25-06 velocity?

[mrbigtexan]

I haven't shot my 25-06 over a chronograph yet but my question is why do most manuals list a 117-120 gr bullet going 150+/- fps slower than 130 gr bullet out of a 270 win.? Has anyone confirmed this with identical length barrels?

 

[mrbigtexan]

Also, is the cartridge capacity really that much smaller? The max load shows to be less than the starting load for 270 win.

 

[elkaholic]

Also, is the cartridge capacity really that much smaller? The max load shows to be less than the starting load for 270 win.

There is NO difference in USEABLE case capacity as they are identical except for the neck. I don't know what the manuals say, but I shot a 25-06 for many years and it is possible to get near 3100' with a 24" barrel and the 117's. I'm pretty sure that a 270 won't make 3250' with 130's.......Rich

 

[mrbigtexan]

well thats what i was thinking also

 

[elkaholic]

There is NO difference in USEABLE case capacity as they are identical except for the neck. I don't know what the manuals say, but I shot a 25-06 for many years and it is possible to get near 3100' with a 24" barrel and the 117's. I'm pretty sure that a 270 won't make 3250' with 130's.......Rich

I just got a few manuals out and it depends a lot on which one you look at. It's true that the 270 will probably be 100' faster (avg) but bear in mind that you have a larger base on the bullet which gives you velocity at the muzzle but the b.c. is lower and you lose it quite quickly......Rich

 

[the444shooter]

But the BC's I've seen in standard hunting loads aren't that different between the two, and sometimes actually favor the .270 caliber projectile in respective bullet weights (comparing 100-110gr .25 cal to 130gr .270 cal, and 115-120gr .25 cal to 150gr .270 cal)

I've been racking my brain for the past couple years wondering why so many people consider the 25-06 to be a "long range" round and not giving the nod to a .270. It seems to me that the argument for the 25-06 is strictly anecdotal.

Not to knock the 25-06, because I really would like one because of the light recoil and the relatively flat shooting charactaristics out to 5-600yds, but the .270 trumps it with some of the loads available for it now.

 

[elkaholic]

But the BC's I've seen in standard hunting loads aren't that different between the two, and sometimes actually favor the .270 caliber projectile in respective bullet weights (comparing 100-110gr .25 cal to 130gr .270 cal, and 115-120gr .25 cal to 150gr .270 cal)

I've been racking my brain for the past couple years wondering why so many people consider the 25-06 to be a "long range" round and not giving the nod to a .270. It seems to me that the argument for the 25-06 is strictly anecdotal.

Not to knock the 25-06, because I really would like one because of the light recoil and the relatively flat shooting charactaristics out to 5-600yds, but the .270 trumps it with some of the loads available for it now.

I agree but he was comparing 120's to 130's........Rich

 

[the444shooter]

I agree but he was comparing 120's to 130's........Rich

Right, and I apologize for throwing a tangent in there, but sticking with the OPs question about "117-120" versus 130 in the 270, I haven't seen too many 117 loads with great BCs, and especially in the 120s since most of the 120s I've seen are flat base bullets. A 130 in a 270 gives you just enough mass, diameter, length etc to improve upon the shape, which in turn, coupled with a higher potential velocity in a .270 (3100-3200fps) makes a higher BC and makes it a better performer, does it not?

I really don't have a dog in this fight, but have been mulling his over a lot lately.

And sticking with the OPs original question, I can't say that I've ever seen anyone refute the standard velocity claims of the 25-06 out of a 24" barrel, has anyone else?

 

[elkaholic]

Right, and I apologize for throwing a tangent in there, but sticking with the OPs question about "117-120" versus 130 in the 270, I haven't seen too many 117 loads with great BCs, and especially in the 120s since most of the 120s I've seen are flat base bullets. A 130 in a 270 gives you just enough mass, diameter, length etc to improve upon the shape, which in turn, coupled with a higher potential velocity in a .270 (3100-3200fps) makes a higher BC and makes it a better performer, does it not?

I really don't have a dog in this fight, but have been mulling his over a lot lately.

And sticking with the OPs original question, I can't say that I've ever seen anyone refute the standard velocity claims of the 25-06 out of a 24" barrel, has anyone else?

It's true that the 25 doesn't have a great # of good bullets, but when you compare apples to apples, and stay with the 120 vs 130, here is what you get. (from 1st addition Berger manual)
25-06, 115 VLD .466 G7 b.c. mv 3148' (this is only 115 so 117-120 is higher)
270W 130 VLD .452 G7 b.c. mv one load of 3184 but all the rest right on par with the '06. (the '06 has 2 inches more barrel so the top 270 load would be a little over 3200' with a 26")

Pretty much a wash although another 5 grs. (120) in the 25 would have a higher b.c. but slightly less velocity.

As far as a 130 gr. 270 improving on the shape over a 120 gr. 257, it doesnt hold up. That is why given the same bullet design, the 257 has a higher S.D. and thus a higher b.c.

