Shooting new rifle for 1st time and...

[Bushwack44]

...its chambered 556/223 (Mossberg MVP Predator) . Should I first shoot a handful of 223 to break in the barrel (as its less 'potent') or it doesn't really matter which caliber goes first?

[TMB 1]

Doesn't really matter.

[Divernhunter]

Does not matter.
If you do not understand they are both the same CABIBER. They shoot the same DIAMETER bullets.
Just do not shoot all copper bullets AFTER shooting regular jacketed bullets. You need to super clean the barrel when switching from regular to all copper.

[Bushwack44]

I know they are the same CALIBER and DIAMETER. But 556 has a bit more oomph. Was curious if it mattered.

Question has been answered. Thanks guys.,

Does not matter.
If you do not understand they are both the same CABIBER. They shoot the same DIAMETER bullets.
Just do not shoot all copper bullets AFTER shooting regular jacketed bullets. You need to super clean the barrel when switching from regular to all copper.

[golfish]

Enjoy you new rifle..

Please post up a range report

[Bushwack44]

Enjoy you new rifle..

Please post up a range report

I'm just going to go to Angeles and shoot steel.

[Gene1986]

I would break in the new rifle the proper way as I PERSONALLY have seen a difference in breaking a rifle in and accuracy.

[JMP]

It isn't a high precision rifle and it sounds like you are looking at factory ammo, I'd just start out with a few various ammos and see what the gun shoots best with. With that said, you will generally be able to buy ammo of better accuracy results with .223 over 5.56.

[killshot44]

It's a1/9 button-rifled chrome moly barrel with a longer throat for 5.56. Rather than spend time/$ on needless break-in, do as JMP suggests and buy 3-6 different types of ammo from 55 to 69 grains and fire ten shot groups to see what it likes.

The last factory .223 I had loved the cheap PPC 55gr, may you be so lucky.

[User76]

My MVP loves the Wolf Gold .223 and disliked the M855/XM193 variety.

[ElvenSoul]

You have to break in the mags.

I use the same 4 mags for my MVP

[alabamacoastie]

Don't let anyone try to make you feel bad for asking this question. I remember shooting my first AR for the first time. I had the same question. I ended up shooting .223 through it because it was cheaper at the time.

Then, i built an AR308 and had the same question about .308/7.62. I spent a lot of money on a fancy premium barrel and wanted to make sure i broke it in right. I wondered if i should shoot .308 through it first and then "move up" to 7.62 rounds. I ended up buying some ammo labeled .308 and some more ammo labeled 7.62. I still haven't had a chance to get that rifle out to the range...

[Oceanbob]

No matter.....

Good choice. A really good bolt gun....I like that it runs AR mags.

Are you planning on a Scope?

Range report and photos are required.

[JackEllis]

You need to super clean the barrel when switching from regular to all copper.

Wish I'd known that a month ago. Can you explain why in terms an idiot (me) can understand? Is it because copper will stick in the grooves of the rifling if they aren't clean?

[B Strong]

...its chambered 556/223 (Mossberg MVP Predator) . Should I first shoot a handful of 223 to break in the barrel (as its less 'potent') or it doesn't really matter which caliber goes first?

The only thing you need to do is check the bore for obstructions before shooting.

"Barrel Break In" is a myth.

In some narrow categories like BPCR rifles there may be a benefit from polishing the bore, but I'm not convinced that even that gives enough benefit to make the work worthwhile.