6,5x47 against .260Rem.

[Pan]

I understand that the first is judged better than the latter. I even hear about higher velocitys from the '47. Is this because of its shape and economical burning, or what? Normaly bigger case volumes give higher velocity?

Thanks,

Pan.

 

[jb1000br]

Numbers look similar...don't really have enough real world evidence to draw conclusions yet though...stay tuned...

JB

 

[Pan]

Hm...... I must say I had expexted a more spesific answer. Is this forum not were all the experts are?

 

[memilanuk]

Feel free to get your own barrels in both calibers and test away to your hearts content... when you get thru testing all the different combinations of bullets and powders, including the newly released bullets that haven't hit the shelves quite yet, then you'll have your answer.

 

[Pan]

Thank you so much for all your help.

 

[jb1000br]

Hm...... I must say I had expexted a more spesific answer. Is this forum not were all the experts are?

Showing a lot of sarcasm for a newbie...

Uh, there is only a couple people IN THE COUNTRY with rifles so chambered, and most of them probably don't have a 260 to compare it to. Out of them, ONE person has good data that we have shown on the site.

We post info as soon as it becomes available...if you can find the info somewhere else, go for it...

If that is the attitude you are going to have, expect attitude in return...and also expect to go somewhere else to get your questions answered...

 

[Pan]

I humbly apologize if stepping on toes, I did not know the cartridge was that new an unprooved. I just thought that parallels could be drawn between theese cartridges and the 6XC contra .243 Win. My curiosity comes from the fact that theese smaller cartridges deliver simmilar velocities as much bigger cases. Close to 2900 f/s with a 139 grs bullets in the 6,5x47, that is almost impossible to reach in a 6,5x55 with a 26" barrel at normal preassures. Bigger volumes have always spoken for higher velocities. Whats new?

Sorry again if impolite, english is not my native language.

 

[Mark Walker in TX]

Pan,

It is all about efficiency. Read through the info on the 30BR as an example. A 30BR will shoot a 118 grain bullet faster than a 6BR will shoot a 107 grain bullet, logically this would not be so, but, the increase in efficiency makes it happen.

Mark

 

[Pan]

Pan,

It is all about efficiency. Read through the info on the 30BR as an example. A 30BR will shoot a 118 grain bullet faster than a 6BR will shoot a 107 grain bullet, logically this would not be so, but, the increase in efficiency makes it happen.

Mark

Thanks for reply, Ranger, but to me that is not very strange, since we here are talking same volume and different bullet diameter. Then it is clear that the one with the biggest diameter will achieve biggest velocity, when bullet weight is equal.,118-107, close enough)

But that a 6,5x47 Lapua delvers 100 f/s more than the 6,5x55 with same bullet weight is - interesting!

 

[JER]

I think the complex interactions between powder burn rate, case diameter, case length, and bore diameter,plus some other factors that I haven't guessed) are not very well understood.

However, empirical observations would lead one to believe that there is an optimum ratio or relationship between case length and case diameter for a given bore diameter that results in markedly more efficient propellant combustion. Such efficiency then leads to muzzle velocities all out of proportion to what we have come to expect from the powder amount in question.

 

[Forum Boss]

Here's what I take from Darrell Jones' recent testing on his 6.5x47.

139-142 grain bullets: Expect 2800-2860 fps, about what a .260 can deliver.

120-125 grain bullets: 3050 fps comfortably. That's about 50 fps more than a .260 with a long barrel. My 24" .260 maxed out at about 2960 with a 123gr Scenar.

Darrel took the 120s all the way up to 3150+ fps. That was tough on brass and the accuracy was much better at 3000-3070. I'd say 3100 is doable though.

Again, you have factors of bore dimension, bullet diameter etc. which will affect max speeds.

 

[MattPeetz]

Moderator

Isn't Darrell using a Schneider barrel? A tighter bore will make a differance.

I believe Darrell has a 28" barrel too. Will have to look back in my emails.

The 6.5x47 and the 260 are very close but the 260 still has the advantage. Nonetheless, the 6.5x47 does show alot of promise.

 

[Mark Walker in TX]

...The 6.5x47 and the 260 are very close but the 260 still has the advantage. Nonetheless, the 6.5x47 does show alot of promise.

And that advantage is???

Mark

 

[MattPeetz]

Mark

For velocity.

I am getting 3160fps comfortably with the 120's. On my 3rd reloading now.

I am going to switch powders with the 120's. I am using N-160 right now but am going to get some Rl-22 loads up and running. Rl-22 got the same speed as N-160 but with considerably less pressure.

I have a 30" broughton. 2" inches more than Darrel.

 

[AlanPF]

Would I be right in assuming that quality and thickness of the brass around the case head has a big bearing on what pressure it will stand, and therefore what velocities can be achieved,without being too hard on the brass)? So if the 6.5x47 Lapua brass is very good, then I guess it may well outperform cases with a greater capacity.

Forgive me if its already published somewhere, but has anyone measured the water capacity of the latest 6.5x47 brass, and compared it with the 260 Rem and the AI version?

I might add that we who aren't at the bleeding edge of new cartridge development, are indebted to those who are prepared to take the time and trouble, particularly when they're prepared to share their findings.

Alan

 

[JER]

Mark

For velocity.

I am getting 3160fps comfortably with the 120's. On my 3rd reloading now.

Still not much of an advantage. A Lapua 123 at 3100 drifts a whopping 3/4" less than the same bullet at 2800 fps at 300 yards in a 10 mph full value wind.

Such a trivial amount is not worth the barrel burn and recoil that those extra 300 fps bring. At least not in Highpower.

I use 139s at 2700 for 600 yards, so the reason to shoot 123s at warp speed makes no sense to me there either.

I do shoot a 260 Rem, BTW.

 

[Forum Boss]

Water capacity of 6.5x47 Lapua

Darrell's first lot,obtained from Europe direct) = 49.0 gr H20

Darrell's second lot,obtained from Grafs.com) = 47.0 gr H20

The first lot, Darrell said, had slightly longer necks. Also the latest export lot may be slightly thicker.

 

[LRCampos]

I know it is an old post, but I think the theme is very interesting today.
Can I ask if the case size and dimensions of the 6.5x47Lapua can be better for accuracy than the longer .260rem case?

 

[mysticplayer]

NO, case size in your comparison will not be the limiting factor for accuracy.

There are many very accurate 260R and AI's. Also, 6.5-06's and 6.5-284's.

It is about matching all the components to the barrel/rifle. Then some barrels shoot better then others.

If you could make different size brass to the same specs as the Lapua,ie 260R, 6.5X57, 6.5-06), case volume would determine the max performance all else being equal.

Assuming you have a powder that will work, the larger the case, the faster you go.

Jerry

 

[RDesJardin]

I agree with mystic this is just the new version of the .308 Win vs the 30-06 SPR battle, Comes down to bullet selection and destined use. 6.5 anything works.