Why factory ammo for barrel break in?

[LongWalker]

I've got a new 300 WSM build in the works and have already assembled all the components dies, projectiles, etc (save 215M primers) and started looking for factory ammo for barrel break in when it eventually shows up.

Started looking for factory ammo and as expected not a ton of choices available and not cheap. To boot the Norma bond strike which is the most plentiful doesn't get glowing reviews for accuracy.

That got me thinking why not just use quality components I already have a just do a middle of the road load for the first 25 or so and then start load development.

I'm thinking and hoping I'm just stuck behind the curve and most folks already use this option. I use the same style load to fire form brass after barrel break in already so there can't be some magic to factory that makes it the best choice for a new rifles first shots.

Or is there......

 

[HSmithTX]

I have never used factory ammo to break in an barrel, why spend the money when you don't need to? You should be able to find some Hornady Interlok or something like that for 25 cents each-ish and load those. I use the lowest cost cup and core bullets I can find. Depending on the barrel and how accurate you are trying to get you may need to shoot 100 or more to get the barrel fully broken in, only your chronograph and cleaning patches can tell you when it's done. Plus you will have 100 pieces of brass fire formed in your chamber to start the real load development. Win win in my book.

 

[LongWalker]

Exactly what I was thinking and don't know why it hasn't registered sooner.

 

[LongWalker]

That actually leads me to a second question. With a magnum cartridge (300 WSM specifically) not running slow burning powders like H-1000, RL-26, N-560, Retumbo, etc, do you need a magnum primer for the best performance? I'll be running the Berger 205s and lighter and likely RL-23, RL-16 and maybe RL-19 so will I benefit from the extra umph of the magnum primer. It will also be a shorter barrel (21") and I literally just got Quickload today so if that's a resource I should work I'll try that too.

 

[GLTaylor]

No need to use magnum primers either. Just something to light your powder at moderate velocity.
Besides - mag primers are too hard to find lately (for me at least). You are not developing loads. You don't start that until you've burnished your barrel and gone through "speed up"

 

[LongWalker]

Got it. Once I start full power load development is it better to use them than not? I've got a good supply of 205&210Ms so I think I could trade at some point if it comes to that and the 215 will make a difference.

 

[Jbumblebee]

Way back when, before you were probably born, factory ammo was fairly inexpensive. I've used it to break in rifles and kept the fire-formed brass to reload.

These days scrounging for components seems to be the way to go.

Good luck in your endeavor and enjoy your new build.

 

[birddog 68]

Way back when, before you were probably born, factory ammo was fairly inexpensive. I've used it to break in rifles and kept the fire-formed brass to reload.

This is the reason I have used factory ammo for break in but it's definitely not the good old days of cheap ammo.

 

[GLTaylor]

Longwalker,
The old rule of thimb was use mag primers at 70gr charge and above. The case geometry of the new short mags has shown that this is not always the case today.
In older, longer (taller) cases this is still pretty typical. (Like Win Mags) In the newer short/fat cases, you can sometimes pressure out prematurely. Try both types of primers. You may find you can burn more powder/get more speed with a more gradual burn/pressure curve. Your rifle and chrony will tell you what's best

 

[LongWalker]

Thank you sir. That is excellent information and advice.

 

[QuietTexan]

I buy Factory Seconds brand from Midway for fireforming cases and breaking in barrels.

I've liked some of these seconds so much that I've bought more of them later on.

 

[morgaj1]

The only reason I have used factory ammo to break in a barrel is to save primers.

 

[dok7mm]

I wouldn't use factory ammo unless I was going to use the factory brass for my reloading, the exception being barrel break-in only.

I always find my quality brass, powders, dies, etc prior to building the rifle. Makes things run smoothly. Best quality brass is usually cheaper in the long run for primer pockets lasting. JMO

 

[FEENIX]

I've got a new 300 WSM build in the works and have already assembled all the components dies, projectiles, etc (save 215M primers) and started looking for factory ammo for barrel break in when it eventually shows up.

Started looking for factory ammo and as expected not a ton of choices available and not cheap. To boot the Norma bond strike which is the most plentiful doesn't get glowing reviews for accuracy.

That got me thinking why not just use quality components I already have a just do a middle of the road load for the first 25 or so and then start load development.

I'm thinking and hoping I'm just stuck behind the curve and most folks already use this option. I use the same style load to fire form brass after barrel break in already so there can't be some magic to factory that makes it the best choice for a new rifles first shots.

Or is there......

Go for it if you would rather use hand loads instead of factory ammo. I use factory ammo to break in my barrel except for my wildcats. I do load development after fireforming brass off the chamber.