358 BELLM LOAD Data
Developed by Don Shearer, Littleton, CO.
Designed especially for TC Contenders
Data developed in a TC Contender S-14, 1-14" twist rate, 8 groove factory barrel, rechambered by Mike Bellm.
Maximum Chamber Dimensions
Cases: Reformed R-P .444 Marlin
Max. Trim Length: 2.200" Bullets:
Hornady and Nosler
Primers: Fed. 210
About the Data, and My Comments About the Cartridge.:
First and foremost, it is understood that both Mike Bellm and Don Shearer disclaim any liability that may result from the use of this data. You use it at your own risk. Since there are variables from gun to gun that can effect the results you obtain, it is imperative that you always start low and work up. Do not ever use any loading data like a cook book and just dump in the top load and hope for the best. Always, if there is any hint of hard opening after firing or difficult extraction, back loads off.
f you have not done so, please read about Don's testing regimen in the .308 Bellm Data section, link in the left hand menu bar.
The .35 caliber barrels made by TC have had some misfortunes that make them good buys and popular candidates for rechambering to .358 Bellm.
A number of shooters have had problems with misfires in the .35 Rem factory barrels, and although these barrels have been among the most accurate that TC has produced, .35 Rem. barrels often sell used at modest prices, making them excellent candidates for rechambering to .358 Bellm.
357 Herrett barrels, while usually excellent barrels, receive limited attention from only those willing to cut cases back and fireform. Reloading dies have been commonly available, but do usually cost more, which is another drawback. Plus, case life of .30/30 brass is viewed by some as being too short for the work expended making the cases.
The excellent .357 Rem. Maximum was dealt a dirty blow from the first day TC chambered for this round using a .4" long forcing cone ahead of the chamber instead of a throat. This cone goes from the .380" chamber diameter down to bore diameter in a cone over the distance of .4" and gives absolutely no positive support to the shanks of bullets. Thus they enter the rifling at random angles and give accuracy far below the potential of this round. Results from this very accurate cartridge are undermined by TC's choice of chamber and throat design and this has done tremendous damage to interest in the .357 Maximum. Thus, here is another example of a .35 cal. factory barrel that can often be picked up used for a reasonable price.
The reason I have detailed this scenario is because at first I could not understand why so many people were sending in .35 cal. barrels for rechambering to .358 Bellm when the overall interest in .35 cal. Contender barrels appeared to be quite low. Dealers had commented time and again that it was harder to make the .35s "go away" than it was other calibers. Thus the prices were somewhat depressed. But when a barrel can be bought reasonably, one can well afford to put some money into redoing it.
This seems to be the basis for the unexpected popularity of the .358 Bellm.
The TC factory 8 equal land and groove barrels tend to run .001" to .002" undersize, so after market barrels with true .358" groove diameters and conventional narrower rifling may permit higher velocities than posted below.
On this continent, from a Contender there is little need for more power than the .358 Bellm delivers. Granted, there are larger cartridges that are quite popular, but much of the popularity is based more on successful promotion than need. Where the .308 Bellm may fall a little short for elk, for example, the .358 Bellm fills the niche between the .308 Bellm and .444 Marlin rather well, and as do the other "Triad" cartridges, the .358 Bellm accomplishes this with common dies, and only the .358 Win FL die set is needed..... nothing more.
Reloading Dies for .358 Bellm: Selection of brand of dies has been narrowed down to Lyman as the best choice since they usually size closest to new brass dimensions. RCBS dies are next best, but are usually priced higher.
Hornady and Lee dies are too short inside for the full length .444 Marlin case and will not work. While Redding makes excellent dies, they, too, will be pretty pricey, but my objection to Redding is more in regard to their not sizing the web areas small enough to suit me. They usually require cutting a chamber diameter larger at the web than I choose to cut.
So unless you will also use a .444 Marlin size die to size the case webs, I would not recommend Redding. (Note that if you want to do the two die thing leaving case webs fire formed as explained in the "advanced" method on the Triad page, you can also use the smaller proportioned Lyman .358 Win size die in tandem with the Redding dies to accomplish the same thing for less money.) Powder Selection. After thorough testing, Don Shearer established that H322 was clearly the best powder for .358 Bellm of all the powders tested. 4895 came in second best. You may find other combinations you like better, but the following is proven data you will do quite well with.
Comments Regarding Bullets. For some reason, the test barrel did not like 220 gr. Speer bullets which was a disappointment since we had rather high hopes for this bullet. The Hornady bullets are generally excellent game bullets that also give good accuracy.
And as will be noted in the other sets of "Triad" data, Hornady is Don Shearer's bullet of choice for general use, but "your mileage may vary." For long range big game work, the Nosler 225 gr. Ballistic Tip is outstanding. Don also conducted extensive expansion tests with the Nosler bullet and finds it a very good choice.
358 Bellm Data
.358" Hornady 180 gr. Flat Base Spire Point. # 3505
Refer to Hornady ballistics tables for energy and trajectory figures.
.358" Hornady 200 gr. Flat Base Spire Point. # 3510.
(The Hornady 200 gr. round nose bullet, #3515 may be substituted. Start low and work up.)
Refer to Hornady ballistics tables for energy and trajectory figures.
*Note: Start the usual 10% low and work up.
