Rechamber .223 for 5.56?

[pavil58ss]

I've got a Stevens 200 in .223. It would be nice to be able to fire 5.56 in it also, safely.

Would it be feasible to just 'lengthen' the throat/leade to the 5.56 chamber specs? Otherwise the chambers are alike? Correct?

I've some Cerrosafe* but have not made use of it yet.

[sharpshooter]

You will find that the freebore is actually longer than a 5.56. I would do the chamber cast to verify.

[homefrontsniper]

Just shoot 5.56 in it....you will be fine.

[bootsmcguire]

Just shoot 5.56 in it....you will be fine.

Probably, unless you have a 223 chamber with a tight/short free bore. If its too short, and ammo is too warm then bad things start happening.

Do like sharpshooter says and do a chamber cast. If the free bore approaches 5.56 levels then I'd go for it. If it's on the short side then I wouldn't and maybe have it lengthened.

[pavil58ss]

Here's the chamber cast for what it's worth. I put measurements that I took with some vernier calipers. Not sure that it means much really but if I didn't omit anything it looks like 5.56 should work.

I'm thinking the freebore is between the 'shiny' area and the pencil mark. If nothing else I had fun this evening messing with it.

[sharpshooter]

Savage .223 chambers will have a minimum of .100" freebore. From the looks of it , you have more than that. You will be safe.

[Mach2]

Just shoot 5.56 in it....you will be fine.

Ditto

[Ring]

Probably, unless you have a 223 chamber with a tight/short free bore. If its too short, and ammo is too warm then bad things start happening.

Do like sharpshooter says and do a chamber cast. If the free bore approaches 5.56 levels then I'd go for it. If it's on the short side then I wouldn't and maybe have it lengthened.

no, it wont.... most handloads are hotter then factory 556...

[JTCrl]

There are a plethora of discussions on this subject out there, in my opinion this is one of the better ones:

http://www.americanrifleman.org/arti...ats-in-a-name/

Lots of shooters have a love affair with velocity and ammo manufacturers cater to them. In my own case I load for optimum accuracy so my handloads never approach the velocity (pressure) of most factory ammunition.

[Ring]

this 1 is a bit more indepth with actual testing..
http://www.luckygunner.com/labs/5-56-vs-223/

some of the highlights

However, I was surprised about the results I saw. There was no dangerous spike in pressure from firing 5.56mm ammo in a .223 chamber. While pressures were elevated in comparison to one of the 5.56mm barrels, they were slightly below the other 5.56mm barrel.

It’s important to note that most of the .223 chambers I’ve fired 5.56 in didn’t show any signs of excess pressure

Summary: The majority of the experts I consulted over the course of my research did not feel that there was a major difference between .223 and 5.56 chambers in terms of pressure.

[Hotolds442]

Summary: The majority of the experts I consulted over the course of my research did not feel that there was a major difference between .223 and 5.56 chambers in terms of pressure.

I have a hard time taking these so-called "experts" word for this. If they truly were experts, their opinion would not be based on a feeling, but instead, research and testing. Almost anyone can buy pressure testing equipment now, so what field are these "experts" from, Left?
Lucky Gunner is not really where I'd look to find an answer to anything gun related, there are many more reliable sources.

[Ring]

I have a hard time taking these so-called "experts" word for this. If they truly were experts, their opinion would not be based on a feeling, but instead, research and testing. Almost anyone can buy pressure testing equipment now, so what field are these "experts" from, Left?
Lucky Gunner is not really where I'd look to find an answer to anything gun related, there are many more reliable sources.

right, did you miss the part

My greatest concern while researching, experimenting for, and writing this article was whether or not I was putting out accurate information. In order to double check my results, I consulted with over half a dozen industry professionals, all of whom have far more experience in this area than I do. They work for highly respected laboratories, companies, and organizations.
While I do not wish to put words in their mouths, none expressed great concern that I would have a rifle blow up in my face during the course of my experiments. In fact, most said that the actual differences are, in effect, “not a big deal.”

Barnes Bullets tested XM855 and AE223 in their test barrels for us, using the conformal transducer method at the midpoint of the case – the SAAMI method. Their results were slightly different from ours, which can be expected due to the different barrels and the different testing methods, as well as different lots of ammunition, but overall the results were quite similar.