Interesting question. The Lyman #311291 is a round nosed bullet that was designed in 1905. It's been used in the 30-30 ever since. No flat on the nose. Lyman did come out with #31141, now cataloged as #311041 which is supposed to be #311291 with a flat nose. I've been shooting cast bullets for almost 50 years, and #311291 has been my mainstay in all my 30 caliber rifles, including the 30-30. I've never had a problem with detonation in my model 94's with that bullet, and I load them to full power specs in 30-30. I've never heard of a detonation in the magazine with that bullet either, but that does not mean it has never happened.
Currently, I am playing with the RCBS #30-180-FN, a bullet that has a flat nose and weighs 190 gr. in my alloy. Why so heavy a bullet in the 30-30? I once read an article about the .303 Savage which pushed a 190 gr. bullet to 1950 FPS. Supposedly, it was considered a better killer on deer and elk than the 30-30, due to the heavier bullet. The .303 Savage rifles in decent condition are hard to come by, and ammo is even more difficult to get now that it has been discontinued. The simple solution is to load the 30-30 as if it were a .303 Savage. Sam Fadala, in his book, WINCHESTER'S 30-30, MODEL 94, he says he would buy .303 Savage ammo to get the 190 gr. Silvertip bullets to use in his 30-30 as Winchester never made the bullets available as components. I have five boxes of .303 Savage ammo on hand, but considering that they'll bring $40 or more a box at gun shows, I don't plan on breaking them down for the bullets. Those bullets are a very blunt round nose style, FWIW.
I would imagine that any cast bullet with a meplat larger than the primer should work without problem. You'll just have to go with what you are comfortable with.
Paul B.

Thanks Paul and Pete
I should have mentioned I plan to use a Woodleigh with the nose including part of the jacket turned back to give a 1/4" meplat so there will be copper jacket at the edge. I'm getting built a 50-110 and plan to use a 525grn jacketed bullet

The answer to your question is "it depends". The size of the meplat, the recoil of the load, the hardness of the bullet, and the angle of the bullet to the primer in front all come into play. Some rifles (Marlin 1895 45-70)have the last round loaded at a slight angle with the ones in front in the tube. This can put the sharp edge of a meplat right on the primer in front. A heavy recoiling load and hard alloy will set off the rounds in the magazine, even though the bullets have flat meplats.

Like Paul, I have used the RN 311291 in tubular magazine 30-30s for years with full snort loads and nary a problem. The 30-30 just doesn't generate enough recoil to allow the blunt RN bullet to set off the primer.

The home test is to take a primer case (no powder or primer) and place it in a vice. Take your bullet of choice and place it on the primer. Smak the base of the bullet real hard with a hammer. It the primer pops, you might ought not to use that bullet in a tubular magazine.

Fellows,

I have always wondered if filing a sharp pointed bullet a little on the nose to make it flat enough for a tube magazine was safe, even a jkt one? BM