.308 vs. .270

[Zak Smith]

Yeah, that's the thing with the .260 (great cartridge that it is), once you seat the bullet out to an optimal OAL, you now have a long action cartridge.

Eh, not really.

What does "optimal" mean? You can seat the bullet in any cartridge out as far as it'll stay in the case, and you'll get more powder capacity, but you'll require a custom chamber in most cases.

With RL17 we're getting 2900-2950 fps with a straight .260 and 139's, and I don't think you're going to get much more by seating at 3.0" vs. 2.85 or 2.9". With RL17, capacity is not an issue. If you loaded H4831SC, maybe, but we're getting less velocity with that at the same pressure signs vs. RL17.

The "260 140" load in the table I posted is substantially identical to the load I just mentioned, or the 6.5x55 load mentioned before.

 

[DIM]

Zak, whatever chamber I got, using 139 gr Lapua Scenar, optimal seating I can get 2.840" that's running into the lands, so in my case I have very little room to workup load... I think in my case, it requires to get throat extended, because its not what I was expecting from long range target stick...
I read your article "6.5mm Shootout: .260 Remington vs. 6.5x47 Lapua vs. 6.5 Creedmoor" and I believe 260 can be used in F open 600 - 1000 yards.

 

[USSR]

What does "optimal" mean? You can seat the bullet in any cartridge out as far as it'll stay in the case, and you'll get more powder capacity, but you'll require a custom chamber in most cases.

Optimal to me means, seating the bullet out so that the bullet base does not go below the body/shoulder junction and you have room for powder. Custom chamber? You simply send a sample non-live cartridge loaded with your bullet of choice, loaded to the OAL that you want. Jack Krieger and Terry Cross throated two of my rifles for me in this manner.

Eh, not really.

Really.

Don

 

[Zak Smith]

By my reckoning, a 139 Scenar will have its base at the body/shoulder junction at about 2.91". I believe this will fit or almost fit in AICS mags that have the front strip removed. In my AW mags I can seat out to 3.0 if I want to. But typically max loads with H4350 or RL17 don't crunch anyway, so it's not an issue, thus it wouldn't be any more optimal in reality.

To elaborate, if powder space were the issue, then seating the bullet out further is one way to solve that. Of the 3 powders that comprise virtually all the long-range match .260 loads, only one of them is limited by powder capacity to my knowledge (ie, H4831SC depending on rifle/brass). The others are limited by peak pressure, not powder capacity, in other words, you hit max pressure before you run out of room for powder. RL17 is faster than H4831SC anyway.

It's misleading IMO to make it sound like .260 is only great if you can seat the bullets way out there. That's simply not true. Of all the guys I know competing (and winning) with it, nobody is running a long action, and most of them are loading to 2.80-2.82 and feeding from AICS mags. The desire to load extra long is not a real issue for .260 performance.

 

[firemanstrickland]

.308!!

 

[DIM]

Zak, can you tell me, what's freebore on the rifle you have in 260 Rem? Another question about load you described for it, what jump you use?
"Final load: 139gr Lapua Scenar @ 2820 fps, 40.7gr H4350, CCI BR2, Lapua .243 brass necked up. "

 

[USSR]

In my AW mags I can seat out to 3.0 if I want to.

Earth to Zak - Most guys can't afford an AI AW, and are restricted by internal magazines which won't handle more than 2.85". It's hell to be common folk, and not have deep pockets.

Don

 

[DIM]

My Savage has detachable magazine, it will handle 3.0, but the chamber won't allow.

 

[d2wing]

The .270 sounds like a better idea on paper and old timers were sold on it by magazine writers. It works just fine for hunting, but never lived up to it's hype. It doesn't offer any big advantage over many other very good cartridges like the .308. If you compare it to it's parent the 30-06 on factory charts, you'll wonder why they bothered. Not that it's a bad cartridge. Just not better.

 

[DIM]

Why bother, well weight was the main reason, how many rounds can soldier carry, plus 30-06 with its long action wasn't working well in new submachine guns, rate of fire was limited. But when they tried rapid fire with 308 the recoil was enormous, so it was quickly changed to 5.56 nato.

Wikipedia:

Work that would eventually develop the 7.62×51mm NATO started just after World War I when the large, powerful .30-06 cartridge proved difficult to adapt to semi-automatic rifles. A less-powerful cartridge would allow a lighter firing mechanism.

The T44 was adopted as the M14 in 1957. Britain and Canada adopted the FN FAL around the same time followed by West German army as the G1. The Germans soon transitioned to a modified version of the Spanish CETME rifle, Heckler & Koch G3. With all three of these firearms, it was clear that the 7.62mm NATO could not be fired controllably in fully automatic due to recoil. Both the M14s and FAL would later go through several variations intended to either limit fully automatic selection through semi-auto version or selector locks or improve control with bipods and/or heavier barrels.

When the M14 arrived in Vietnam, it was found to have a few disadvantages. The rifle's overall length was not well suited for jungle warfare. Also, the weight of 7.62×51mm cartridges limited the total amount of ammunition that could be carried when compared with the common 7.62×39mm cartridge of the Type 56 assault rifles, which the Vietcong and North Vietnamese Army soldiers were equipped with. In addition, the originally issued wooden stocked versions of the M14 were susceptible to warping from moisture in tropical environments, producing "wandering zeroes" and other accuracy problems (this was fixed with the adoption of fiberglass stocks).

