Bolt guns and pressures?

kaylorinhi · September 6, 2010, 01:47 PM

The new Stevens is marked .223, not 5.56 NATO, why is that? I understand the pressure increase is something like 6000psi, couldn't a bolt gun handle the +/- 15% increase with ease or there more that I am missing like metalory or quality of finnish or some such?

Mike

HiBC · September 6, 2010, 02:22 PM

This is a off the top of my head answer,no research was done.I suspect if you look at the two pressure levels you will see one was in units of CUP and the other was PSI.
These are both used,and they are different scales.The PSI number will be significantly higher.I could be wrong,but I think if the same units of measure are used,the ratings between 5.56 and .223 are not so different

Dallas Jack · September 6, 2010, 09:00 PM

It's not so much a presure issue as such. A bolt gun has no problem handling that amount of presure.

I think most if not all bolt guns are chambered for the .223 instead of the 5.56 Nato. There is a difference in the chamber between the two and shooting .223 in a 5.56 chamber is supposed to affect accuracy to some degree.

Look to the military pattern semi-auto rifles for the 5.56 Nato chambering. At least that's my understanding of it.
Dallas Jack

JiminTexas · September 7, 2010, 12:00 AM

The differences between the military ammo and commercial ammo is in two areas, headspace and capacity. The external dimensions will be nearly identical, but the military cartridge will have thicker walls, especially at the base of the cartridge which will lead to higher pressures due to the slightly smaller capacity, assuming the same powder charge. The headspace is usually different as well. No, I don't know why, it's just the way that the military works I guess. These differences are the same with 7.62 X 51 Vs .308 Win., 5.56 Nato Vs. .223 and even the venerable .30 Govt. Vs 30-06. The simple solution is to download the military brass a small amount to make it shoot the same as the commercial brass cartridges. How much? For 7.62 Nato I reduce the charge by 1.4 grains. I don't reload pipsqueek bullets, so I don't know, you'll have to experiment a little.

kaylorinhi · September 7, 2010, 07:13 AM

Thanks for the info, i am now better prepared for knowing this. Anybody else's take is greatly appreciated.

Mike

P-990 · September 7, 2010, 04:53 PM

5.56 has a slight larger chamber throat and longer leade. This gives a little more tolerance for mil-spec ammo at the case necks and bullet ogive.

As far as brass capacity, most Lake City 5.56 brass actually has more internal capacity than civilian .223 brass. We Highpower shooters tend to value it because of this attribute (and it's incredibly tough stuff). And you can use Lake City cases in a .223 chamber by simply resizing in a .223 die and proceeding as normal.

Danny45 · September 7, 2010, 05:00 PM

Besides the responses already given, they probably don't want you to shoot milsurp ammo, or cheap steel cased ammo in the gun.

September 6, 2010, 01:47 PM	#1
kaylorinhi Senior Member Join Date: February 13, 2010 Location: The brown eye of america Posts: 463	Bolt guns and pressures? The new Stevens is marked .223, not 5.56 NATO, why is that? I understand the pressure increase is something like 6000psi, couldn't a bolt gun handle the +/- 15% increase with ease or there more that I am missing like metalory or quality of finnish or some such? Mike __________________ Buy your guns by Yardline, Not Looks.

September 7, 2010, 07:13 AM	#5
kaylorinhi Senior Member Join Date: February 13, 2010 Location: The brown eye of america Posts: 463	COOl Thanks for the info, i am now better prepared for knowing this. Anybody else's take is greatly appreciated. Mike __________________ Buy your guns by Yardline, Not Looks.

September 7, 2010, 04:53 PM	#6
P-990 Senior Member Join Date: May 2, 2002 Location: Only1/2WayThere Posts: 1,316	5.56 has a slight larger chamber throat and longer leade. This gives a little more tolerance for mil-spec ammo at the case necks and bullet ogive. As far as brass capacity, most Lake City 5.56 brass actually has more internal capacity than civilian .223 brass. We Highpower shooters tend to value it because of this attribute (and it's incredibly tough stuff). And you can use Lake City cases in a .223 chamber by simply resizing in a .223 die and proceeding as normal. __________________ NRA Master, Highpower Rifle, Across-the-Course NRA Expert, Highpower Rifle, Mid-Range Prone

September 7, 2010, 05:00 PM	#7
Danny45 Senior Member Join Date: September 28, 2000 Location: Tulsa Oklahoma Posts: 434	Besides the responses already given, they probably don't want you to shoot milsurp ammo, or cheap steel cased ammo in the gun. __________________ Danny

September 6, 2010, 02:22 PM	#2
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,286	This is a off the top of my head answer,no research was done.I suspect if you look at the two pressure levels you will see one was in units of CUP and the other was PSI. These are both used,and they are different scales.The PSI number will be significantly higher.I could be wrong,but I think if the same units of measure are used,the ratings between 5.56 and .223 are not so different

September 6, 2010, 09:00 PM	#3
Dallas Jack Senior Member Join Date: February 25, 2005 Location: Dallas Posts: 386	It's not so much a presure issue as such. A bolt gun has no problem handling that amount of presure. I think most if not all bolt guns are chambered for the .223 instead of the 5.56 Nato. There is a difference in the chamber between the two and shooting .223 in a 5.56 chamber is supposed to affect accuracy to some degree. Look to the military pattern semi-auto rifles for the 5.56 Nato chambering. At least that's my understanding of it. Dallas Jack

September 7, 2010, 12:00 AM	#4
JiminTexas Senior Member Join Date: August 25, 2010 Posts: 149	The differences between the military ammo and commercial ammo is in two areas, headspace and capacity. The external dimensions will be nearly identical, but the military cartridge will have thicker walls, especially at the base of the cartridge which will lead to higher pressures due to the slightly smaller capacity, assuming the same powder charge. The headspace is usually different as well. No, I don't know why, it's just the way that the military works I guess. These differences are the same with 7.62 X 51 Vs .308 Win., 5.56 Nato Vs. .223 and even the venerable .30 Govt. Vs 30-06. The simple solution is to download the military brass a small amount to make it shoot the same as the commercial brass cartridges. How much? For 7.62 Nato I reduce the charge by 1.4 grains. I don't reload pipsqueek bullets, so I don't know, you'll have to experiment a little.