25-06 velocity?

[sbhooper]

Personally I think it would come down to personal preference as far as small to moderate game hunting. The .270 would definitely offer more options, but the 06 will work fine, too, for Texas hunting. I think that I would split the difference and get a .260 with a short action.

The bottom line in the velocity discussion, is that the longer a bullet is for caliber, the slower that you can push due to the increased bearing surface. That is why the 6.5 bullets generally are slower than others. They are very long for caliber and it takes a lot more to push them faster. The high bc of the long bullets pays off down range, but it starts slower.

Just my take on it anyway.

 

[hemiford]

I believe barrel length and expansion ratio must be considered too.

270 and 25-06 have virtually identical powder weights, so to compare

apples to apples, they must also be given virtually identical barrel volumes,

so that the burn expands into a virtually identical volume and performs

a virtually identical amount of work on the projectiles.

A quick calculation shows that the 25-06 barrel should be 1.162 times

as long as the 270 barrel. So, for example, a 24-in 270 barrel would yield

the same expansion ratio as a 25-06 with a 27.9-in barrel.

Under these conditions, the lighter projectile should certainly have higher

muzzle velocity, regardless of caliber.

 

[mrbigtexan]

I believe barrel length and expansion ratio must be considered too.

270 and 25-06 have virtually identical powder weights, so to compare

apples to apples, they must also be given virtually identical barrel volumes,

so that the burn expands into a virtually identical volume and performs

a virtually identical amount of work on the projectiles.

A quick calculation shows that the 25-06 barrel should be 1.162 times

as long as the 270 barrel. So, for example, a 24-in 270 barrel would yield

the same expansion ratio as a 25-06 with a 27.9-in barrel.

Under these conditions, the lighter projectile should certainly have higher

muzzle velocity, regardless of caliber.

I see the reasoning in this

 

[mrbigtexan]

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.

I have them both and i really like them both, but i have a special purpose for both as they really do kinda overlap

 

[mrbigtexan]

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.

I agree 100 percent

 

[elkaholic]

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.

Basically, what you are saying is true. B.C. is based on SD plus bullet shape so anytime you lower the sd (by using a higher proportion of lighter metal) you also affect b.c..............Rich