.243 vs .308

[swarrick]

Re: .243 vs .308

Steve123- So you would go with a 6x47L over the other 6mm's? I think I am sold on a 6mm for my next barrel but just unsure witch one. Well Except for one other cartidge how does the 6x47L compair to the 6.5x47L?

 

[steve123]

Re: .243 vs .308

I like 6x47L.

There's no perfect cartridge but here's why I prefer it.

1.Lapua brass!
2.64,000 PSI rating I believe.
3.Small rifle primer.
4.PPC sized flash hole that's drilled NOT punched.
5.Compact efficient design
6.Good ballistics,115's-.545BC/3100fps,105's-.532BC/3150fps with less than 40 grains of R-17.
7.Low recoil
8.Short case that enables bullets to be seated out of the neck shoulder junction and still fit a short action mag with plenty of room to chase the lands as barrel wears.
9.Decent barrel life.My last barrel went to 2450 rounds.Gotta pay the price for performance.
10.Ridiculously accurate!

6.5x47L would be my second choice.Pretty much the same BC of bullets 123's-130's going around 2950 fps but has better barrel life.Just guessing at 3000 to 4000 rounds.

708AI with 180's slowed down to 2750 fps has me intrigued right now.Hoping for 4000+ barrel life.

Steve

 

[6mmFan]

Re: .243 vs .308

Swarrick,

According to the 1000 yard benchresters the 105s and 107s are more accurate than the 115grain MK- although Steve has had great luck with them. Most 1000 yard Benchers are using the 105grain Berger VLD. I have had good results with this bullet into the lands around .005". I currently use the 107 grain Sierra in my 6XC because I don't have to worry (as much) about a bullet getting pulled out when ejecting an unfired round. Supposedly if you work at it you can also get the Berger VLD to shoot very well off of the lands.

I do not think that ballistically there is any advantage to shooting the 115 grain bullets out of any 6mm because you are swapping velocity for BC. At that point there is just too much friction. Not that they are worse ballistically- they are just not any better. Perhaps if you want to keep them under the 3100 fps mark for accuracy- but this is mostly theoretical.

Steve has had good luck with the 115s. He may not agree with me on some of this, but that's OK.

Steve makes some very valid points about the 6x47L. Doing it over I think I would choose that over the 6XC.- or maybe just the straight 6.5x47L

I would not use the 6BR in a Tac rifle due to feeding problems. Perhaps only with an Elisio tube gun.

Next time whatever chamber it has I will have Hornady make me a custom FL sizing die.

Dirk

http://www.stickerballistics.com/

'I believe that banking institutions are more dangerous to our liberties than standing armies. If the American people ever allow private banks to control the issue of their currency, first by inflation, then by deflation, the banks and corporations that will grow up around the banks will deprive the people of all property until their children wake-up homeless on the continent their fathers conquered.'
Thomas Jefferson

 

[steve123]

Re: .243 vs .308

6mmfan,

I'm tending to agree with you on using the 105-108gr bullets.

Concurring with what you said about the benchrest shooters and equally with Bryan Litz's new "Actual BC's" for Berger bullets.I think originally the stated BC for Berger VLD 115's was .595 but now actual BC is .545.So the difference in BC compared to the 105 VLD's isn't as much as we used to think.

I'll be switching over to 105gr class of bullets from now on for the soon to be finished new barrel as long as I can find an accurate load in the 3100-3150fps range.Hopefully even a little better barrel life too.

Steve

 

[6mmFan]

Re: .243 vs .308

Steve- if thats the case I would go with a 1 in 8 twist and have the smith make the throat specifically for 105-108.

 

[steve123]

Re: .243 vs .308

Too late with the twist!The 7.5 twist Schneider is at the Smith right now.

I'm having it throated so 115's are just in front of the neck shoulder junction.Still plenty of neck for 105's.

I wanted to have the option to use 115's if necessary.

Steve

 

[scotharr]

Re: .243 vs .308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: steve123</div><div class="ubbcode-body">swarrick,

Why not send 105's at 3100+ fps with the 6x47L!!It's a walk in the park for this cartridge.I got them up to 3312 fps with R-17 before the bolt on my gun even got sticky.Just saying.


</div></div>
The 6x47 has several grains lower capacity than 243WIN and you are sending it about 100fps faster.....wonder what pressures you are running at. If you are interested in pure speed with the 6mm, its hard to beat a 243WIN. All these other calibers (6XC, 6x47 Lapua, etc) were an attempt to get "243-like" velocities with less barrel wear by using a few grains less powder charge.

 

[steve123]

Re: .243 vs .308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Scooter-PIE</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: steve123</div><div class="ubbcode-body">swarrick,

Why not send 105's at 3100+ fps with the 6x47L!!It's a walk in the park for this cartridge.I got them up to 3312 fps with R-17 before the bolt on my gun even got sticky.Just saying.


</div></div>
The 6x47 has several grains lower capacity than 243WIN and you are sending it about 100fps faster.....wonder what pressures you are running at. If you are interested in pure
speed with the 6mm, its hard to beat a 243WIN. All these other calibers (6XC, 6x47 Lapua, etc) were an attempt to get"243-like" velocities with less barrel wear by using a few grains less powder charge. </div></div>


Scooter-PIE,

I don't claim to understand the phenomenon as to why 6x47L produces so much velocity.I assure you it does though.That's just how the cartridge performs.It's just an efficient case design.The pressures couldn't be super high to achieve 3100+ with 105's or the bolt would be hard to open.IIRC 243win cases are designed for around 53,000 psi vs 64,000 for 6.5x47L case.

Also part of the reason also is that R-17 powder helps produce more velocity.

Steve

 

[sermonator]

Re: .243 vs .308

Take the savage, put it in a good stock (bedded right) screw on a LW or Shilen barrel in .260 and you will have a .5 MOA gun that will give twice the barrel life of the .243 (which probably one maintain .5 MOA more than 1500 rounds) and almost as much barrel life as the .308 w/ less recoil (making it easier to shoot well).