I am contemplating getting a rifle for growing grandkids in 308 Win.

Before venturing into what would be a new cartridge for me, I would like to learn a little about the wildly popular 308.

The following quote from AmmoGuide raises some basic questions:

quote:

Key differences exist between military and commercial designs, notably in the hardness and thickness of the brass as well as the external dimensions of the case itself. The shoulder and neck of the military design dictate they are farther from the rim by .013 inches (commercial spec shown above), resulting in a significantly different headspace situation between the two rounds. The combination of shorter commercial ammunition in the slightly longer military chamber presents a possibly dangerous situation due to the emergence of a gap in the mating of case and chamber shoulder surfaces.

AmmoGuide lists the distance from the bottom of the case to the shoulder as 1.5598". So apparently there is a military standard with a distance of 1.5728".

How does one know what chamber a rifle has?
For example, would a Kimber have a chamber designed around 1.5598" or 1.5728"?
How about a Ruger American?

I would assume that both use the 'shorter' chamber, since they are commercial offerings rather than military.

The same questions rise with brass.
I would imagine that Hornady and Winchester brass used the short shoulder.
However, what about a foreign entity like Prvi Partizan? They have a good reputation for brass in general. Which shoulder length do they design for?

Thank you for your help.

All US commercial rifles that are marked 308, will have a 308 Winchester chamber; NOT a 7.62 Nato chamber.
I have fired literally thousands of 7.62 ammo in 308 chambers and vice versa. No issues.
Realize that the SAAMI allowable difference in a max 308 chamber and a min 308 cartridge is .013.
If your brass or ammo is marked 308 Win, then it is 308 Win.
This is not something to over think. The only issue is that 7.62 brass is usually thicker so start with starting loads and work up from there.

Thanks, dpcd.
Easy answers are nice.

And a control-feed would even help headspace a sloppy SAAMI chamber. It's hard to believe that a round for such a reputation for accuracy would have such design ambiguity. So be it.

There is no ambiguity; 308 is controlled by SAAMI specs; they just happen to be far more sloppy than people realize. 7.62 is specified by NATO and the specs are so close to a 308 as to make them interchangeable.
Now, CRF extractors are usually not that tight. I have fired hundreds of 7.62s in 30-06s and 7.65 Argentines, both CRF and push feeds; no problems noted. "Headspace" and all it's manifestations is widely misunderstood by lots of people.

I only have one caution for you. never buy used 7.62 x 51mm NATO brass off of the internet. It will have been fired in machine gun, and you can't resize it enough to fit in a regular rifle chamber. Learned that one the hard way. otherwise, just have fun. Hirtenberger Berdan primed ammunition is pretty hot, but it won't blow up anything on you. Have fun.

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I have fired hundreds of 7.62s in 30-06s and 7.65 Argentines, both CRF and push feeds;

DPCD, I have a curious question:
How can you fire a 7.62x51 in a push-feed 30-06?

My guess: the taper on the 7.62 is straighter, less taper, than the 30-06, so the 7.62 headspaces off of the chamber wall. Yes?
The 308 tapers at 0.0120"/inch, the 30-06 at a more slanted 0.0165"/inch.

I once put a 270 in a 338WM push-feed accidentally. It didn't fire.
That woke me up out of complacency. Never again!

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Originally posted by 416Tanzan:
I am contemplating getting a rifle for growing grandkids in 308 Win.

Before venturing into what would be a new cartridge for me, I would like to learn a little about the wildly popular 308.

What is attracting you to this cartridge for your growing grandkids especially if having some concern over the possibilities of differences between the commercial and military chamberings. Here in NZ the 7mm-08 is far outsripping most other cartridges in popularity for new rifle purchases.
Presumably you have considered the 7mm-08, a great performing, easy shooting and easy reloading cartridge, as a candidate for your purpose, and off course it is produced in the same short action lightweight rifles as the 308?

