Any data on case life for 300 RUM? Used to get about 5-6 firings out of my 300 WM (no max loads)
Now running just under max for Sierra 190 MK...curious as to life expectancy for this caliber. I know, I know, lots of vairables, but a good ballpark will do.

Thanks for any info,

Jeffrow

What kind of failures are occuring with you .300's after 5 to 6 reloadings? Assuming that it is a split neck, you can expect the same thing from the .300 RUM if loaded in the same way. If it is an incipient head separation, again, you can expect the same thing if the .300 RUM is sized so that it has excessive headspace at each firing.

Some reloaders will make statements based on their own experience like ".308's last a lot longer than .30-06's". This may be true in their two rifles, simple because their '06 die is much tighter in the neck and sizes the neck down excessively, then re-expands it to the proper diameter to accept the .308" bullet. Their .308 Winchester die, on the other hand, may work the neck brass minimally and result in more case life. Or, they may be inadvertantly pushing the shoulder back on one and not on the other, causing head separations.

There's nothing inherently different about the .300 RUM and the .300 Winchester that will cause any difference in case life. There may be a great deal of difference experienced by the individual loader depending on the rifle's chamber and the loader's dies.

Manufacturers have traditionally been very sloppy about chambering belted cases because they assume that they will headspace on the belt (which they do, loosly), so the head-to-shoulder dimension is not important. Presumably, those same manufacturers will be more precise about chambering a rimless cartridge like the .300 RUM. Therefore, the RUM may give the illusion in under these circumstances of better case life.

Appreciate the response...no neck failures (ever). On My .300 WM had primer pockets eventually looen up, was very pleased with bras life.
As for my .300 RUM, am experiencing a strange denting-in of the case just below the shoulder on the main case body. Am using virgin Remington factory brass, no problems on the first go-around, but seems that on second loadings this is where the problem becomes evident...Keep in mind that I am using the same powder, charge load, bullets, primers, sizing setting, etc...the only difference is the fact that the brass has been fired once. Now with this as a given, am I to expect that the 300 RUM is a brass consumer, 1-time fire and chuck it round? Odd if the case as 30-378 Wby et al allow for multiple firings before the heave-ho! Also, my weapon is a premium, non-factory piece, that has an excellent pedigree and no reports of failures as described above, however must add that the other owners do not use brass more than once, so, here I am doing yet another R & D project. Just don't like the idea of 1-time use of a case - who does for that matter. Otherwise this is by far the most accurate .30 I've shot to date, and at 3220 FPS with 190 MK, I'm very pleased with the ranges possible out here in the vastness of West Texas..Just want to reload some cases!

Any input welcome, and can forward images of suspect brass if interested.

Regards,

Jeffrow!

I, personally have only heard of this with severe underloading, not enough pressure to seal at case neck, gasses can enter chamber and dent the case in. A friend bought a 30/378 Weatherby before a lot of data was available, had this happen, he sent cases to weatherby and it was thier explanation.

Tim,

Appreciate the response and confirmation of what we have come to believe is the case (no pun intended).

Have come up with what seems to be a workable remedy:

1) Always "full-length" resize brass (we were only neck sizing and this is when the problem started).
2) Always de-burr flash holes, top-outer edge of neck and throat.
3)Remove all traces of case lube.

We did this and the problem ceased - same performance as new brass, using identical loads!

Keep in mind that we are using the Sierra recommended "accuracy" loads for 190gr MK. BTW, these are really accurate, sub .5 MOA @ 100 yds on all 5-shot groups @ 2313 fps (with a couple of near-1-holers to boot!).

Glad to be back in business!

Thanks again for the input!

Regards,

Jeff

Masher: Why don't you post some pics of those dented cases? It might help solve the mystery.