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Case-Forming Top Contender Hunting Loads

T/C shooters can improve handgun performance by making their own potent field rounds for five powerful cartridges.

The single-shot Thompson/Center Conten-
der handles a variety of loads suitable for
pronghorn antelope, deer, and even small
bears.

Some of the most popular hunting cartridges for the Contender handgun are also some of the most labor-intensive to handload properly, particularly when forming their cases. This is particularly true of five well-known rounds for the Contender handgun: the .357 Herrett, the 7mm TCU, and three cartridges developed by J. D. Jones, the .300 Whisper, the .309 JDJ, and .375 JDJ. Each of these cartridges requires unique case-forming methods, and the problems and solutions encountered in working these rounds can apply to a variety of case-forming applications for handguns and rifles. Here’s what you need to know about forming brass for each of these powerful cartridges:

.357 Herrett
After Steve Herrett’s and Bob Milek’s success with the .30 Herrett, they decided that a larger, more powerful load was needed for hunting. In those days 10-inch barrels were most common in the Contender, so this was a big consideration in the load’s development.

The .357 Herrett was designed from the parent .30-30 case. The mouth was opened to .35 caliber and the shoulder pushed back to 1.360 inches with a 30-degree angle. The taper is blown out of the body for a much straighter case.

This cartridge has been dropped from the Contender lineup in favor of the factory-loaded .35 Remington. Though the .35 Remington is a fine round in a 14-inch barrel, it is not even chambered in the 10-inch tube. The .357 Herrett is much better in the 10-inch length. The .357 Herrett is one of the finest hunting rounds ever developed for the 10-inch Contender, and it’s a shame that Thompson Center no longer offers it.

Likely the largest reason for its demise was difficulty in forming the cases. With the introduction of 14-inch and longer barrels, the .35 Remington took over because of the availability of factory ammo and the ease of reloading. However, the .357 Herrett remains one of the classic and best handgun-hunting calibers, particularly in the much handier 10-inch barrel length. For deer and black bear at woods ranges, it is a great choice. While not often thought of as a varmint caliber, there are a bunch of woodchucks and a few coyotes who would debate that, if they were around.

Even though it is a rimmed cartridge and the parent .30-30 Winchester does headspace on the rim, the .357 Herrett headspaces on the shoulder, not the rim. It is important that the case be formed so that the shoulder supports it on the very first firing the fire-forming load). If the case is allowed to headspace on the rim, it will result in the case stretching ahead of the web.

This is usually noticeable as a bright ring or even a crack on the case just ahead of the web. In extreme cases or if the case is used again, separation will often result. This can damage both the gun and the shooter.

To ensure that the case headspaces on the shoulder, the sizing die should be set so the base is 1/4 inch above the shell holder when the press ram is raised all the way to the top. Run a case through the die and trim it to 1.750 inches. Because this requires shortening the case by 0.29 inches—and that’s a lot of turning on a hand-cranked trimmer—the Power Trim Pro Trimmer from RCBS will speed up the job.

After chamfering the mouth, try the case in the gun. It should not chamber all the way, and you should not be able to close the action. Now screw down the die in 1/8-turn increments, running the lubricated case in each time and trying it in the gun. The object is to size the case until the gun will just close with no interference from the case. Take care not to go beyond that point.

The old thinking was that the gun should close with just a little force so that the shoulder was jammed against the chamber. The problem: If this operation was not done correctly, the Contender would misfire. Instead, the shoulder should be pushed back until the gun can close without interference from the case. The danger here is that the shoulder can be in the correct position, or it can be pushed back too far, there is no way to know for sure. Either method requires that careful attention be paid to the process. I prefer to have a very slight interference from the case when closing the Contender. If this interference is minimal and the gun is closed with a sharp snap, there is usually no problem. Also, I accept the possibility of a misfire and never use the first fire-forming load for hunting.

No matter how you decide to adjust the sizing die, once you find this place, lock the die and size the remaining cases. I used a feeler gauge to measure the space between a fully raised shell holder and the bottom of the die and saved that number for future reference. Or you can carefully measure the distance from the top of the die to the top of the locking ring. This can help to speed up the process the next time you need to form a batch of cases. Because this dimension can vary with different presses and dies, it is important that you check your own setup.

After sizing your remaining cases they must be trimmed to length, and the case mouths chamfered inside and out. Here I use the RCBS Trim Mate Case Prep Center to speed up the job. Then I clean lubricant off the brass by tumbling it.

Fire-forming loads should not exceed 90 percent of the final loads. The Bullseye-Cream of Wheat method doesn’t work as well here, probably because the diameter of the neck is large in relation to the body, so fire-forming with bullets is necessary.

