I'm constantly--and, usually, unsuccessfully--trying to find out bullet lengths from various manufacturers. Barnes, for example, will give them to you if you call or email Ty Herring at their plant. Others seem to have no clue.

I want it because I'm going to buy or build a shortened mountain rifle (e.g., Rem Model 7). For the bores I'm interested in (6.5 & 7mm), I'd tend to like the heavier bullets. I use the Greenhill Formula to determine optimal twist rate for a selected bullet length. High SD bullets like Barnes are loooooong.

Well, I finally came across a catalog that publishes their bullets' lengths: Woodleigh out of Australia. Their bullets look pretty darn nice, too.

It'd sure be nice if a gun website, like Steve's Pages, would act as a repository for bullet lengths. Is there something like that on the WWW?

This is always a problem when desiring a heavy for caliber bullet.

My suggestion is one of the older military actions that used a heavy bullet when first introduced. As an example, have a Brazilian Mauser Mod 1908 that originally was a 7mm Mauser chamber. Had it rebarreled (original barrel was getting pretty dark) with a fast twist barrel and rechambered for 7mm Mauser Ack Imp. The 162 bullets stabilized beautifully in it at a high velocity.

Another is a 1941 Husquarvna Swedish Mauser originally in 6.5x55mm. Again, rebarreled and rechambered for 6.5x257 Ack Imp.

A standard Ruger M77 action was rebarreled and chambered to 7mm Dakota. 175 gr bullets work great in it.

All these allow ample magazine length to accomodate the longer bullets and not crowd the case capacity of the round. You need to work with the gunsmith and let him know you want extra throat, or leade, for the longer bullet. I normally make up a dummy round with the bullet preferred and take that to the 'smith along with the action to let him custom chamber for it.

Thanks, kdub. I'm also thinking hard about just buying a factory gun. My original desire was to build a custom 260 Rem. mountain rifle. I do, though, like the Win M70 Compact a lot (in 7mm-08), and I had to stop & ask myself "Why spend $2,000 for a .264 vs. .284?" Fair question, I figured. I can't remember off the top of my head what the 7mm-08 is twisted at, but I'm mainly interested in 160-175 .284" bullet weights. So, I'll have to see how that twist rate stacks up against those bullets (Barnes, Woodleigh, Swift A-frames, etc.).

Swift bullets publishes their bullet lengths in their loading manual.

Swift bullets publishes their bullet lengths in their loading manual.One of the few I don't own! Thanks.

Not to be critical, but I think that you are putting entirely too much work into this.

First - the Greener formula, while a useful approximation, is not the end-all and be-all. It was a very handy rule of thumb in it's day. But.... stricly by the formula.... you can find all sorts of bullets that shouldn't work, but do anyway, and possibly some that should, and don't. Keep in mind that the old boy didn't have a computer, and even 2,000fps was unheard of in his day, much less the 3,000 - 4,000fps that some cartridges can get today. He could not have forseen plastic tips, boattails, et al.....

If you want to nail down the twist rate before you get started, then just ask the bullet manufacturer what is known to work, with their bullets, in the velocity range that you anticipate.

Other than a few odd choices ... most rifle bullets will work in the most common twist rates, for hunting (over .22) calibers. This should not be too surprising; after all it would not be in the bullet manufacturer's interest to be making bullets that don't work! If one particular bullet requires a fast (or non-standard) twist, then quite often it'll say so right on the box.

The rifle manufacturers put a fast-enough twist rate on their barrels so that the great majority of bullets will in fact work properly. Too fast of a twist is always preferrable to too-slow of a twist.

If you are going to build a sporter, for a commercial cartridge, using commercially-available hunting bullets, then select a twist rate that the rest of the herd uses. Doesn't sound like a real scientific method, but - hey - it works. And it's more likely to predict success than the Greener formula, when you get to the outer fringes of bullet weights, I'll wager.

If you're going the custom barrel route, I'd verify what the bullet manufacturer said, against what the barrel manufacturer says. After all, it is in their interest to see their product work well.

If there is any discrepancy, go with the faster of the two choices, and sleep well.

Like kdub said, then the only other thing to do to achieve perfection is throat the barrel for the exact bullet you'd like to use.

Here's an up-to-date set of calculations for bullet stability. The Greenhill (not Greener) formula was a simplification in it's day (1879).
http://www.eskimo.com/~jbm/calculations/drag/drag.html

Bye
Jack