260 remington?

[rankroddin250]

reading into the 260 Remington it seems to be a 308 necked down to 6.5.

my question is why do the ballistic charts show that the 308 has much higher velocity than the 260 when using similar weight bullets?

same case, same bullet weight, wouldn't you be able to push them the same speed or even faster with the 6.5?

 

[6.5BR]

Re: 260 remington?

More area on the base of the bullet for the gas to work, more efficiency, ALSO, shorter 308 bearing surface on the bullet = less friction, ALSO, more area in the bbl w/larger hole to burn powder IN bbl, = Higher Expansion Ration, ALSO slower twist = less friction.

Hope that helps.

 

[Mike]

Re: 260 remington?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mica</div><div class="ubbcode-body">
my question is why do the ballistic charts show that the 308 has much higher velocity than the 260 when using similar weight bullets? </div></div>

The 308 shooting a 260 weight bullet (140gn range) will have a higher velocity. However, the BC of a 308 bullet in the 140gn range will be horrible and the round will nearly be useless as an accurate LR round.

Read these and it may help answer your questions.

http://en.wikipedia.org/wiki/Ballistic_coefficient

http://www.chuckhawks.com/bc.htm

 

[6.5BR]

Re: 260 remington?

Now if you are talking a hunting rig to 400 yds, the 130 Accubond in a 260 around 2850 and the 308 w/130 TTSX around 3,000 will be w/in 1/2" of each other at 400 yds w/a 200 zero.

Just depends what you want to do.

Mike's point on BC is very valid when you get to 500+

Never owned a 308, but for hunting to 400, I'd use one.

I feel the 260 and 7/08 are better long distance rounds, and the 6mm version aka 243 is not bad fast twisted, albeit short bbl life.

 

[head2h2o]

Re: 260 remington?

More area on the base of the bullet for the gas to work, more efficiency, ALSO, shorter 308 bearing surface on the bullet = less friction, ALSO, more area in the bbl w/larger hole to burn powder IN bbl, = Higher Expansion Ration, ALSO slower twist = less friction.

+1

Just think about the physics behind it and it will make sense. The 260 shines though at the longer distances. Better BC.

 

[pjparker]

Re: 260 remington?

Mica

Along with what the others have said, it boils down to the same capacity of expanding gasses trying to get through a smaller hole.

The expanding gasses have to push on the base of a smaller bullet to get out.

The area of the smaller bullet is smaller by the square of the radius, so the area available at the base of a .264 bullet is a good bit less than that of a .308.

With equal pressures acting on the base of the bullets, the smaller bullet will have less force acting on it and therefore have a lower velocity.

Paul

 

[sermonator]

Re: 260 remington?

Yes to what's been said which is why many hunters like the smaller bore stuff (long bullets with high SC and BC) unless they need a big bullet shooting things with claws & teeth. You get equal or better performance past 200 yards with less recoil. So...

So beyond 200 yards my .300 WM actually hits harder than my .338, with less recoil. You can shoot a 7mmRM w/ or 30-06 with 160 range bullets and basically the same recoil. Or the .280 with a lighter bullet and less recoil. Both of the 7s are going to hit harder & shoot flatter at long range (400yds).

Randy Brooks (Barnes Bullets) was hunting for quite a while with the .260 as his regular elk gun (& 140s I think). Long bullets (especially the Barnes)have high penitration, even though they might start slower. He was shooting through elk even at long ranges with this outfit.

 

[sermonator]

Re: 260 remington?

Yes to what's been said which is why many hunters like the smaller bore stuff (long bullets with high SC and BC) unless they need a big bullet shooting things with claws & teeth. You get equal or better performance past 200 yards with less recoil. So...

Beyond 200 yards my .300 WM actually hits harder than my .338, with less recoil. You can shoot a 7mmRM w/ or 30-06 with 160 range bullets and basically the same recoil. Or the .280 with a lighter bullet and less recoil. Both of the 7s are going to hit harder & shoot flatter at long range (400yds).

Randy Brooks (Barnes Bullets) was hunting for quite a while with the .260 as his regular elk gun (& 140s I think). Long bullets (especially the Barnes)have high penitration, even though they might start slower. He was shooting through elk even at long ranges with this outfit.

 

[rankroddin250]

Re: 260 remington?

Thank you for your help and wisdom guys. I have used My 7mm Rem Mag as my all around hunting rig for 10 years now. 160 Grain Accubond @ 3050 fps is amazingly devastating and pretty flat shooting. I have kinda gotten into the gas guns the last couple years and hitting my buck twice in the pumper station @ 250 yards with the 55 grain 223 bullet did the job but left a little to be desired in the knock down department.

Im looking into Building an AR10 platform for next year and kinda leaning twards the 243 but exploring the other options too. I know none of the short action loads are going to compare to the magnum Im used to but gotta make a compromise if you want the semi auto. :-(