After fire-forming you must adjust the die so it does not contact the shoulder. In theory you can simply leave the setting you used for forming the brass, but to be safe and to extend case life I prefer to back the die off a little bit, usually about 0.040 inches. You can check this by putting some machinist blue on the case (it also works to simply color the case with a felt marker) then lube the case and run it into the die. If the die is contacting the shoulder, it will be apparent.

Always use magnum primers and powder charges that are near maximum for the best results in the .357 Herrett. Check for case lengthening after each firing, particularly the first, and trim as necessary.

7MM TCU
TCU stands for Thompson Center-Ugalde. Wes Ugalde developed the cartridge; Thompson Center chambered the guns and legitimized the load. Based on a necked-up .223 Remington with the taper and shoulder altered, this popular cartridge was introduced in 1979 at the height of the silhouette competition boom. The 7mm TCU offered good performance on steel with manageable recoil. The relatively fast 1:9 twist would stabilize heavy bullets, and it proved dependable on rams.

While the 7mm TCU performed admirably on the silhouette course (in the #3 Nosler Reloading Manual David Bradshaw called it the most winning caliber in IHMSA history), hunters have also discovered it. The 7mm TCU will work well on varmints, predators, antelope, and on small deer at close range.

The case forming process for the 7mm TCU is fairly simple. Run the .223 case into a full-length resizing die equipped with a tapered expander button designed to expand the neck from 0.22 inch to .284 inch. The datum line remains the same, and the case will headspace on the shoulder. The case is then loaded with about a 90-percent charge and is fire-formed to create the sharp 40-degree shoulder and to “blow out” the taper in the body. These fire-form loads are accurate and are fine for light varminting. For serious hunting, you will want to milk all you can out of the round, so fully formed cases should be used when preparing your loads.

Another alternative is to load the sized and primed .223 Remington case with a charge of 5 or 6 grains of Alliant Bullseye powder topped with enough Cream of Wheat to fill the case to the bottom of the neck. Then pack the neck with a plug of toilet paper.

By firing these cases, enough pressure is created to fire-form the brass to the final 7mm TCU dimensions while saving on the cost of bullets and powder used for other fire-forming. Be sure to clean the barrel of the gun well before using it again. Also, don’t underestimate the power of these loads, they can cause serious injury or even death at close range, so be careful where you point the gun when you fire.

After fire-forming it is best to only neck-size 7mm TCU cases for future loading. Many shooters will mark their cases so they are oriented in the chamber the same each time they are fired. This not only helps accuracy, but will greatly extend case life.

When loading, take care with the 7mm TCU cases because of their delicate shoulders. It is easy to collapse or bulge the shoulder when seating a bullet or full-length sizing the case. If you are full-length resizing, make certain that the die is not touching the shoulder. It is easy to push this small shoulder back during the sizing process. This will result in misfires and in case separations. Make certain that the neck is clean and well lubricated inside and out before any sizing operation, as any excessive drag on the expander button can alter the shoulder. The mouth must be well chamfered before attempting to seat a bullet to allow the bullet to enter without catching or binding.

Check the case length before each loading and trim when needed. The trim length is 1.750 inches. If allowed to grow too long, the case will contact the end of the chamber, possibly collapsing the shoulder and certainly creating high pressures and poor accuracy. This condition can also cause misfires in Contenders.

Military cases can be used, but they are not the best choice. The heavier brass doesn’t fire-form as well, and the decreased case capacity will reduce velocity and energy levels with safe loads. Take care with load data because many loads that were safely developed in commercial brass will spike pressures to unsafe levels in military cases. Usually the first indication of this is sticky extraction of the fired case. It doesn’t take much more pressure before you will start expanding the primer pockets, ruining the case and creating a dangerous situation.

.300 Whisper
J. D. Jones developed this caliber, and it was originally conceived as a subsonic sniper round for a rifle, hence the name Whisper. It didn’t take long for the round to emerge as a great handgun choice. My Whisper barrel is one of J. D.’s 10-inch models, but Thompson Center also offers this chambering in both 10- and 14-inch barrels. Cor-Bon offers factory ammo in 125- and 220-grain loads. However. their cases still carry the original .221 Fireball headstamp, and with no factory brass headstamped as .300 Whisper, we must still consider it to be a wildcat, but one that is offered as a loaded round. In any event, most Whisper shooters will likely be making their own cases.

