Fed210M	W-W	39.2	43.2	3,802	Accurate
58-gr. Hornady V-Max	H4895	Fed210M	W-W	38.5	42.5	3,745
58-gr. Hornady V-Max	H414	Fed210M	W-W	43.5	47.5	3,747
78-gr. Sierra BlitzKing	H4895	Fed210M	W-W	35.2	39.2	3,369
70-gr. Sierra BlitzKing	RL 15	Fed210M	W-W	36.8	40.8	3,423	Very Accurate
70-gr. Sierra BlitzKing	IMR4350	Fed210M	W-W	41.9	45.9	3,342
70-gr. Sierra BlitzKing	WW 760	Fed210M	W-W	41.3	45.3	3,483	Accurate
85-gr. Barnes XLT	Varget	Fed210M	W-W	43.0	47.0	3,051
85-gr. Barnes XLT	IMR4350	Fed210M	W-W	39.7	43.7	3,062

The .243 is powerful enough to be effective on deer-size game, but it's not so powerful that it'll leave you bruised and sore after a long day of shooting prairie dogs.

WARNING: The loads shown here are safe only in the guns for which they were developed. Neither the author nor Primedia assumes any liability for accidents or injury resulting from the use or misuse of this data.