I recently examined some MT 30-30 cases hs UMC 30-30. The necks had a cannlure about 1/4" from the mouth leading me to believe they were short range loads and the cases were made for small primers. Were the short range rounds loaded with small primers?
The .30-30 is not a particularly demanding load and could cope easily with a small primer. The primers used in different calibres around this size are more driven by custom and practice and the available space, also the power of the primer is not necessarily governed by its size. It could be a magnum primer.
It doesn’t have to be a reduced load but it may be
U.M.C. loaded 30-30s, specially for Marlin, with small primers. Marlin specified small primers for many of the cartridges labeled for use in their rifles. Marlin 1893 rifles were marked ‘30-30’, not ‘30 WCF’. As for the short range loading using small primers only, I cannot say for sure.
The 30-30 case hardly needs a large rifle primer. In Competition parlance it is known as a 45 grain case, meaning it has an approximate capacity of 45 grains of water. A small rifle primer has enough spark to light any powder charge that you can cram into it.
The U.M.C. 30-30 Short Range cartridges for the Marlin rifle are hardly unique. There are any number of cartridges using the small rifle primer, going back to the very beginning of the cartridge, including full power loads. And a few modern ones too. The 30 American is one. Developed by Benchrest shooters in 1986 it is still being used in it’s original form, and many wildcats as well. It doesn’'t look the part, but the 30-30 is a very accurate cartridge in a proper rifle with good bullets.
Orange–The only two primers U.M.C. used in the .30-30 Win. were the #6 1/2 and the #7. They are easy to tell apart. The 6 1/2 is a small rifle size and is brass. The #7 is large rifle size and is copper. The 6 1/2 was used in all the .30-30 loads (Regular, Miniature and Short Range) until 1910 when they changed to the #7 primer.
The cannelure on the neck was used for both the miniature load (100 gr. Round Nose FMJ bullet) and the short range (117 gr. Lead bullet).
Thanks to all for the info. I knew that ammo with the small primer was made in BP calibres for Marlin but not in smokeless calibres.
BP is interesting in this context. It is slow burning compared to modern powders and usually compressed preventing the flash getting deep into the charge. I would have said that was more justification for a bit stronger primer activity rather than less. But you live and learn.