Just finished assemblying my Bushmaster 16" Dissapator with an A1 upper.  Planned use is for marine (sailing all over the open seas) in self defense.  This weapon must be reliable and I have been the potential victim of marine piracy on three occasions in my life (I am 40).  Anyway, through the great posts on AR15.COM -> Amunition, I have determined that 5.56 M193 Ball is the best ammo for my situation.  All my gear is completely within the law as I must pass through Customs as I travel from the US to the Bahamas to the Dry Tortugas, Nassa, etc.  

I wish for my new Bushy to be the most trustworthy tool and perform perfectly.  I wish to break in this carbine according to the reccomendations of the publication "The M15/AR15 Rifle" a Shooter's and Collector's Guide by Joe Poyer.

After reading his recommendations for break-in, I am starting to think that I could be doing wrong to my weapon system by firering .233 ammo through it when it is really desinged for the 5.56 NATO.  I will also need to purchase ammo from several foreign countries.

Anyway, my question is:  does it cause any loss in accuracy by using both .223 and 5.56 x 45 ammo in the same barrel (especially durring break-in)?  I have acquired a good lot of .223 and am now worried about using it.

Thanks in advanced for your deep knowledge of this awsome weapons system.

Live long and in defense of you and your family...

hmmm i broke in the barrel with about 500 rounds of Fed XM193... I did the clean before shoot thing BM recommends then shot the daylights out of it in one day, cleaned it and now I have to fine tune the sights.
as with what they say with Chrome lined barrels shot the damn thing.
being on the seas get the sealed ammo cans and use some desiccant...lotsa moisture is bad for ammo and I wonder what all that salt air may do to the rifle
Any thoughts guys.

Thanks for the Post R555.  I am sure there is not a correct answer for this situration...  I just wish collect input.  Thanks for the input...

Shoot well and defend yourself and your family...

Thank you Troy.

Thanks for your reply...

Drive fast and slide around the turns...

I have been an avid sailor for approaching 16 years including atlantic and pacific passages and extensive single handing.  I have on two occasions been forced to brandish arms to defend my oceangoing yawl from potential aggressors who would not respond to hails or appeared intent to board without permission.  On both of those occasions it was a 16" Bushmaster with optics that I had on hand.  On both occasions simply producing the "evil black rifle" defused the situation instantly.  The kneeling position in the cockpit is quite effective for cover as well.

In my experience you have made an ideal selection.  The Bushmaster milspec finish resists corrosion well.  Critical for seafaring weapons.  AR15 style weapons are intimidating and easily recognized at distance by most individuals regardless of background.  I usually don't believe in producing a weapon for the express purpose of deterrence.  Still, in this case I am happy to have not had to open fire on anyone on the high seas.  The other advantage is that you can store the weapon as separated upper and lower to meet the legal guidelines in some waters of not having assembled weapons and still have the weapon assembled and functional in less than 15 seconds if needed.  (Thank you Bushmaster push-pins).  Make sure you check local laws carefully but usually you are ok if it is stowed on your vessel.  Technically, you are importing the weapon if you make anchor in the coastal waters of a sovereign.  Watch out for Canadian waters too.  Also, if boarded by USCG it is best to declare your weapon and note that it is for self defense.

For ammo, the best, most serious ammo for your purposes is probably M193 milspec ammo.  You will obviously want SEALED ammo.  Stay away from surplus.  I recommend new Lake City but suggest you buy a small sample first and submerge a few random rounds for 48 hours before pulling to see if the powder holds up.  I seem to remember that some lots had bad sealant.

Break in your Bushmaster by taking it down to the range and shooting 400-500 rounds of any kind without cleaning in any way in between.

Shoot 5.56 or .223, it matters not with Bushmasters.  M193 (particularly Lake City) is going to be the best "cheap" ammo with sealant for your purposes.  It is also quite deadly inside of 150 meters out of a 16" weapon.  Using the improved battlesight zero (zero at 50 yards/meters) you shouldn't have to correct at all out to 200 yards.  About right for encounters at sea.  Optics are highly recommended.  I use a "scopecoat" on mine to keep them salt water free when stowed.

Additionally, when singlehanding or with a light crew I often will put out a few pieces of carpet with 1.5" roofing tacks punched through pointing upwards on deck or in the cockpit at night.  Unwelcome borders will announce themselves quite nicely when they encounter it in the dark, even in the middle of the night while trying to be stealthy since most of them are barefoot or wearing only light shoes.

Sail safe.

Edited to add:

Also, never announce your impending departure on radio.  Pirates have radios too and leaving means you just stocked up on provisions.

Scott please tell more about the pirates and your dealings with them. Thanks

Glockdog

Airborne!!

.223 Remington is .224" actually.

.223 is NOT the same as 5.56 as far as chambers go.  You can find the details in the FAQ.  www.ammo-oracle.com.

And if chambers was the question you might be right.  But .223 and 5.56mm IS the same bullet/round.  

Your referenced source:


"Dimensionally, 5.56 and .223 ammo are identical, though military 5.56 ammo is typically loaded to higher pressures and velocities than commercial ammo and may, in guns with extremely tight "match" .223 chambers, be unsafe to fire."