The 308 often has ammunition floating around in places like Africa. While I wouldn't hunt with military stuff, it might get used for plinking.

The main question for planning and reloading is if I used brass like Prvi Partizan. That has been answered.

On choosing the caliber, the 7-08 is a great round. But this is for Africa and I like larger bores if someone will be shooting a hartebeest or wildebeest. Frankly, I prefer a 338, but the grandkid would need to know how to shoot pretty well before using a 338 and s/he would probably be a teenager already.

The 308Win has a listing by Barnes website for 175gn LRX at 2728fps. Even at 2600-2650 in a 22" barrel and potentially looser commercial chamber, that is a pretty decent hunting load where dangerous game roams and one never knows what one may come up against.

However, pre-teen grandkid rounds might only be a 130gn TTSX at a modest 2600fps up to 2800fps, very similar to modest 7-08 potentials.

1; I have indeed, sized, loaded and fired, many hundreds of 7.62 brass fired in M240 Machine guns. You just need a FL die that will push the shoulder back as they are quite springy. I modify standard ones to do that.
2: How to fire 7.62 ammo in a 30-06 push feed? Load them and fire away. The shoulder will jam into the 06 chamber. Now, my friend has a Savage and it won't work in that doe to a tighter chamber, but I have done it in lots of others. You end up with a long 45 ACP case.

I had a surplus military rifle chambered in 7.62NATO and fired lots of 308Win brass through it, so I don't think there is much difference in the chambers, however I never fired factory loaded ammo in this rifle. I consider the difference of these chambers the same as the differences of the 223 compared to the 5.56mm chamberings, which I have never noticed any problems firing hand loads in this rifle either.

I buy bulk Lake City 7.62 brass for my .308 Savage bolt action.

If you have a hard time sizing the cases fired in a machine gun with a standard die you have two choices. You can size the cases first with a 30-06 die or a carbide .45 ACP die. Then size the cases with a standard or small base .308 die.

The standard thumb rule with 7.62 brass is to reduce your charges 1 to 2 grains. But this can vary so its best to make a workup load. I have read that the newer Lake City cases are made with harder brass and have more case capacity.

Below from Dan Newberry of OCW or "Optimal Charge Weight" fame. As you can see he tells you to reduce the charge by .4 grains for LC cases.

http://www.sniperforums.com/fo...ading-data-only.html

All Winchester brass. Reduce by .4 grains if using Lake City, or Federal brass. Reduce by .3 grains if using Lapua brass.

155 grain Sierra Matchking (or any comparable 155 grain match bullet)
45.6 grains of IMR 4895
or
46.5 grains of Varget, IMR 4064, or W748
there is a high node with Varget at about 47.8 grains (Nosler's max is 48 grains).

168 grain Sierra Matchking (or any comparable 168 grain match bullet)
43.6 grains of IMR 4895 (my all time favorite accuracy load)
or
44.5 grains of Varget or IMR 4064 or W748
there is a high node with Varget at or near 46 grains, Hodgdon's max...
or
39.0 grains of IMR 3031 (slower, but very accurate to 300 yards, a great close range tactical load).

175 Sierra Matchking
43.5 Varget, or 45.0 Varget (high node, be careful).
or
42.4 grains IMR 4895
or
43.4 grains of IMR 4064 (high node)
42.2 grains of IMR 4064 (low node)
or
43.5 grains of RL15

With 178 AMAX (Hornady)
42.0 grains IMR 4895
or
43.1 grains of Varget

quote:

Originally posted by 416Tanzan:
The 308 often has ammunition floating around in places like Africa. While I wouldn't hunt with military stuff, it might get used for plinking.

The main question for planning and reloading is if I used brass like Prvi Partizan. That has been answered.

On choosing the caliber, the 7-08 is a great round. But this is for Africa and I like larger bores if someone will be shooting a hartebeest or wildebeest. Frankly, I prefer a 338, but the grandkid would need to know how to shoot pretty well before using a 338 and s/he would probably be a teenager already.

