I have a super 14 223 barrel, older G1 frame.  Can I safely shoot 5.56 in it.  Any owners shooting the 5.56 regularly in the 223 barrel?  I understand the difference in the two cartridges, just thinking about extra pressures, stretching the frame, etc.

WIth a small case base like 223, frame stretch is of little concern. You'll get sticky extraction and poor accuracy before you need to worry about frame stretch. This is assuming you're reloading...

With my super 14, I found, the upper middle part of 223 load data got me best accuracy. Especially with lighter 45-55gr bullets.

If you're looking to shoot factory 5.56, don't expect anything more than mediocre accuracy...

Edit:
Something too keep in mind..

That barrel has a 223 chamber. I've not seen any issues shooting loads up to 5.56 pressures with mine except accuracy dropped off. Having said this, not all chambers are cut exactly the same.
If you get hard unlocking, sticky extraction or any smearing on the case base stop shooting 5.56 pressure loads...

You'll get sticky cases and eventually bend the extractor/ejector if you use 5.56mm ammo in a Contender.

It's designed for accuracy, not power and if you take the time to work up a load you'll find that a 14" Super Contender in .223 is capable of better than 1/2 MOA accuracy.

No, even if you had a 5.56mm chambered barrel, the TC Contender and Encore are NOT designed to handle 5.56mm chamber pressures.

http://www.luckygunner.com/labs/5-56-vs-223/

An interesting read.

I'M WRONG!  I did some more research and it turns out that the determining factor whether or not a cartridge is safe in the contender is bolt trust.  Bolt thrust is a number derived by multiplying the SAAMI maximum chamber pressure by the square of the cartridge's base. Here's a link to an Excel spreadsheet for determining bolt thrust. http://r.duckduckgo.com/l/?kh=-1&uddg=http%3A%2F%2Fwww.ar15barrels.com%2Fdata%2Fthrust.xls

The bolt thrust for a 5.56x45 using 62000 psi as the chamber pressure is 7139 psi.  The hottest cartridge ever chambered for the contender by TC was the 375 JDJ.  Using Quickload's max chamber pressure of 51000 psi, its bolt thrust is 8844 psi, well above the 5.56x45.

E. Arthur Brown even advertises custom barrels for both the contender and the encore in 5.56x45 Nato.  http://www.eabco.com/cntndr01.html

We need our own sub-group....... Trying to talk myself out of getting a 357 Max pistol barrel.......

Picked up 400rnds of new brass at Miday for $17.95 per 100rnds.

I use .223 Rem for lightweight bullets.  Most 5.56mm guns have barrel twists for heavier bullets for better down range performance on larger stuff.

CD

super 14, 357max is awesome knocking down steel, get one!

I've got 600rds of starline 357max brass, should last my life time and then some...

I used to shoot a 375 JDJ Contender...that 556 isn't stretching anything.  Was the 223 load measured in CUP or PSI?  Military load is measured in PSI. Two completely different pressure measurement systems and they do no correlate whatsoever.

I would have ZERO concerns shooting 556 in a Contender.

Can't help you I have 2 Encores; a handgun and a rifle. I've killed at least a half dozen deer during the time HPR's weren't legal. With a 180gr they never went far. Love the Max