Been waiting for one since 1983 when I bought my 25/06...

Any ballistic engineer(s) want to tackle the pros/cons of such an offering?

There is plenty of horsepower to drive it.... no, it wouldn't beat a Weatherby in velocity...

Most 25-06s are twisted 1/10. A 130 gr bullet would most likely need a faster twist to stabilize, except maybe a roundnose.

Yep, not enough twist and God knows the makers are slow to change twist, pun intended.

It is not necessary. Anything you would hunt with a 130gn bullet can be taken by a flatter shooting 115gn - 120gn and most likely a plain old 100gn.

JW

What about Chupacabra?

Gee, replies so far are interesting but a little short on a some engineering references...

As in, how do all the [heavier] 6.5, 7mm, 30 and even larger caliber bullets work in a 1x10 twist? Can you cite a controlling formula...?

An engineer, is there an engineer in the house?

They don't.

Generally speaking, 1/8 handles the long 6.5mm, 1/9 handles the long 7mm. 1/9 handles the long 30s.

It would suffer in sales to the 270 comparison, right or wrong....

Hodgdon Powder Company Manual #27

270 Waetherby Mag, 1X12 twist, page 132
30/40 Krag, 1x10, page 174
7MM STW, 1x10, p. 166
300 Win. Mag, 1x10, p.203


Looks like you were NOT a ballistics engineer in the marines...

I don't think Hodgdon has loads for what MM would consider "long".

Sierra, probably, with a twist spec.....

Oh I see, you're a smart guy.

I was an Arty/Naval Gunfire FO.

Get yourself a 1/10 7mm and go have fun with some 180 VLDs, or a 1/10 308 and some 240 SMKs, or a 1/10 260 with 140 VLDs. Be sure and get back to us on the results.

I think Montana knows how to call in rounds from 16" guns to drop on a nats azz.

Seems the 270 has 130 grain covered pretty nicely. Not sure how much market there would be for a harder recoiling 25-06 that offered nothing the 270 didn't already do just fine.

DJ

Looks like you didn't win any " Keyboard Commando" Spelling Bees....


Ingwe

A lot of Euro made stuff sported slower twists...like Waetherby's (grins)

My gunsmith has a 1-16 222 Sako; he wanted BT's and had to run 40's to get them to spin.

I read Ken Waters had a hell of a time with 200gr. bullets and a 300 Mag of some Euro sort. He found out it was twisted 1-12.

Alas....

Mr. Montana Marine et al:

Read the original post, a 130 grain bullet in 25 caliber; I will now qualify it as a 130 grain "hunting" bullet and not a VLD.

Not trying to be a smart guy, just trying to gain an answer with my preferred level of credibility.... looks like you guys don't 'really" know.

Despite your illustrious artillery experience, I see no formula, nor a reference to a ballistics engineering degree (perhaps you have one) So, I guess I will call Sierra someday....

Radical thought and concept....


Ingwe

Does the "hunting" bullet have a plastic tip or a BT, or is it a semi-spitzer RN?

Lotsa folks might want a 175 gr. Ballistic Tip for hunting, but Nosler found your 1-10 not to work very well....

Kinda like a 130/1-10/25-06, depending on bullet shape, might not work very well. It sure won't sell in a semi-spitzer....

You can go Greenhill formula, but its subject to more than what it takes into consideration....

Credibility comes only from a degree in your world?

From what I've seen, MM has a post-grad in this stuff from experience if not from an institution of higher learning.

For what its worth (I don't have a degree in communications, so maybe my experience won't suffice) I have emailed Sierra and found them very responsive.

I'd like to hear if their explaination is substantively different from that of MM. I have a feeling... and while you're at it check and see what sorts of degrees those guys have. You never know what sort of BS they're shoveling (or not shoveling... pun intended).

Good post efw....


Thanks..


Ingwe

Experience outside paper calcs helps...

I do believe Shane has that in spades.

Shane has a LOT of trigger time...


