260 Remington or 308 Winchester?

[MOcaster]

First question, do questions about AR-style rifles go in the military section or factory section? It has confused me the whole time I've been on this forum.

Second and actual question. I want to get a long range AR-style rifle. I'm thinking about a DPMS 260H or a DPMS LR-308. I was told by someone that knows his stuff that the 260 is a better long range round. What say you? I can make 260 Remington brass from 308 Winchester brass, correct? Of course, I'll be reloading, so if I can make 260 Rem from 308 Win, let's call component availability equal. Oh, I want this to be a thousand yard gun, so I will probably upgrade the trigger. I might not be able to hit at a thousand yards or get a range for it, but I want the best round for it. Thanks for everybody's help.

[Randy C]

Have you read this I have looked into buying a 260 but I have a 243wssm for now, http://demigodllc.com/articles/the-case-for-260-remington/
Some one posted this search engine on another post type in 260 Rem and you will have a lot to read, I just tried it and I will be using this. I like this one better than what I've been doing.
https://www.google.com/cse/home?cx=001951264366462437169:ggn3vg-bjum

[MarkP]

When comparing the two rounds, in particular, bullets of equal ballistic coefficient the 260's bullet will be lighter thus less recoil. At 1,000 yds BC will strongly dictate the wind drift, a lower BC is difficult to compensate for with velocity alone. Such as firing a lower BC bullet at a high velocity versus a high BC bullet at a moderate velocity. Barrel life would be better with the 308 as compared to the 260 a 7mm-08 may be a worthy candidate as well. 162 gr 7mm bullets will have a BC similar to 308's in the 200+ gr range with better barrel life.

[MOcaster]

Thanks for the article, Randy. I just read it and it reaffirmed what I was thinking. The search link will come in handy too.

[Larry Gibson]

However, consider the length of barrel you are going to have(?) and the actual ballistics you'll get from and AR platform and barrel length.

Larry Gibson

[MOcaster]

Barrel length is important. I was thinking about a 20". I would kind of like an 18" for maneuverability, but I'll be losing a couple hundred feet per second from a 24" barrel. I think the 20" would be a good compromise.

[UBER7MM]

....I can make 260 Remington brass from 308 Winchester brass, correct?...
.
Reformed 308 brass will be a tad shorter than 7mm'08 Rem, 260 Rem and 243 Win cases. That may or may not be a issue in an auto loader. Perhaps other members have some experience on this topic.

[MOcaster]

So it would be better to use 243 brass?

[supersniper]

243 brass is easliy converted to 260 just by necking up

[Larry Gibson]

Barrel length is important. I was thinking about a 20". I would kind of like an 18" for maneuverability, but I'll be losing a couple hundred feet per second from a 24" barrel. I think the 20" would be a good compromise.

Oh, I want this to be a thousand yard gun

You might then check the ballistics of each cartridge from a 20" AR barrel with you bullet of choice and determine if either will stay sonic to 1000 yards. The gas gun will limit how hard you can push a bullet unless you don't mind beating the rifle to an early death. Lot's of experience M14/M1A shooter around who have shot 1000 yard matches with 22" barrels know of the difficulty. The 175 gr MK is the bullet of choice but you need 2550 fps out of it for consistent 1000 yard work and that's a hard velocity to get out of a 20" AR w/o beating it to death.

As to the 260 Rem consider the bullet length of a MK of equal BC to the 175 MK and it's seating depth to fit in a mag with an oal of 2.815+/-".

What those 2 cartridges are capable of in bolt guns with longer barrels is different than what they will do in a 20" barreled AR.

If you go with the .308W I suggest a 12" twist which is best for 147 - 175 gr bullets at the velocities the AR will produce.

Larry Gibson

[Doc Highwall]

The shorter 20" barrel will favor a smaller expansion ratio meaning the larger caliber will lose less velocity and in this case 308 vs. 260 the 308 wins.

[nicholst55]

My understanding is that some folks using the .260 for long range built their rifles on long (bolt) actions to allow for long-seating bullets and a corresponding increase in powder capacity. If I was going to build one, that's certainly what I would do. In an AR, I feel that you're really limiting your potential by chambering in .260, especially with a 20" barrel. I would want a 24" barrel,myself - probably for either cartridge being discussed. To me, a 'short, handy' rifle and 1,000-yard capability are somewhat mutually exclusive. I realize that it is being done with 20" barrels, but it's not the route I would personally choose.

[MOcaster]

You all make good points about barrel length. A 24" barrel really wouldn't be that hard to maneuver with practice. It's not something that is that important to me, just something that would be a nice plus if it was easy to maneuver.

[ELFEGO BACA]

Three years ago I purchased a DPMS260H.
I am happy with it but I mostly shoot cast bullets out of my Swede!
Referencing Nosler #7 guide the 260 Remington shooting Custom Competition bullets, 140grain vs the 308s 190 grains, has a velocity advantage of 200 ft/sec - 2800 ft/sec for the 260 vs 2600 ft/sec for the 308!
The ballistic coefficients are the same.
I prefer 6.5 calibers.

Have a good day!

[Multigunner]

Some believe the .260 Reminton has less wind drift than the .308 but I found they were comparing the .260 with ballistic tip bullet to the .308 with conventional bullets.
I looked up a chart of .308 performance with a balistic tip bullet and compared this to the chart for the .260 and found the .308 had much less wind drfit at longer ranges when both used bullets of the same construction.

[Randy C]

I have found that my 308 don't group to its potential when I try to hot rod the gun, its a tack shooter with the right powder charge. I bet the .260 Remington will be the same If you do a special build you cant go wrong with either way.