Are 5.56 mm x 45 cartridges safe to reload in .223?

Edchef

Well-Known Member
Good Morning All
I recently picked up 100+ used 5.56 x 45 cartridges (S and B Headstamped) on my local range
I realise that the spec. for these and .223 Remington are not quite the same and there seems to be conflicting info. on the internet as to whether they are safe to reload and fire in a .223 or not
Should I just dump them or try a few checking for signs of pressure as usual?
What do you all think?
Ed
 
No you you should immediately send them to me ,foc , for examination / testing , I will eventually give a report as to their edification.

:norty: :old:
 
While the external case dimensions are very similar, the .223 Remington and 5.56x45mm differ in both maximum pressure and chamber shape. The maximum and mean pressures for some varieties of the 5.56 mm (different cartridge designations have different standards) exceed the SAAMI maximum for the .223 Remington, and the methods for measuring pressures differ between NATO and SAAMI.[SUP][2][/SUP] The 5.56 mm chamber specification has also changed since its adoption, as the current military loading (NATO SS-109 or US M855) uses longer, heavier bullets than the original loading. This has resulted in a lengthening of the throat in the 5.56 mm chamber. Thus, while .223 Remington ammunition can be safely fired in a 5.56 mm chambered gun, firing 5.56 mm ammunition in a .223 Remington chamber may produce pressures in excess of even the 5.56 mm specifications due to the shorter throat


Above applies to Ammunition not brass


reload with care and take usual precautions should be fine
 
Ok Gentlemen - Thank You all
It has been suggested to me that I start with a load 10% below normal and work upwards - checking as always!

Thank you again - off to the reloading room (all right the spare room! )
Ed
 
Ed , am interested in doing the same with my .223 Howa , have read so much about not reloading 5.56 cases and firing them in a .223 but it is interesting to see that guys have had no probs with them , would be keen to try a hundred or so rounds . Let me know how yours go , all the best Joe .
 
I've read horror stories about putting 5.56 through a .223, but I've put many through mine with no ill effects.
 
I've read horror stories about putting 5.56 through a .223, but I've put many through mine with no ill effects.

your mileage may vary...basically its down to how the throat is cut in your particular rifle.
if its a short throated .223 and you use 5.56mm 109 type with the bullet jammed into the lands...you might just get a surprise of a bad kind though it may only be hard extraction due to over pressure...
if however you have a longer (or perhaps eroded) throat then you may not experience pressure issues at all and all is well.

there is .223 wylde chambering for this kind of situation too ....

Also you do get rifles chambered for 5.56 but proofed .223rem so ...
 
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