I am looking for reloading spec's on my thompson contender 357 herrett barrel it is a 30/30 necked up to a 357 bullet,I cannot find spec's to modify 30/30 case or powder spec's can someone help me get back on the firing line?

This may help a little>>>
.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.

Some load data>>>
http://accuratearms.com/data/guide/handgun/standard_data/357%20Herret%20T-C%20data%20page%20106.pdf

Jules,
Very good explanation of the way to form 357 Herrett. I'd have little to add, even though I vary a little in method. I would add that Imperial sizing die wax is very good stuff for the forming process (being carful to keep it off the location of the new shoulder, oil dents are ugly), and to remember to remove the expander button stem for rough forming operations.
Another point I would make apart from the forming info., is that though the 35 Rem. works well in the Contender and I have taken several head of whitetail with it, it doesn't have the "I like the looks of it" aspect that the 357 Herrett does. I like a rimmed cartridge in a single shot rifle or pistol. I sold my 35 Remington barrel and bought a 357 Herrett barrel simply because I like the Herrett in either 30 cal. or 35 cal. and I have sort of a little "collection" of made-from-30/30 cartridges, and barrels to fit them. My 357 Herrett barrel is 14". I have a 10" 30 Herrett that I was so impressed with that I bought a 20" Bullberry carbine barrel in 30 Herrett too.
I like also the 6mm Bullberry Imp. and the 219Donaldsn Wasp.(I have a carbine VV Wasp and a BF falling block pistol in 219 Wasp. That makes me a total of 5 Contenders in four cartridges who are loaded from formed cases that started out as 30-30.
If you add the Martini's in 219 Zipper and 219 Zipper Imp., that's 6 cartridges that I form from the 30-30.
TD

Jules, Nice job! I'm a big Bob Milek fan and you hit the nail on the head when explaining "the best in a 10" barrel". Both calibers are great.
Can't count the deer and Antelope my 30 Herrett has taken.

Ross Seyfreid recommended some sizing lube made by Rooster Labs for forming and said it was excellent for the purpose.

Anybody familiar with this slop and where to get it?

A funny bit of trivia is that Milek and Herrett used VO-5 hair cream to form cases for the 30 Herrett in the early experiments.

Regards

[ 12-16-2002, 03:28: Message edited by: Headstamp ]