The decapping pin won't set them off. If you are slow and careful you also won't deform them and can reuse them.
I've fired a few primers before to see how load they were. Like others said, not quite as loud as a firecracker, but defnitely louder than an old school cap gun. I would suggest if you do it to clean the gun afterwards since you will have some of the primer residue in the gun.
What is wrong with the sizing on them? Depending on your sizing die, you could back the decapping pin out / remove it and just size them with the primers installed.
Neck size is .3085". Projectiles full straight thru.
Thanks for everyones help.
Brandan
You might try to neck size a few then and save your self some of the extra work of depriming.
With the "Name Brand" dies, RCBS, Dillon, Redding, even Lyman, you can remove the de cap pin from the de cap rod, and go ahead+re size at will.
As stated before, you can "Push" out your live primers with no problems with a steady pressure placed on your press handle.
I have pushed out primers before+re used them with good luck also..Bill.
Listen before ya load on this one...there's no need to push the primers out. Depending on the design of your dies, it is entirely likely that you can create safe and effective loads without touching those primers.
Like I stated before, this isn't possible with the Lee Collet Neck Sizing Dies. The decapping pin is removable, however if removed, the collet then has nothing to push against when it clamps the neck. I ended up decapping everything and re-sizing with no issues.
Thanks for everyone's help.
Brandan
You didn't state whether the primed brass was commercial or military. If it's military brass it probably has crimped primers in which case I would not try to de-prime them.