Just started loading for PRS style matches this year.  Been reloading for years but more for massive quantity vs. precision.

I'm loading my Prime .260 Remington brass, Norma I believe, but I need more brass and want to get virgin.

Looks like I can buy .243 Norma up to $.30 cheaper per case than .260.

Good idea or bad idea to get the .243 and neck up?

Edited to add my key question is how will it affect accuracy compared to my existing Prime once fired?  Will loads need to be drastically different in cases to achieve same velocity?

Thanks!

I necked up a bunch of 243 to 260 and have fired them about 6 times so far and it has been just great.  I tried to neck down some 308 to 260 and had a very hard time.  The necks still look great on the 243/20 brass.

necking up reduces neck wall thickness (which reduces strength and life).

It really shouldn't impact it a whole lot, especially if you anneal.  I'd personally just use brass that is already the correct caliber.  Makes life a lot easier.  I wouldn't count on mixing it in to your existing stock of brass and having it shoot exactly the same either.

That’s kinda what I was thinking.  Lot to lot variability matters so makes sense that would too maybe more so.

False economy when necking up stuff that already exists.

Buy Lapua and never look back!  The case life with Lapua with pay back many times over!
Anneal the brass
Use Bushing Dies
Controlled Bump FL sizing
Do not run the snot out of the brass.

I personally have 20+ reloads on Lapua 308 Brass and the primer pockets are still snug.
Just have to take care of the brass!

I neck 243 to 7-08 for my gas gun all the time. I can get 8 loads before w/o a problem after about 10 I get loose pockets and toss it.

Upside you really don't have to trim for quite a few loads lol. Just make sure depending on the finished case length you can end up with a carbon ring in the chamber that can cause problems with some ammo. I make sure to clean my chamber after every match.