Tips For Seating Flat Bottomed Rifle Bullets?

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That seater die sounds pretty awesome! But in the meantime tonight I tried running the shell plate up real close to the die, put the bullet up in the die and dropped it down on the case. Very laborious but it seemed to work okay.

Although two of the rounds I made looked a little "off". It was barely enough to notice but it seemed like the two rounds were angled, just ever so slightly. If I took a picture of it I guarantee nobody could see it. I even rolled them on the bench looking for wobble on the bullet and I couldn't see any. I don't know if I'm just psyching myself out over it or if they are actually off.
 
As an aside, I made a 9MM expander plug for a Lee expander die body earlier this evening, and I made it a two step expander. I tested it out and it worked quite well. Sending it to a friend tomorrow.

And your friend greatly appreciates it.:)

Don
 
Another vote for Lyman M die.

That seater die sounds pretty awesome!

Hornady seater dies are nice, and I have one for each of my rifle calibers. But I bought them before trying the M die. The M die is "better," and it makes the drop-down guide on a seating die fairly redundant. You will be able to sit the bullet straight up in the neck, in most instances.

The M die is better because it has additional benefits. It also allows the bullets to start into the neck without scraping. It allows you to expand with less effort, no neck stretching/distorting, and using no neck lube.

The downside of the M die is that it can take an extra step, if you use a SS. I prime while "M"ing, so it doesn't bother me.

make sure you are Chamfering the inside of the case mouth. Then just hold the bullet in the correct position until it enters the seating die..
This doesn't always work with "regular" seating dies. Even after the tip enters the seating die, a short and blunt bullet can tilt so far that it doesn't center on the seating stem. Then the crooked bullet just destroys the case neck. If it ain't broke, don't fix it. So if you don't need extra stuff, good for you!
 
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It sounds like a Lyman M die would eliminate the need to guide the bullet into the seater, but wouldn't it add the requirement for at least a taper crimp after (or during) seating to smooth out the case mouth?
No. With a Lee Universal Flare die, you might have to crimp. That's cuz unless all your brass is trimmed to exactly the same length, a Universal Flare die will put varying amounts of flare on the brass.

The M die does a stepped flare, sized exactly for that one caliber. No matter how long your brass, it sizes the end of the mouth only ~1 mic over the size of the bullet. This does not have to be removed. One mic is nothing. If you pick up any two different headstamps of brass, you can find many times that difference in the thickness of the neck.
 
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Flat based bullets and boat tailed bullets, go in the same. Chamfer and deburr the case. When seating, hold the bullet on top of the case with your fingers. Easy easy easy. I don't have small hands, and my fingers work just fine.

If your going to load cast bullets then get an expander die, but if your only loading jacketed bullets, don't waste your time with a expander or m die. Just useless work, and you can ruin brass quick if not careful.
 
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