6.5mm - 25cal = .007"

Even your original was splitting hairs, but it was comparing two bullets of different design, with advantages in favor of the .25, and what is likely excess velocity advantage to the .25 as well. I wish there was a comparable 135gr 6.5mm to compare to the .25. Then you could plug in the same velocity for each and at least be close. The .25 would have a slight BC advantage over the 6.5 if they were the same weight. To be perfectly accurate the 6.5 would have a slight velocity advantage. Honestly that's the issue. SLIGHT. It's only .007". With same weight bullets, the .25 should manage a SLIGHT BC advantage, and the 6.5 should manage a SLIGHT velocity advantage. With same BC bullets, the 6.5 will recoil SLIGHTLY more and have SLIGHTLY less muzzle velocity, but SLIGHTLY more energy and momentum. There's no magic to .257" bullets or to .264" bullets, and both are so close that it's hard to say that one fits in a certain action or even cartridge better than the other.

What point are you trying to make? That the 144 lrht is the superior bullet? That 6.5 is the better caliber? My post was to demonstrate that 25CM with the 135 is a very efficient combo. It seems to be the best of both worlds. Higher velocity than typical 140+ gr 6.5 loads and better BC than all but a few. I stated that if I were starting over, I would build a 25CM instead of the three 6.5CM that I currently own. No reason to dispute that
 
What point are you trying to make? That the 144 lrht is the superior bullet? That 6.5 is the better caliber? My post was to demonstrate that 25CM with the 135 is a very efficient combo. It seems to be the best of both worlds. Higher velocity than typical 140+ gr 6.5 loads and better BC than all but a few. I stated that if I were starting over, I would build a 25CM instead of the three 6.5CM that I currently own. No reason to dispute that
I'm making the points that there isn't a significant difference between the two, and that you seem to be favoring the 25 by comparing hand loaded velocities to factory published velocities for the 6.5CM AND comparing two different bullet designs which in your comparison also favors the 25. Comparing the 135 LRH to the 144 LRH is a much more fair comparison because they are actually from the same product line and both pointed. With the 9gr weight increase the 6.5 CM might actually be 100fps behind the 25 CM, but even so, the difference in results is negligible. I accidentally flipped them at 100fps though, and I messed something at 50fps. At a 100fps disadvantage the 6.5CM looses by 15ft*lbs at 1000yds. At a 50fps disadvantage the 6.5CM wins by 28ft*lbs(not over 100. Oops) at 1000yds. What's my point? They're basically the same! There's not a substantial difference. They're very close to each other.

I built a pair of 6.5-257AI's instead of 257AI's. I didn't do so because one was better than the other. I did so because there is wide spread, mainstream availability of excellent bullets. Although .25cal bullet selection has improved greatly, the good bullets of modern design are primarily only available through niche manufacturers. Berger makes what, 3? Two of them are some of the newest and best designed bullets that Berger makes. While I think availability truly favors 6.5mm the gap is narrowing, and that really just makes the difference negligible. Shoot whichever one you want. Having built some 6.5-257AI's, if someone asked "257AI, or 6.5-257AI?" My answer would be "6.5-284". The reason would be cheaper dies, better brass availability, factory ammo and rifles if that suits you. Does the same dang thing.
 
No favoring here. My real world experiences with my 6.5 CMs with 140 class bullets have shown that 2900 fps is not realistic in 24" barrels, and in fact 2800 fps is pushing it. My shooting partner sends 135 lrht out of his 24" 25 CM with a moderate load of H4350 at 2900+. I ran the numbers with your bullet (144 lrht) in a previous post and it did not show any significant difference versus the 25 CM performance.

So...we've wasted a ton of words to say that they do the same things. Thankfully we can each go build a few and enjoy them. Cheers.
 
No favoring here. My real world experiences with my 6.5 CMs with 140 class bullets have shown that 2900 fps is not realistic in 24" barrels, and in fact 2800 fps is pushing it. My shooting partner sends 135 lrht out of his 24" 25 CM with a moderate load of H4350 at 2900+. I eran the numbers with your bullet (144 lrht) in a previous post and it did not show any significant difference versus the 25 CM performance.

So...we've wasted a ton of words to say that they do the same things. Thankfully we can each go build a few and enjoy them. Cheers.

Yes exactly. They're practically the same. Thats my point.

As far as your friend's velocity results, it's likely that he just has a fast barrel. A drop of only 5 grains shouldn't result in a 25CM beating a 6.5CM by 100fps. It's a shame there isn't good data for both cartridges out there.

