.223 to 5.56mm chamber?

[Big Blue]

We've been told for years that it could cause excessive chamber pressures using 5.56mm ammo in a rifle chambered for .223. The .223 specs are for a max. of 50,000 CUP while 5.56mm is 60,000 CUP. My question is this, could I use a reamer to change the chamber and would it then be safe to use military 5.56mm in a Handi originally chambered for the .223?
Thanks,
Don

[revbc]

Don,

I am not an expert on the 223, but it is my understanding they are dimenisonally a little different.  The 5.56 probably being a looser chamber because of auto fire.  H&R says they do not recommend military type ammo in the handi.  I think it is because of hard primers and FTF issues mainly, not necessarily pressure.  The sb2 handi can take substantial pressure and the 223/5.56 case head has a smallish footprint.

However, I am only commenting................I'm sure more knowledgeable voices will chime in.

[Spanky]

I've shot lots and lots... and lots of surplus 5.56 ammo in my 223 Handi's and never had a problem.
 
 
 
Spanky

[mechanic]

Two things you will encounter.  The 5.56 may push the bullet into the rifling, increasing pressure, and the military brass is thicker, further increasing pressure.  You can use the brass to reload for 223, but you have to work up loads as you would any change of brass, etc.
 
Some of the pressure of the military round is used to cycle the action, but on a Handi it just increases breech pressure.  There have been a few cracked receivers on Handi's from using 5.56.
 
I have a friend who damaged a bolt face on a Rem. 770 shooting Wolf ammo in it.
 
Some have done and still do, but for me, I'll stick with factory .223 level loads.
 
Ben

[OSOK]

Michiguns, Ltd. makes the reamer you are talking about. It will take a .223 chamber throat to 5.56, but won't change anything else.

[OR-E-Gun Bill]

As generously throated as the Handi .223's are, would a 5.56 reamer even cut anything?
 

 
Bill

[gendoc]

i jus gotta say... ben an bill's got it go'n on.  so itsa crap-shoot, its yur chamber.. not mine

[jeepmann1948]

Personally I do not shoot the 5.56 in my Handi I save it for my "black guns" if I was ,just to be on the safe side I would rent a 223 Wylde chamber reamer and VERY carefully ream the few thousandths it takes to make it a universal chamber.
Better safe than sorry
George

[knight0334]

As mentioned, you can adjust the chamber/throat to safely fire 5.56 - however, milsurp ammo uses harder primers(because of floating firing pins and bolts slamming shut).  Handi's are already notorious for light hammer strikes with the factory springs.   You'll probably have to swap out the hammer spring to a stiffer unit for reliable ignition.

And, with bottleneck chamber adjustments with the Handi's fixed barrel-to-lug design - it doesn't take much to screw up headspacing.   ...there is no turning the barrel back a little like most bolt guns.   If you screw up you'll either have to fireform your cases to that specific gun with necksizing only after that(unless you get a set of dies custom made for your fired case).  Or rechamber to a larger cartridge.

[Larry L]

The chambering difference between a 5.56 and 223 is the throat dimension. The 5.56 is longer. As far as chamber pressures, the 223 is gauged at a location just in front of the head. The military gauges at the neck. Expect a differential mostly due to the testing locations. Military brass in 5.56 is not heavier than factory brass and internal dimensions are not smaller except what you'd expect to find from lot to lot of any of it.


If you just want, partially neck size a case that came out of the gun. Seat a bullet out past what you normally would. Chamber the round gently. Extract the round. Look for groove marks on the bullet and measure it. That should give you an idea of how deep the throat is on your particular weapon as the barrel grooves have seated the bullet. Probabilities are high that the barrel is chambered for 5.56 or 5.56 Wildey as that's what most 223 marked barrels are actually chambered for.

[cudatruck]

Doesn't someone market a cheap gage to drop in the chamber and measure if its 5.56 or .223 chambered rifle? if not, why? if this issue is such big deal you think a tool would be available?

[mechanic]

Cuda, the firearm will be marked.  Some are marked .223, others marked /223, 5.56.  The biggest problem with a Handi is pressure.  They tell you in the manual not to shoot the mil. spec.   Most black guns will shoot either. 
 
Ben

[Spanky]

I hear alot of talk about the problems with 5.56 in a Handi but... I've shot over 1000 rds. of 5.56 surplus from Sportsmansguide and not had a bit of problems. The primers look perfect and cases extract easily.
 
What if any actual issues or problems has anyone had from running 5.56 in their Handi?? If someone can show me anything I'd certainly like to see it. Someone please show me.
 
Not trying to be a smarta** but if there's a problem I've never seen it.
 
 
 
Spanky

[mechanic]

Spanky,
 
I can't find where I put the photos of the cracked receiver face on the 223, if I can find it I will post it later.
 
Here is a previous link that contains some good info.
 
It's every man's decision about whether to shoot the 5.56 or not.  I'm not going to start an argument over it, but personally I discourage it. I'm not a gunsmith so my advise and about $5.00 will get you a Starbucks.   I shot a bit of mil surp when I got my first .223 without damage, but after seeing damage to a friend's gun that May or May not have been from mil surp, I've sworn off it.
 
http://www.gboreloaded.com/forums/index.php/topic,131527.0.html
 
Ben

[RPRNY]

Not addressing the admittedly important issue of harder 5.56 primers, the Max pressure for the 5.56  (NATO EPVAT 62,000psi) is within SB2 operating pressures and I would very much like to see (as much as Remington's Law Dept would like to not see) any SB2 receivers that were "cracked" using 5.56 ammo. As noted several times above, the key dimensional difference is the longer leade in the 5.56 to allow for bullets such as the XM288 (68 gr Tracer), long M885 steel tungsten Armor Piercing ball or the M262 77gr match grade bullets, all of which require - or at least prefer - the tighter military twist rate of 1:7. Since the H&R twist rates of 1:12 (older) and 1:9 (newer) aren't going to stabilize any of these bullets anyway, your standard 55 - 62 grain bullet is not going to reach the rifling in your Handi, so the higher pressures that MIGHT arise from the thicker brass of the 5.56 (offset by diminished case capacity?) are chimeric.

So, IMHO ream as you may, 5.56 is already within SB2 operating pressures and, unless you intend to shoot bullets that are too long to be stabilized by the Handi twist rates anyway, leade is a non-issue. My opinion. YMMV.

[Swampman]

Doesn't someone market a cheap gage to drop in the chamber and measure if its 5.56 or .223 chambered rifle? if not, why? if this issue is such big deal you think a tool would be available?

It's a non-issue.

[nanuk-O-dah-Nort]

since I recently bought a .223 Superlight, I have been reading up on Milsurp ammo, as we have a dealer who routinely brings in stuff from all over at a decent price.

my conclusions are that the brass dimensions are the same, the chamber is the same, BUT the leade/throat is different.

As RPRNY stated, it is to allow for longer bullets, AND higher pressure, as the Milspec ammo may be loaded to higher pressure than SAAMI and the longer throat/leade allows a higher initial pressure, somewhat.

the important thing to know, is YOUR rifle's throat/leade.   the Handi WILL handle the pressure.  as long as the bullet YOU use is not jammed into the rifling, there should be NO issues at all.

and from what I've read, any ammo that I can Legally buy will fire in a Handi with no issue.

BUT, i will still check it out before pulling the trigger.

this is where a chamber cast is invaluable.