Resizing question

[glennv]

I've been reloading .308 for a couple of bolt rifles over the last couple of years and want to reload a batch for an M1a. I've resized with an RCBS die (full length). I've run a few cases through the chamber and they seem tight. Factory ammo will fall out of the chamber if I tip the muzzle up but the few dummy rounds that I've resized won't. They fit perfectly in my case gauge and the OAL is right where it should be. Is this normal? Any thoughts?

 

[243winxb]

Try a small base die.

 

[MEHavey]

Are these new cases, or range pickup,... or fired
in your other rifles at moderately high pressures ?

If the latter two, a small-base sizing die may be in order to get them back
[1-time reqm't] to SAAMI minimums near the base to fit the tighter M1A

 

[USSR]

Factory ammo will fall out of the chamber if I tip the muzzle up but the few dummy rounds that I've resized won't.

That's because, even with small base dies, you can't size your brass to the dimensions of factory new brass. Still, you may want to use small base dies and see if it helps.

Don

 

[gamestalker]

If FL die adjustment is being done correctly, it sounds like a possible SB die application may be in order. There have been far and few situations in which I've seen an honest to goodness need for SB dies, but they do make them for a reason, this could be one of those times.

Use a sharpies and color the case, then chamber the cartridge several times, then measure where the sharpie has rubbed off, that will be your problem area. If it rubbing off right above the case head where the FL die stops, then a SB die is probably the answer. But SB dies will not address other areas of the brass.

GS

 

[Grumulkin]

You need a small base die.

Even with a small base die, the head to shoulder length may be a little bit too long if the shell holder isn't just right.

 

[Bart B.]

When you are resizing a fired case from that rifle, when the press ram is all the way up pushing the case as far into the die as possible, see if there's a gap between the shell holder and the bottom of the die.

If there is a gap, the die may be set too high and not sizing the case body enough to set the fired case shoulder back a few thousandths. Reset the die in the press a little deeper by turning it in 1/16 turn then try again. The die does not have to touch the shell holder to properly full length size fired cases.

The case headspace (dimension from case head to case shoulder reference diameter) has to be at least .001" less than chamber headspace.

Read post 27 in this thread for a way to easily change the die position in the press very precisely:

http://www.thehighroad.org/showthread.php?p=9983930&posted=1#post9983930

To size fired cases best for your rifle, there may well need to be a tiny gap between the shellholder and the die's bottom. All of my .308 Win chambered rifles have required that.