The .300 Whisper will give nearly the same ballistics as a factory-loaded .30-30, particularly when using the 10-inch barrel length. Muzzle flash and recoil are much less than in the .30-30, however, and in most cases accuracy is better. The heavy 200-grain and 220-grain bullets work well on steel targets, toppling rams well. They do not break the sound barrier; thus, are not subject to transonic effects on accuracy. The 220-grain Sierra load from Cor-Bon starts out at 1,040 fps at the muzzle, and because of its high ballistic coefficient, loses only about 70 fps over the 200-meter trip to the rams.

For hunting game up to deer size, this caliber is surprisingly effective. Here the 125-grain Nosler Ballistic Tip has emerged as the bullet of choice, although many hunters prefer the heavier 150-grain Ballistic Tip.

The parent .221 Fireball cases are available only from Remington. Since the XP-100 handgun is now discontinued and no current factory firearm is now being offered in this cartridge, brass can be hard to find.

J. D. designed this case to be completely formed with one pass of the sizing die. However, the failure rate can be a high, with split necks not uncommon. In my Hornady three-die set, there is one expander designed expressly for making the brass, but the failure rate is high with a lot of split necks. Instead, I use the full-length resizing die that is supplied with a tapered expander button. It gives me better results.

Allan Jones, who edits the Speer #12 Reloading Manual, prefers the Bullseye/Cream of Wheat method, using 5 grains of Bullseye powder followed by ten grains of Cream of Wheat. He simply fills his powder measure with Cream of Wheat and doles it out like powder, followed by a toilet-paper plug. He says he has a zero case-failure rate with this method. Though this is true, my limited testing shows the extra work offsets the failure rate, so stick with the forming dies and accept the losses. To minimize these losses, it helps to chamfer the case mouths before sizing. Also, be certain that the inside of the case neck is well lubricated before expanding the neck.

With the small case capacity in relation to bullet weight, pressures can escalate very quickly, so extreme caution must be maintained while working up loads. The first indication of pressure creeping too high is sticky extraction. Again, high pressures tend to expand the primer pocket, ruining the case for future use. Use caution with published load data: I have found some to be optimistic. In one case the starting loads expanded the primer pockets.

.309 JDJ
This may well be the best handgun-hunting caliber for deer and similarly-sized game ever developed. It is superbly accurate, flat shooting, and hits like Mike Tyson used to hit.

Like J. D.’s other handcannons, the .309 uses the .444 Marlin as a parent case. These cases are only available from Remington, but because Marlin continues to chamber the cartridge, supplies will probably remain strong.

When stepping up in caliber, as with the previous cartridge, there is more forgiveness in the condition of the parent case. Because we are necking down here, it is important that the new case not have any dents or defects in the case mouth. If you try to size the case with a dent in it, a wrinkle is likely to appear in the neck, ruining the case. To iron the dents out of the new cases, run them over a neck-expander die, either for the .444 Marlin or use a .44 magnum that is backed off the shell holder. Take care not to run them far enough up the expander to bell the mouth. Then chamfer the case mouth inside and out.

Forming the .309 JDJ requires two sets of dies. You will need the .309 JDJ of course, but you also need a .308 Winchester sizing die. If you simply attempt to run the brass into a .309 JDJ sizing die, the case will collapse and be ruined. The shoulder angle is too abrupt for the brass to handle the transition. Instead, you must run the brass into a .308 Winchester die. Back the die off the shell holder. Adjust the die until you can just close the Contender’s action with a sharp snap. Make sure that the shoulder is contacting the front of the chamber; this rimmed case must headspace on the shoulder and not the rim.

You can then load a 90-percent charge and fire-form the cases. J. D. tells me that he has achieved minute-of-angle accuracy with the fire-forming loads. I prefer to use the Cream of Wheat method to save on bullets. Because of the larger case capacity, I used Alliant Unique powder instead of Bullseye. My charge is 12 grains of powder topped with enough Cream of Wheat to fill the case to the bottom of the neck. The charge is topped with a toilet-paper plug wedged into the neck.

After forming I like to resquare the mouth on a trimmer and rechamfer, but J. D., who has made thousands of cases, says he thinks this step is unnecessary.

.375 JDJ
This is the big daddy of Contender cartridges. It has been used to stop charging elephants, but it is quite at home in the whitetail woods. It is amazingly accurate, and with a compensated barrel, it is not too brutal to shoot. Again, the parent case is the .444 Marlin and all the preceding information about straightening out the neck before forming the case applies. That is the single most important thing you can do to ensure minimal case loss. After that run the brass through the sizing die, clean, and load it. That’s it. J. D. said he designed the .375 for simplicity.

Also With This Article
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Click here to view "Pet Loads."


-By Bryce M. Towsley




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