View Full Version : Interarms .223 Mark X serial 2062

April 18, 2012, 01:18 PM
I will be receiving this weapon very soon and had a question that I can't seem to find the answer to.

My Dad is telling me that the Mark x is Barreled to handle 5.56 nato rounds!?

As I understand it .223 are 55g and the 5.56 nato's are 62g.

My research also lead me to many different discussions about the rounds being slightly different?

Does anyone have any info available to them confirming what round if any the .223 weapon is capable of firing other then.223?:confused:





Jim Watson
April 18, 2012, 01:29 PM
A search on the make and model indicates that it has a 12" twist.
That is the Vietnam era standard for 55 gr M193 5.56 or commercial .223 varmint loads with bullets 45-55 grains.
It would not work well for M855 62 gr or heavy bullet .223.

Bud Helms
April 18, 2012, 03:26 PM
Bullet weights vary, but there is a slight difference in the dimensions of the cartridges.

Here was a good discussion on the difference: http://thefiringline.com/forums/showthread.php?t=376962&highlight=223+vs+56

I had some success using the search feature on this one. It doesn't always work so good. Search for 5.56 vs .223 or change them around: .223 vs 5.56. I got 33 hits (33 different threads). I searched for titles only.

April 18, 2012, 06:20 PM
You will never have a problem with either round in that rifle. 5.56 and 223 are both offered in many weights, from 35 gr. up to 80 gr. If this rifle is a 12 twist it will probably be more accurate with bullets in the 55 gr and under weights. It might shoot some that are slightly heavier ok, you'll just have to shoot it with different weights and see.

Does anyone have any info available to them confirming what round if any the .223 weapon is capable of firing other then.223?

The 2 are the same round. The military calls it 5.56, civilains call it 223. The military does load their ammo a tad bit hotter and uses looser chamber tolerences in their rifles to promote better reliability. For all practical purposes they are the same. While some get all upset and try to claim they are 2 different rounds no one has ever provided any evidence of a problem although 90% of shooters have no idea of the supposed difference and use them interchangeably. At worst some semi-auto rifles may not function with 100% reliability.

April 18, 2012, 11:18 PM
You will never have a problem with either round in that rifle.

That's what my dad said...Im just trying to understand why he said it? Does that make sense? Sorry I know I am asking a lot of questions but I keep getting conflicting info on the subject. I will be receiving my new rifle hopefully this Saturday and Dad said he is sending 500 5.56Nato rounds also.
I want to take it to the range as soon as I get it but I really want to be sure It will not have a major fubar incident with those rounds.:o

Thanks again to all that have replied as I will have many more questions soon about my HP C9:D

April 19, 2012, 05:06 PM
Scroll down to 5.56 NATO vs. .223 Remington for the difference explained:


If the rifle is chambered in NATO, as your Dad indicates (it will be stamped on the barrel) either can be used without concern.

I am inclined to agree with the above, that it's not really a big deal- but there can be significant pressure differences. I have shot 5.56 ammo from a .223 Rem 700, I just don't make a habit out of it.

Do a search, both on this forum and online, there is enough on this to put you to sleep for a week.

Good luck with the rifle, I hadn't seen a Mauser conversion to 5.56 before. I've always seen them done in larger hunting calibers.

April 20, 2012, 01:04 AM
Thats a YZ/Serb produced "Mini-Mauser" that has been imported under various labels for quite a few years, Remington even did some recently.
They are not military Mausers, but scaled down commercial actions for .223, maybe the Hornet, and I think recently the 7.62x39.

Mine wants to shoot, but I need to bed it. Oddly, I get fair groups with REm 69 gr match HP ammo. But its regular diet is 55 gr whatever.

April 27, 2012, 01:11 AM
I have shot BOTH 5.56 and .223 in every gun I have owned chambered for either and NEVER had a problem, that includes a Howa 1500,two Stevens 200's, Weatherby Vangaurd(same as Howa) Remington 700, several AR15's, and a handfull of Mini14's. Mabe I am living on the edge, but I doubt it......

That Mini-Mauser is a cool gun I have two friends that have custom .222's built on that action and they both love them.

April 27, 2012, 08:17 AM
The only problem I've ran into is shooting 5.56 out of my Handi rifle. I have an older ejector barrel on my Ultra Varmint and it will fail to eject about 50% of the time. Once reloaded or running factory .223 I never have an ejection failure. All my AR rifles have been labeled 5.56, and I've never had a problem running it in my bolt actions labeled .223.

May 17, 2012, 03:03 PM
Thank You to all that have replied I truly do appreciate you all taking the time to post up your thoughts and opinions based on your experiences..:)