Been Comparing 243 and 260

[JayCarver]

Yes another 243 and 260 thread, just what we all needed right but please hear me out before you post "really! another 243 vs 260 thread. I have been searching this subject for quite a while as there is lots of info out there about this subject but my findings while running the numbers don't seen to favour the 243 as much as every ones comments would seem to apply.

I have a AXMC 308 ordered, I'm going to pick up a 6mm or 6.5mm barrel for it. I have been running the numbers on JBM comparing some of the popular bullets, perhaps I'm not using the right velocities but it's looking much better than I thought it would for the 260 which surprised me because all I hear is how much better the 243 is, what am I missing or doing wrong?

140gr AMAX
2840 fps
Temperature: 59.0 °F
Pressure: 29.92 in Hg
Humidity: 30 %
Altitude: 2500.0 ft
10MPH 90deg Wind

Range Yds - 500 1000 1500 2000
Drop MOA - 8.3 26.3 55.3 102.9
Drift MOA - 2.6 6.0 10.8 16.2

105gr AMAX
3050 fps
Temperature: 59.0 °F
Pressure: 29.92 in Hg
Humidity: 30 %
Altitude: 2500.0 ft
10MPH 90deg Wind

Range Yds - 500 1000 1500 2000
Drop MOA - 7.2 24.5 55.1 107.7
Drift MOA - 2.8 6.7 12.6 18.5

I'm seeing less wind drift with the 260 and the drops are pretty close and then better for the 260 at 1500 and beyond???

Thanks in advance for any help.

 

[FALex]

from what I have seen, your numbers are about correct. My experience against .243's has been that they have less drop at various distances, but windage is the same or better in the .260's.

When I was contemplating caliber swap, and running numbers, the drop was insignificant because on the .260 it is still great (compared to the .308 I was shooting). Furthermore, the barrel life on that .243 is going to be less than the .260.

I have shot my .260 out to 1300 with success, but it has been very limited. Do you plan on shooting out to 1500+ regularly?

 

[aqualung]

Why only look at 105 A-max? Check out the ballistics on the 115grn DTAC. around 2895fps out of a 6XC. That's not pushing it either...

You could also look into 6XC and 6mm Super LR.

I just used a 6XC, only out to 800yds, but the drift (lack of) was awesome. The lead on movers was a good MIL less than .308 at 400yds. I shot both on consecutive days...

N

 

[redneckbmxer24]

Good luck spotting hits and misses with either of those at 1500+. If you're serious about ELR you need to be looking at a magnum.

 

[BoilerUP]

Use data for the 6mm 105 Hybrid; it is the de-facto "go-to" 6mm comp bullet these days.

 

[JayCarver]

Do you plan on shooting out to 1500+ regularly?

No not really, the place I shoot most goes out to 1200yds so most of the shooting will be inside of that range, I do have places to shoot 2300+ but I leave that for the 338.

Why only look at 105 A-max? Check out the ballistics on the 115grn DTAC. around 2895fps out of a 6XC. That's not pushing it either...

I looked at the 115gr DTAC numbers at 3000 fps and can't remember what the numbers were but I'll check it out again.

Good luck spotting hits and misses with either of those at 1500+. If you're serious about ELR you need to be looking at a magnum.

I do have a 338LM with a 30" tube, just looking for something that falls in between that and the 308.

Use data for the 6mm 105 Hybrid; it is the de-facto "go-to" 6mm comp bullet these days.

Thanks I'll check this one out too.


Thanks for the replies guys, I'll do some more research and post what I find out.

 

[rrflyer]

Your 6mm numbers are slow.

3150fps isn't hard to reach.

Windage will be close but you'll have a full mil or so less drop at 1,000

You can get close to 6mm performance using the 130s at 2950 fps



The 6mm really shines for me off barricades and odd positions. If all I was doing was prone shooting I'd be using a 6.5 for more energy and easier to see misses.

 

[wrhunter]

If you use the 105 hybrid make sure you compare it with the 140 hybrid.

 

[xdeano]

Look at the 105grn jlk .560 g1bc.
Look into the 6slr or 6 compmatch.
Xdeano

 

[Marcoman]

I posted this in another 6mm thread but here it is again:

I rebarreled a TRG-22 with a 7.5 ROT Bartlein and chambered it in 6SLR. I am getting 105's comfortably above 3200fps and 115's around 3100. I should say that those velocities are from a 28.5" barrel and pressures are acceptable (to me).

I settled on 105 Scenars over H100V at 3250fps as my main load. I originally worked with H1000 in the interest of trying to maximize barrel life but found this powder less than satisfactory accuracy wise despite others reporting success with it. In general I have found it to be a bit of a tricky cartridge to tune.

I'm hoping to work up a good load this summer with the 105 Hybrids. They truly seem to be the best combination of weight/BC. Well, those and the D-Tacs but they're are almost impossible to find in Canada.