Can 308 win and .223 be resized to NATO??

shortandlong said:
just wondering ? I want to know for future use
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They are the same cases.

Dimensionally 5.56 = .223 and 7.62 = .308 as far as the cases. So YES, you can size them to NATO Spec, because they already are.

Now if you mean "Can I reload .223 Rem to 5.56 NATO specs?" Then the answer is no. The case is thinner etc. .308 Win can be reloaded as 7.62x 51 NATO as they are the same.

The difference comes into play when you take chamber pressure into account. 5.56x45mm NATO is a higher pressure cartridge than .223 Rem even though the case is the same size.

Read the following:

http://www.winchester.com/lawenforcement/news/newsview.aspx?storyid=11

.223 Rem VS 5.56mm

Paul Nowak
5/4/2001
.223 Rem VS 5.56mm

There are a lot of questions about these two cartridges. Many people think they are identical - merely different designations for commercial and military. The truth is that, although somewhat similar, they are not the same and you should know the differences before buying either cartridge.

* The cartridge casings for both calibers have basically the same length and exterior dimensions.
* The 5.56 round, loaded to Military Specification, typically has higher velocity and chamber pressure than the .223 Rem.
* The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader.
* The 5.56mm and .223 Rem chambers are nearly identical. The difference is in the "Leade". Leade is defined as the portion of the barrel directly in front of the chamber where the rifling has been conically removed to allow room for the seated bullet. It is also more commonly known as the throat. Leade in a .223 Rem chamber is usually .085". In a 5.56mm chamber the leade is typically .162", or almost twice as much as in the 223 Rem chamber.
* You can fire .223 Rem cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity over firing the .223 round in the chamber with the shorter leade it was designed for.
* Problems may occur when firing the higher-pressure 5.56mm cartridge in a .223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads and gun functioning issues.
* The 5.56mm military cartridge fired in a .223 Rem chamber is considered by SAAMI (Small Arm and Ammunition Manufacturers Institute) to be an unsafe ammunition combination.

Before buying either of these two types of ammunition, always check your gun to find what caliber it is chambered for, then buy the appropriate ammunition. Most 5.56mm rounds made have full metal jacket bullets. Performance bullets - soft points, hollow points, Ballistic Silvertips, etc. - are loaded in .223 Rem cartridges. Firing a .223 Rem cartridge in a 5.56mm-chambered gun is safe and merely gives you slightly reduced velocity and accuracy. However we do not recommend, nor does SAAMI recommend, firing a 5.56mm cartridge in a gun chambered for the .223 Rem as the shorter leade can cause pressure-related problems.

Winchester Law Enforcement Ammunition East Alton Illinois

And then read this:

http://www.smellysmleshooters.net/ammopressure.htm

By Jim Bullock

I have pressure tested thousands of rounds of ammo in many different calibers both professionally (years ago) and more recently using the facilities of the Canadian Gov't (Explosives Branch) and Expro (maker of IMR powder).

While I don't like sweeping statements, in 308/7.62 I have found that although the specifications have very similar maximum acceptable pressures, the military ammo is usually "hotter".

Commercial ammo tends to run a round 55,000 psi while I have seen some lots of military running around 60,000 psi. (Same pressure gun, observed in the same pressure testing project.)

Ammo specifications can be miss-leading. Military ammo is usually quoted using the CUP system whereas commercial ammo is quoted in psi. The actual pressure maximums are about the same, but the numbers are about 5,000 units apart. This can create the illusion that the military is lower pressure.

The military know what rifles the ammo will be used in and have a guarantee that the rifles will be in good shape. Commercial companies worry about lawsuits. There are rifles in poor condition, miss-matched bolts, unsuitable actions, etc. The last 50 feet per second will cost about 5,000 psi. As a commercial loader I would trade off 50 fps for the safety of 5,000 less pressure, any time. Although commercial ammo can be loaded to 60,000 psi the companies I have discussed this with tell me they don't like to go beyond 57,000 and 55,000 is what they prefer.

The military brass is heavier than commercial brass. I load 308 in commercial brass that weighs 157 grains. I load 7.62 in brass that weighs 195 grains. (I happen to have a large quantity of both types). Since the outside dimensions are the same, we know the internal capacity of the 7.62 case is less because of an extra 38 grains of brass. The powder capacity is very different and the pressure/velocity results of the two are so different I have to treat them as quite different calibers. The light brass can use a larger powder charge and obtain higher velocity at the same peak pressure. The peak pressure of a 308 and a 3006 are the same. The difference is powder capacity. More powder translates to more energy and more velocity. To a lesser extent, the same thing is true of 308 vs. 7.62

Commercial ammo seldom exploits the larger case capacity. In practice I find the military ammo loaded fairly "hot" and commercial ammo is less than max pressure.

Pressure being equal, the military brass offers a significant safety factor. Some actions have chambers with less head support than others, so a thick head is important.

When loading for 303 British the same thing is true about brass weight. Military brass is heavier. Segregate your brass, military vs. commercial and use 2 grains less powder in the military. If you load 3 to 5 grains less than the max powder charge shown in the book you will find the brass lasts much longer. 20 reloads instead of 3 to 5. Just neck size the first quarter inch of the neck, if it is to be shot again in the same rifle.

The suggestion about shooting over a chronograph is an interesting one. If the bullet weight is the same, higher velocity equates to higher pressure, but only if the brass is the same. As I have explained, 308 and 7.62 brass is not the same.