Ingwe

There are getting to be more and more VLD-esque hunting bullets out there. Scirroco, Berger, Accubond to name a few.

A 130gr roundnose out of a 1/10 twist 25-06 might work, but what's the point? If you are thinking anything with a pointed end, and maybe a boat tail, you will need more twist.

Call Sierra, that's a good idea. I've called them a couple of times over the years and they have always been helpful. One time they even did a underground tunnel 200-yard test to answer a question for me pertaining to stability of a 190 SMK out of a 308 twisted 1/12.

It's for the same reason you don't see any 160 gr. BTSP's in .270. Nosler does make a very nice 160 gr. Partition, but notice the shape? And guess what that bullet's market share is.....

I honestly don't know why I even bothered typing that. It was an utter waste of time, as are these few words.

Do mind your remarks about OUR service men, smarA$$ or otherwise.

Since I am no engineer, here is a link for twist rate. http://www.realguns.com/calculators/riflingtwist.html

A 130 .257 is going to have to be 1.5 or so inches and I am doubting you can get much more than 2850. That puts the twist requirement at 1 in 7.9. Which is really close to my 260 with a 1 in 8 twist running 140s.

Play with a 100 or 110 with that calculator and you start seeing the twist rates that are offered by manufacturers.

Exactamundo!..You don't need a degree in Rocket Surgery to know the BC on that one would turn it into a rainbow trajectory sooner than you had wished...


Ingwe

FWIW I shot a few 125gr. Extended Range Remingtons IIRC at some hogs...
Don't recall the BC, but if they coulda made 'em 130 they woulda for THEIR 1-10 twisted rifles......

David, excellent post!

The guys at Sierra who helped me out were not what I'd call pencil pushers. They seemed to me like shooting/hunting enthusiasts (I dare say loony's).

When I called about stability of the 190s in a 1/12 308 Win, the guy got back to me in a couple days. He made up a deliberately slow load, about 2000 fps, and checked it in their underground facility in one of those machine-looking contraptions. Load shot 1/2" at 200 yards. I got the feeling those guys truly enjoyed that sort of stuff.

http://www.sierrabullets.com/index.cfm?section=techservice&page=ballistictech

I only wish to add that Shane has kept remarkably cool through the course of this thread. Well done!

Shane is a cool dude!

Ingwe

It takes a fair amount to get me worked up.

Good on ya'

As you can see, it just takes someone flipping schitt to one of the good guys to get me worked up...


Ingwe

I think in their last manual they posted an on target velocity schematic of such a load for B.C. testing at 200yds, with twist a consideration...

Yeah, Shane stayed cooler than I for sure. Don't knock on the boys in uniform, or even make comments that might be taken that way. That I can't tolerate. We here in Bama might be hicks, but we stand with our soldiers. Dont think I've ever engaged in conversation with Shane on this board, but he has my respect for his service, if for no other reason.

Shane,

That comment was made in a state of light "rage", you might say. The boys at Sierra have to be shooters to turn out the great products that they do. I feel the same about pretty much all bullet mfgs. I deal with engineers, structural, every day. Some are genuine pencil pushers, others have been there, done that. There is a huge difference in the two. Thanks.

David

Sierra also has a very good twist-calculation calculator (much more sophisticated than Greenhill) in their ballistics program.

I just ran a .25 130 Ballistic Tip (theoretical bullet, based on the length of a 115 BT multipled by the 130/115 weight factor) through the Sierra calculator, at a muzzle velocity of 3000, which might be a little generous. The answer was a 1-8" twist. This agrees entirely with what Shane said, which is not surprising.

Our new "friend" Buckeyespecial could also have obtained Sierra's ballistic program and used it to search for the result himself, but instead chose to ask his question on an open forum and then sarcastically question the answers he got, without having a clue about the backgrounds of anybody who was answering. I am also gratified that everybody else pretty much kept their cool in the face of such blunt rudeness.

Unfortunately I don't share Shane's coolness, so you can shove a 130 bullet right up your ass [bleep].

