Fireforming to different caliber

[trickytune]

I have around 50 cases that have been full length sized and new primers fitted for .243 win and I wish to resize them to .260 rem. Should I remove the live primers (not sure I want to do this). Fire the cases outside with just primers and nothing else then resize as usual. Or I have some 243 bullets and dies could I load them up min load and fire them which will fire form them to 260. The rifle is brand new and has never been fired and I do not want to damage the barrel/chamber ever. I am aware that if you put the larger in a smaller bore it very bad but I can't see any issue going the other way. Constructive input please.

 

[Deleted member 46119]

I know what I've done and I'd like to hear what others have done.

You only get away with what you get away with until you don't get away with it anymore.

If it were me and I don't recommend it. Knowing that the primer moves during the firing sequence and should pop out the shell holder with out endangering anything. I would remove the decapping pin from the die and run the 260 expander through the neck. Clean them by hand, check lengths and load.

 

[trickytune]

That may be an option if I have no other ideas

 

[Deleted member 46119]

It's a pretty easy option.

If you have imperial dry neck lube clean up is nothing.

I would not load and shoot an undersized projectile.

Decapping is a waste of material and more risky than running the expander through. Though I've never set off a live primer when decapping.

I'm from California, I just have to say things like I don't recommend it because of all the crazy rejects and lawyers the other states send us.gun)

 

[Mikecr]

I gotta recommend Lapua 260 brass.
But jfseaman's right, you can do it like he describes.

 

[Lefty7mmstw]

I don't recommend shooting undersize bullets to blow out your brass. I've done it a couple of times, both accidentally and on purpose, and it can work well, cause a low pressure situation, or cause a high pressure event that has the possibility of causing major problems. The high pressure is usually associated with shorter cal's going longer and not too small of a bullet, but don't do it either way.


Re-neck with a proper expander ball and go from there.

 

[Leslie Sapp]

Try the Cream of Wheat method. I just reformed some 30-06 that had been necked down to .280 back into 30-06 using this method.

(But I used grits - We don't do Cream of Wheat down here.)

 

[DocDoc]

Use a Sinclair neck expander mandrel to expand the neck up in size. Use a dry lube, so the primer is not damaged.