The Hornady Light Magnum ammo I have shot in 308 (both production and experimental) offers significantly higher velocity (around 200 fps) for ordinary pressures (around 55,000 psi). This is accomplished by using a very large charge of compressed slow ball powder. They stuff a 3006 load of slow ball powder into a 308 case. Don't try this at home. You can't do it.

In conclusion, commercial ammo probably has lower pressure than military. Military is safe if the rifle is in good shape. Hornady Light Magnum has unremarkable pressure and I would not hesitate to use it any rifle in good shape.

Handloading and down loading 100 to 200 fps is much easier on the rifle, the brass and the shoulder and is still perfectly fine for punching paper out to 600 yards (about 500 yards farther than is usually required.)
 
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The text above covers many areas. Now the exceptions. 7.62NATO from the time of the M14 had a LOWER pressure both overal as well as gas volume to account for the needs of the M14 cycling system. Compared to 308 'bolt action' ammo.

Have not shot any modern 7.62NATO ammo so can't say. However, fairly recent load data I have seen show the NATO to be loaded to a lower overal pressure and velocity then the 308Win. This was done in part by using lower amounts of faster powder.

The 223/5.56 is a little more stable. The main difference is in the leade of the chambers BUT the chamber in an individual rifle can vary alot.

Been playing with a Stevens in 223. The leade on it is very much like the 5.56, maybe even longer. Shooting 5.56 ammo in this chamber would pose no risk to rifle or shooter.

Although there are rules of thumb, each rifle is a system onto itself and care must be taken to load for its particular needs.

Remember that there are over a dozen chamber designs for the 308Win, let alone what happens as reamers wear and are reground. So even loading for what is stamped on the pipe needs care.

Start low and work up....

Jerry
 
shortandlong said:
have you done it ?
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Yes

shortandlong said:
are there dies for 5.56 and 223?
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Just in case you missed the first time, they are the same.
If you don't believe me, pick up some loading manuals. There is a reason Hornady and Sierra have separate load data for AR-15s and 5.56 NATO.

shortandlong said:
there seems to also be a problem with casing thickness
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There is no problem with case thickness. You only need to be aware of it when you are using a load worked up for a commercal case, and substituting the commercal case with a NATO case.
Military cases have thickened brass at the case head to help protect them from case head separation durring extraction under stress (ie. fouling, full auto)
The difference in .223 commercal and military brass is so slight, that you can load them side by side (using a moderate load) and not see any difference in pressure signs or on target. Yes I have done that, too.

shortandlong said:
thanks for your input though
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I'm guessing this is sarcasm. Take what I write for what it is if you like.
Go out and see for yourself, ymmv, but I doubt it.
 
The only thing you need to do when loading milsurp brass is reduce the load by 10% due to the slightly smaller internal dimension. Other than that, use the same dies and shellholder.
 
Again, something that isn't always true. I have used alot of military brass from LC'06 to 308 FN to 223 from all over.

Some of this stuff has the SAME volume as commercial brass and used similar amounts of powder. I can only assume that it was rebadged brass from their commercial line up.

I have run into some Euro commercial brass that had significantly LESS volume then US commercial of the same cartridge.

And of course, the differences between different lots from the same company, let alone between companies.

As always, assume nothing. Start at the low starting loads and work up whenever you change ANY component.

Jerry
 
no apology required ......uh oh ! how many people am I PI$$ING off with out intending to .........oh no !!!! the horror:confused:

Anyway i guess there is no straight answer.......it all depends what you want to shoot
I am really enjoying reading these posts though
 
The differences are all very subtle, and are really more 'paper' differences than real differences. It all comes down to the fact that the standards are defined by two different bodies - NATO for military ammo and SAAMI for the civvy stuff. The standards are very slightly different and aren't directly comprable and their lawyers will be quick to tell you that they're incompatible. Back in the real world however, they're interchangable. The usual disclaimers apply, work up your loads, be careful about changing components, etc.
 
Good information here guys, thanks for the posts. :cool:

So let me throw this one out there. I've got an old bubba'd spanish FR8 (mauser 98 receiver). These little carbines were made in the 50s and chambered in 7.62 Nato.

I haven't tryed Nato ammo in it but its proof stamped for it. But I tryed a couple different factory 308 winchester offerings in it and found pressure signs. The cases bulged quite noticeabley just forward of the rim. Extraction was a bit sticky. Lighter Nato loads in Spain? Thicker Nato brass prevents bulging? Nato brass fits the sloppy military chamber better? :popCorn:
 
The military brass will be thicker forcing capacity down but remember the round is a 146gn fnj. There was a spanish round which was lighter in powder and projectile which went through surplus over the last few years, there was talk that this was designed for the FR8. Now if you put a .308 220 grain matchking and stoke the load up it will probably give problems but it should fire cross in circle marked headstamped ammo if it is in good condition. Big IF!
 
Check out page two of the link I pasted earlier, it has a diagram of a military casing and says it is thicker and actually points near the bottom at the rim.

The exerpt with the diagram.

Military brass is thicker. It needs to be. It was made to function and stretch in a wide variety of firearm chambers. Don't forget that the condition of spent brass is of no importance to the service. Like 99% of military brass, it won't be reused.
Where does that leave you? Follow this rule and you won't have any problems.

From what I've read in these posts, it looks like your chamber is slightly larger and the thinner brass of the .308 win is expanding too far, which certainly would explain your trouble extracting.
 
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