From Nosler
25-06 120gr 3177fps
6.5-06 120gr 3294fps

257Rob +P 120gr 2817fps
260Rem. 120gr. 3050fps.

The extra .007" is SLIGHTLY more efficient. BC's of same weight bullets will be SLIGHTLY better for 25. THEYRE BASICALLY THE SAME. That's all my point ever was. I did have a problem with the claim that a 25CM can beat a 6.5CM by 100fps when only dropping bullet weight by 5gr. That's very unlikely on the average. One rifle vs one other rifle, it could definitely happen. On the average, I would guess they'd be mush closer together.
 
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We have factory loaded ammunition for 22, 6mm, and 6.5 creedmoor.
So someone should compare those and see what it shows.
I would use Hornady just because they load all 3 and would be the same type bullet. It doesn't matter if it's a bullet that you would hunt with just so long as the BC's are close.
And pay attention to the distance that each falls below expansion velocity.
You should be able to extrapolate where the 25 creedmoor will fall
 
Big H may not be far from releasing a 25 CM.
I hope they do. Anything that spurs more heavy bullet options I'll take. Count me in the Fudd column on this one because I'm perfectly happy with my 257 Bob Improved, but that thing is so changed from the original that it might as well be a 25 CM.

Maybe Berger will add a .257 EOL to their lineup, something around 142gn.
 
I hope they do. Anything that spurs more heavy bullet options I'll take. Count me in the Fudd column on this one because I'm perfectly happy with my 257 Bob Improved, but that thing is so changed from the original that it might as well be a 25 CM.

Maybe Berger will add a .257 EOL to their lineup, something around 142gn.
Don't over look these guy's 😉
Blackhole bullets.

Screenshot_20240412_111752_Chrome.jpg
 
I hope they do. Anything that spurs more heavy bullet options I'll take. Count me in the Fudd column on this one because I'm perfectly happy with my 257 Bob Improved, but that thing is so changed from the original that it might as well be a 25 CM.

Maybe Berger will add a .257 EOL to their lineup, something around 142gn.
I think that would really enhance the .257" if they kept the form factor in the .915 or lower range the way they did with the 133. They did an excellent job on the 133.

I wouldn't mind if Berger brought out a 145-147gr 6.5mm as well. The 156 was perhaps a bit overkill, and the BC is t quite what was expected. I assume that's because they tried to keep it stable in an 8" twist.
 
Sure we would. The 257 Roberts is a good round. The 25-06 just ballisticaly out performs the 257R. FYI the 6.5-06 is a round and has little to no following.

With the 6.5/06 having little to no following, I tried one. 127-129's at 3150 and 147's at 3000 fps(lapua brass vs 2900 with Winchester brass) on a 26" barrel is real world on an 8T. Add approximately 150 fps for the AI version.

The 260 AI approaches the 6.5/06, but just can't quite get there, but both are exceptional in terms of accuracy.

Another '06 case that has little to no following is the std 280 Rem. I have been shooting the 160-168g bullets at 2900 in this case for 25+ years with IMR 7828 with Federal 210's, only a smidge of powder. I recently tried the 180g eld Match at 2700 fps with R#17 with amazing results because a .796 advertised BC does not suck. At 600, the 180g eldm at 2700 smacks steel like a Mac Truck!

I am scared of putting all my eggs in one basket with a 133g 25 caliber bullet when lots of bullets work in the '06 case in 6.5 & 7mm. Any decent muzzle break negates any recoil issue. In 25 Caliber, for now I will stick with the shortened freebore 257 Weatherby shooting the 110-115s at 3600 in sub 3/8" groups for now.
 
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What is realistic performance expectations on the 25CM?
2850fps plus or minus a little with a 133gr in a 24-26" barrel. That would be normal pressures. If loading up to ejector marks you might bump that 50-100fps. I could imagine a fast barrel, just the right powder and really pushing brass getting up to 2950-3000. Another poster claims a friend is hitting 2950fps with a 135gr. I would expect the average shooter to be in the neighborhood of 2850fps.

A 6.5CM shoots a 100gr bullet over 100fps faster than a 6mmCM. Drop 10gr of bullet weight in the 6mm and the velocity is roughly equal. If a 6.5CM runs about 2850fps with a 140, then a 25CM is going to be close to that with a 133gr bullet, probably a little faster, but not overwhelmingly.
 
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