I agree that the options with a 270 are much greater with bullet selection and weights which is a definite advantage in a hunting rifle......Rich

 

[mrbigtexan]

This is awesome info! It just puzzles me why a lighter bullet out of virtually the same case is slower! I never thought about bullet base size being what would cause the difference in velocity. Also, i didnt realize that the bergers in the 25 had a better b.c. out of the 2. I am glad that bullets are getting better for both calibers since the wsm's are breathing new life into the bullet sizes. It has puzzled me also why the better bullets are mingled into both smaller and larger calibers but these 2 seem to have been left out in the cold.

 

[cdherman]

I have a 25-06, a 270, a 7mm SAUM, a 7 remy etc. Before you convince yourself that it kicks a lot less that your 270, let me say that there is just something not quite right about the recoil calculation that the computer generates. That **** 25-06 puts a bruise on my shoulder faster than any other gun I shoot. My theory (personal, take with grain of salt) is that the overbore guns also generate considerable recoil from gasses and flame. Those are NOT being counted in the programs that predict recoil. But the count in the real world.

In other words, imagine you load a cartridge with just powder, and maybe some cornmeal. And go bang. You will not get hurt of course. But there remains SOME recoil. Yet the recoil programs will not predict any recoil since the projectile was weightless, or nearly so....

Moreover, felt recoil is a function not only of total energy, but of the rapidity of that energy. The small, overbore 25 "punches" you harder than the 270, even though both have similar powder rangers (again, my theory)....

Practically, IMHO, the 25 struggles with bullet availability coupled with factory rifles mostly being unable to handle heavier bullets due to the slow twists. What I can do at the "heavy end" of a 25, I can also do with a good 6mm. And what I can do with the 25 at the "light end", I can do even better with a 6mm.

 

[elkaholic]

This is awesome info! It just puzzles me why a lighter bullet out of virtually the same case is slower! I never thought about bullet base size being what would cause the difference in velocity. Also, i didnt realize that the bergers in the 25 had a better b.c. out of the 2. I am glad that bullets are getting better for both calibers since the wsm's are breathing new life into the bullet sizes. It has puzzled me also why the better bullets are mingled into both smaller and larger calibers but these 2 seem to have been left out in the cold.

Basically, it ties in to sectional density. The lower the sd, with the same capacity case and pressure, the more velocity. i.e. you have a greater cross section for the pressure being exerted pushing the same weight faster (if that makes sense). But then it slows down quicker becasue the same weight is pushing a greater frontal area. This is true if you have no other variables in bullet design...rich

p.s. If you get up the 140 Berger in the 270, then the b.c. becomes a little higher than the 115 because the length/weight ratio changes increasing both the sd and therefore, the b.c.

 

[cdherman]

Here's another curve ball.

For a monolithic bullet, the bullet geometry is scaleable. A bullet that is identical in .243 should behave the same as a .500. Someone correct me if I am wrong...

But in a jacketed bullet, as the caliber decreases, the proportion of the bullet dedicated to the soft and light jacket INCREASES. So the ballistic coefficient suffers.

Propose a mental exercise: The jacket for a .308 might be around .035. That means that a .035" layer of soft light copper is surrounding a relatively large heavy lead core. .308 minus .07 is .238 lead core diameter.

Now, do the same for .223. The jacket for a hunting bullet must remain relatively thick, so perhaps the same .035. .223 minus .070 is 0.153" Note the greater proportional fall in lead core diameter.

Now, perform the same calculation for my hypothetical .070 caliber cartridge. 0.70" minus 0.70 jacket thickness = 0 The bullet has no lead....

Of course this is an exaggeration, but the concept is that as caliber falls, the jacket thickness does not fall proportionally. That means small caliber bullets increasingly behave like monolithic bullets. Generally, the monoliths are great for hunting, but long range work is a problem since their SD are limited.

 

[ValorsMinion]

Here's another curve ball.

For a monolithic bullet, the bullet geometry is scaleable. A bullet that is identical in .243 should behave the same as a .500. Someone correct me if I am wrong...

But in a jacketed bullet, as the caliber decreases, the proportion of the bullet dedicated to the soft and light jacket INCREASES. So the ballistic coefficient suffers.

Propose a mental exercise: The jacket for a .308 might be around .035. That means that a .035" layer of soft light copper is surrounding a relatively large heavy lead core. .308 minus .07 is .238 lead core diameter.

Now, do the same for .223. The jacket for a hunting bullet must remain relatively thick, so perhaps the same .035. .223 minus .070 is 0.153" Note the greater proportional fall in lead core diameter.

Now, perform the same calculation for my hypothetical .070 caliber cartridge. 0.70" minus 0.70 jacket thickness = 0 The bullet has no lead....

Of course this is an exaggeration, but the concept is that as caliber falls, the jacket thickness does not fall proportionally. That means small caliber bullets increasingly behave like monolithic bullets. Generally, the monoliths are great for hunting, but long range work is a problem since their SD are limited.

I dont think it would scale like that because as the length and diameter of a bullet increases, weight would increase exponentially not linearly.

I'm interested in this thread as I am having a hard time deciding what my next rifle will be. I want a light weight hunting rifle for anything I will come across in Texas (deer and hog). I want it in a popular caliber that can be found anywhere that shoots flat and does not have too much recoil. Right now I cant make my mind up between the 25-06 and 270.