Way to go Steely! Now I wish I had left my first post up. I ain't about to retype it. I ain't that mad anymore. Shane's cool, so I'm cool.

They seem to be working overtime at the tool factory of late, fortunately the ability to make a sharp one has eluded them thus far.

Most of us post up to seek or share info/comraderie. Some post only really looking for a good ol' pissin' match.

I've 'gone there' a time or two, but it's not really my thing. Entertaining to read sometimes.

Not that I feel compelled to answer [bleep]'s post, but here is a picture of some 25 caliber bullets.



The picture shows bullets that I have loaded for in .25-06. The two bullets to the far right were made by Wildcat Bullets. The second from right is 125g ULD and far right, 130g bonded bullet. As you can see with the bonded bullets, they are quite long.

In my 1:10 twisted barrel, they didnt shoot well. Not sure if a coincidence or a twist issue. No keyholing though.

So to answer your question, Wildcat Bullets did make a 130g bullet. With new ownership, not sure if they still are.

and as we like to say in WI....WTF's a Buckeye.

The one thing that hasn't been mentioned so far regarding twist, and why slower twists work better in larger calibers is because twist affects the surface speed. If you spin a .35 caliber bullet in a 1:10 at the same velocity as a .25 caliber through a 1:10, the outside diameter of the .35 will be spinning much faster than the .25 The center of the bullet will be spinning at the same rpm, but not the outside of the bullet.
So that's why it takes such a fast twist in .22 calibers to stabilize bullets with a lower sectional density, length, or BC than a .25 cal of the same weight.
Make sense?
And, no I'm not a ballistic engineer. If I was, then the term for "outside diameter speed" would have come to me, but it didn't.

If you need a 130 gr for a 25-06 just buy a 270

You are mixing angular and linear quantities here.

I know, help me out with the terminology. But the idea is correct right? Larger diameter bullets need less twist than little bullets, which is why a .22 needs a 1:7 for long match bullets and .26 needs a 1:8 for even longer match bullets, and a .338 does fine with a 1:10 with 300 grain match bullets.
Right?

Sums it up quite well. Guy deserves a in person, back of the neck held, face in the dirt.....held long.

At least he serve(d)........

angular velocity

Outside of a larger diameter bullet has farther to travel to get all the way around. Since the rotational velocity is the same given the same twist and the same linear velocity, the larger diameter bullet has a higher angular velocity.

What I don't know is what that has to do with stability.

Fast Ed

No. Angular velocity is the measure of the speed of rotation about the axis.

At the same angular (rotational) velocity a larger diameter bullet has a higher surface speed .

Larger diameter bullets have higher axial moments of inertia which contributes to their stability, lessening the required twist.

Do a google search on "greenhill formula".

The twist rate depends on the length of the bullet, not its weight. You can shoot 130 grain+ bullets with a 1:10 twist in larger calibers because since the bullet is larger in diameter, it doesn't have to be as long for a given weight.

To add to what natman said, an increase in diameter does not increase the volumn in a linear pattern. So the weight/length ratio changes as the diameter increases. As bullets get larger in diameter, the length of bullet to gain, say, 10gr., actually decreases. EX: hypothectically let's say a 7mm(.284") bullet takes a length increase of .005". A .458" bullet may only take .001" to increase 10gr. in weight. But the change is not linear. You can't say it takes "X" increase in length per "Y" change in diameter. Hope that makes sense. Circles don't work like squares, basically.

David

For the cylindrical part of the bullet it's easy. For a cylinder of radius r and length l we have

volume = pi * r^2 * l

So volume, hence mass, grows linearly with length and quadratically with radius.

I stand corrected. Been a lot of years since my college physics days.

Fast Ed

"volume = pi * r^2 * l"

What he said! I think??? Too many years since I used these equations.

If you want to shoot 130-140 grain bullets in your 25-06, just take the rifle in to your gunsmith and have him put his barrel wrench on the muzzle and give it an extra turn to tighten the twist.



Bruce John Doe