Fighting between the big-round and small-round groups reached a peak in the early 1960s, when test after test showed the .223 Remington cartridge fired from the AR-15 allowed an 8-soldier unit to outgun an 11-soldier unit armed with M14s. U.S. troops were able to carry more than twice as much 5.56×45mm ammunition as 7.62x51mm for the same weight, which would allow them a better advantage against a typical NVA unit armed with AK-47s.

 

[RugerMcMarlin]

Any Mauser I ever tried to load for had gobs of lead or free bore. Im guessing something to do with those inch and a half long roundnose bullets. I can see advantage to seating longer bullets. Have you found long free bore to be adisadvantage to loading shorter, lighter bullets?
Or does rate of rifling twist sort of make that a non issue?

Also I tend to factor in amount of free bore jump as part of optimal seating depth.

USSR I love the swede, Had no idea it was used in 1000yd!

 

[RugerMcMarlin]

Also rating a cartridge on how much of it you can carry, sounds like a fix for a supply in the field problem to me.

I've heard this argument over and over, I will grant having more bullets than the other guy is an obvious advantage.

But , when you tell me A cartridge is equal in weight to 2 of B cartridge thats just weight, there is also bulk, or amount of space it occupies, I would suggest that we use mass to express weight and bulk. Remembering that most of the weight is projectile in both cases. Now if 1 cartridge A = 2 of Cartridge B in mass or weight or volume of storage. You can also say A is twice of B. That is the crux of weight advantage arguement. Hell I can carry way more 22lr.

Granted there are other factors in cartridge selection, at least I hope there is.

Adequate cover for 5.56 will not be adequate cover for 7.62.

The test of 8 men against 11 men, sounds intresting but those tests were engineered to prove their hypothesis. It would take a complicated test to beat a simple test
Set up a pepper popper target at 350 meters shoot it with any 5.56 you choose, now same shooter shoot it with any 7.62 you choose.
simple test. should come out to about twice as good.

 

[D*N*R*]

1000 yrds??? ok 500yrds still way out there for hunting. ballistic silvertips(what i hunt with) 270win. 9.8in. less drop--2.3 in. less wind drift(10 mph)--185 fps fater--55 more ft lbs energy. Sorry 308 lovers i dont see it. To each their own.

270 win. Deer hunting perfection.

 

[XxWINxX94]

I would go with the .308 unless you want to do some hunting. 308 is alot cheaper and can be found in surplus at even cheaper prices so you can shoot for fun frequently without too much ammo expense.

.270 your pretty much limited to whatever walmart ammo you can find, which probably won't be that cheap anyway.

 

[USSR]

USSR I love the swede, Had no idea it was used in 1000yd!

Note: that's the 6.5x55 cartridge chambered in a modern receiver. Don't want anyone thinking I'm going to the line with a Model 1896 Swedish Mauser rifle. Actually, the 6.5x55 was quite popular at Williamsport, PA where I shot.

Don

 

[skipbo32]

270 will be expensive to target shoot with. .308 isnt cheap either but you can also get some cheap surplus.

 

[Zak Smith]

I seat at least 0.015" back from where the bullet contacts the lands for safety and reliability. I just screwed off my old .260 barrel and I was still only loading at 2.850. Got 2930 fps from it easy before the throat was completely gone.

 

[DIM]

if my max OAL 2.840" and Zak's seating 2.850 and still has 0.015", then my chamber must be 0.025" shorter, why would someone cut chamber like this, I definitely going to find gunsmith to extend my chamber!

Don, when next shootout in your area, if I get this thing shooting as it should why not give it a try ;-)

 

[Gordon]

My first high power riflein 1963 was a 1953 .270 Win. Model 70 Std rifle with a Unertl Hawk 4x scope with a 1moa dot set to 100 yards and a 1/2 Moa dot set that it hits dead on at 300 yards with 130 grain .270 ammo.I still have it and both Winchester and Unertl knew their stuff as it is still a GTG 9 pound rig that shoots just over MOA with a good load. In the later 70s I started fooling with Magnums and neglected it alot. But in the early 90s out she came for some great northern states hunting.
Now alot older, I am leaning toward the 7.5 pound Featherweights and .308 is a real favorite. I have also extensively hunted and competed with the .308 format in Brown Precision Ultra lights and battle rifles and found it to be about as effective, if not as spectacular as the .270 . My go to deer rifle/plains game rig has been a .270WSM for the last 5 years or so.Spectacular and controllable! But in a potential survival scenario in the real world I'll take the 7.62 Nato.

 

[Zak Smith]

At 2.85 my barrel was toast. When it was new I had to seat at 2.80-2.81" to keep them off the lands.

 

[DIM]

Zak you convince me, I'll work up some loads so far seating 0.015" of lands didn't yield any viable results, I'm getting a minute sometimes more @ 300 same @ 100, my 223 shoots same size groups but @ 600, that's 52 gr A-Max...

 

[Zak Smith]

I'm not sure what I'm supposed to convince you of. I load at least 0.015" off the lands because I want safety and reliability in field matches. I find a load that is accurate and speedy enough within this restriction.

 

[DIM]

At least I stopped worrying about its chamber been to short :-D, because I was getting ready to extend its freebore

 

[RugerMcMarlin]

Gordon, I'm a huge fan of Lee dots and cross hair on hunting scopes , Unertl scopes too.You had it on a fine rifle too. Used to have Lyman 2 1/2 x, w/ fine hair and 3 minute dot. Some guys think those mil dots are a new invention.