bullet seating plug

[wild willy]

How important is it that the seating plug matches the bullet profile? Talking handgun.Is it better that it seats off the end of the bullet or the sides?I know RCBS makes specific ones for Speer bullets.Whats wrong with using a flat one for RNFP or SWC bullets Just curious I know they they seldom match perfectly.

 

[Charlie98]

The generic plugs that come with generic dies are a guess at bullet profiles. A flat nose plug will mash the round tip of a FMJ bullet if the seating and crimping resistance is high (using the seater as a crimp, which is one of the many reasons I seat and crimp separately.) Conversely, if you seat a FP bullet with a RN plug, you may 'crown' or deform the FP bullet in the same circumstances. If you are seating a bullet on top of a compressed powder charge, or have a case with a lot of resistance, this will magnify the problem.

Does it matter? In general handgun ammos, probably very little unless it significantly deforms the shape of the bullet. Rifle ammos is a different story.

 

[edwardware]

How important is it that the seating plug matches the bullet profile?

Completely unimportant. . . except for:
1) Concentricity: the seater should center the top og the bullet to line up with the die centering the case neck.
2) Deformation: the seater should not distort the bullet enough to matter.

For pistol, I've never seen a bullet that the Lee concave plug didn't center well. I do notice a mark on the bullet, but there's no way it matters to RN/FP/WC profiles.

For rifle, I have had to relieve and hone a few seaters to avoid mashing or excessively ringing long fragile HP bullets.

 

[Texas10mm]

There's one specific seating plug that I like for handguns. It's a SWC seating plug that indexes off the shoulder and not the nose.

I can load any SWC bullet in 45 ACP and have them end up where my pistols like them....and NEVER have to adjust the seating die.

Beyond that a RN and flat plug works great.

 

[H&R Glock]

Will it make a difference if the bullet is not aligned with the mouth of the case when it enters the seating die?

 

[9mmepiphany]

Talking handgun.Is it better that it seats off the end of the bullet or the sides?

If you mean the ogive when you posted "sides", then yes that is "better" as it will generally result in more consistent OAL

 

[Chuck R.]

As the other's said, it depends on your accuracy requirements and the bullets.

Speer GDs for instance can easily be deformed while seating due to their construction. RCBS makes specific seaters for them by weight. I've also got a couple sets of dies that have specific seater plugs for VLD bullets.

 

[AJC1]

This one time in band camp..... I seated 115 rmr 9mm mpr with an expander mandrel and it worked just fine. I felt dumb when I figured it out but that is an extreme example.

For precision rifle I believe it to be very important.