Seating flat base .223 bullets?


something vague
May 12, 2009, 10:15 AM
I have recently been reloading for .223 Ruger M77 and have only had boat tail style bullets. I picked some Sierra 53gr. matchkings up at the shop and just realized that they are all flatbase style. I neck sized some brass and just for fun tried to see how the bullet would sit on the case as if I was getting ready to seat it. Needless to say the bullet will not sit on top of the case like a boat tail will and don't know how I am gonna get the bullet to reach my RCBS seater with out falling over. What can I do to remedy this issue as I can't be the only one who has run into this? I chamfer all my cases and can't see chamfering them too much more without making a sharp edge. My RCBS die is the basic style die so there is nothing supporting the bullet once inside the die until it reaches the seater stem.

I have been contemplating getting the Forster Bench Seater die lately for a more accurate seating procedure as I haven't been real happy with the RCBS. Will the Forster die support the bullet as soon as it enter the die or will this still be an issue?

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May 12, 2009, 11:17 AM
Your RCBS seating die will work just fine.

Set the bullet on top of the case and guide it into the die as you slowly lower the handle.

It will straighten itself as it gets to the shoulder portion of the die and enters the neck area.
The bullet point will be in the seating stem & centered before any pressure is applied to seat it.

Been doing it for near 50 years in a lot of calibers, in a lot of RCBS dies, so I can assure you it will work just fine.


May 12, 2009, 11:22 AM
Almost all seating dies are designed to align the bullet and case and to seat the bullet correctly. Assuming you have chamfered you case, just hold the bullet in place until it enters your seating. The brass case is maleable enough to allow the your flat based bullet to seat in the case. Not to worry. :)

Doug b
May 12, 2009, 01:15 PM
Something vague,you might try Lee's dead length seat die to improve your procedure.It adjusts down to the shell holder giving your fingers a little more room to work and guides the bullet quite well.There is no crimp collar so the bullet and casing are fully contained and aligned during the seating operation.I can do flat base bullets for 22 hornet without fear of wrinkling a case mouth.Bullet runout is in the .002" to.003" range with once fired neck sized brass.

something vague
May 13, 2009, 08:50 AM
Thanks for the replies, I haven't actually tried seating the flat base bullets yet but was just playing around with it and couldn't get the bullet to stand up very well on its own like a boat-tail will. Guess I'll have to play with a little more as I know people use flatbase bullets all the time without issue. We'll see, just been spoiled with all the boat-tails I have had.

dagger dog
May 13, 2009, 10:29 AM
The RCBS competition seating die has a window cut into the side of the die and a floating guide that holds the bullet in alignment with the case until it enters the case mouth.

I have used one in .308 Win, it works well, but I have found no advantage over the regular seating die or over the Lee dead length seating die.

I have always held the bullet until the case is moved into the die with the bullet sitting on the top then I tap the top of the die between my thumb and index finger rapidly as I move the case up to where I feel the bullet start into the case. My theory is the vibration from the tapping allows the bullet to "center" before it enters the case.

Of course all this is based on the assumption you are trying to load as accurate ammo as possible and have PLENTY OF TIME.

Such practice is in vain if you are loading blasting fodder for your MINI 14!:D

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