The 308Win has a listing by Barnes website for 175gn LRX at 2728fps. Even at 2600-2650 in a 22" barrel and potentially looser commercial chamber, that is a pretty decent hunting load where dangerous game roams and one never knows what one may come up against.

However, pre-teen grandkid rounds might only be a 130gn TTSX at a modest 2600fps up to 2800fps, very similar to modest 7-08 potentials.

Agree the African thing does put another perspective on your selection at the top end although a similarly good 160gr in the 7mm-08 would be nothing to laugh about. I was thinking more of pre-teens where a 120gr from the 7mm-08 for plinking and small to medium hoofed animals would be about ideal.
Ammo availability in far away places probably does favour the 308.

At the moment starting to look at a 410 shotgun for my 6 year old grandson, our wildfowl season starts in three weeks time but it might be just a bit too early for him. plenty of bunnies where he lives so probably needs a year on them before taking on ducks. He shoots a 22RF and a suppressed Ruger 223 now and can frighteningly well load and rack a bolt action. Good luck with yours.

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Originally posted by eagle27: At the moment starting to look at a 410 shotgun for my 6 year old grandson, our wildfowl season starts in three weeks time but it might be just a bit too early for him.

The traditional nay-saying retort to suggesting .410s for really young kids is bunk. It reflects failure to discriminate between a starter shotgun and a beginning training shotgun.

There's positive to be derived from fun with shotguns long before. My son inkballed his first (flying) clay target 2 weeks before turning 7. He used a Winchester M-20, choked full. He had to break every singles presentation on a skeet field with it before we'd spring for a 20 ga gas gun. Didn't take long.

.410 didn't hurt him any, as he was eventually state NSCA SubJR-ch and then JrCH successive years.

my issue was length, not diameter.

Right; it is always length, hence the need for a shorter die; not a small base die, which are rarely, if ever, really needed. I face off .020 from the base of the standard die and that gives you enough room to adjust them to push back the hard and springy military shoulders.

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Originally posted by dpcd:
Right; it is always length, hence the need for a shorter die; not a small base die, which are rarely, if ever, really needed. I face off .020 from the base of the standard die and that gives you enough room to adjust them to push back the hard and springy military shoulders.

Or, face off a similar amount from the surface of the much cheaper, and usually softer, shell holder. Either method lets you push the shoulder back further when needed.

quote:

And a control-feed would even help headspace a sloppy SAAMI chamber.

No, it wouldn't. A "controlled feed" extractor will hold a case somewhat rearward compared to a push feed action, but the tolerance in the extractor won't make much difference when the problem is cases that are too short at the datum point.

But you already have your answer: There is no more variation in .308 chambers than in any commercially manufactured rifle. Military brass does tend to be thicker, and therefore is of less capacity, so charges sometimes need to be reduced compared to when using more capacious commercial brass.

Its not a problem, both are within specs..I shoot turkeys in Texas with the milsurp stuff and deer with hot handloads.

quote:

Presumably you have considered the 7mm-08, a great performing, easy shooting and easy reloading cartridge, as a candidate for your purpose, and off course it is produced in the same short action lightweight rifles as the 308?

I add another vote for the 7mm-08. I think it is a little better for hunting than the .308 Win. It is much easier to manage than the 308. Its primary hunting bullet weight is 140-grains versus 165-grains. Am building one for my wife. (and will use it also).
Of course, Tom is correct to mill some length off the bottom of the 308 Win Sizer. My solution was to have my first wife stop by a place called "The Site" in Mount Caroll, Illinois. They were finishig up a precision rifle class. She came back with a five gallon bucket mostly filled with Federal Match .308 Brass. Still have plenty of that left. If you take a precision rifle course, bring along five of the Orange Home Depot buckets.

Good luck with your endeavors in this regard.