Why not ?

[22popnsplat]

Why cant the bullet manufactures give out the dimensional data for the bullets they manufacture ? bullets of the same weight by different model or manufacture can change is dimension by quite a bit . I like to fit bullets to the case and chamber but its just a guess until you buy them.

[gunboat]

probably because bullets from the same manufacturee vary slightly from press tp press -- slight variation is dies -

[killshot44]

Some of it is for proprietary reasons, though it would be nice wouldn't it.

Here's a database with some info http://www.shootforum.com/forum/bulletdb.html

If you can make a visual comparison, this isn't bad http://www.accurateshooter.com/gear-reviews/bulletguide

[Cowboy T]

The proprietary "trade secret" angle may well be true. And if it is, it's a pretty dumb reason. Here's why.

If we're talking about diameter, I believe they do post it. They kinda have to. If we're talking about length, then there's no reason for them not to, since a micrometer or a set of calipers will answer that question very quickly. If they're talking about the dimensions of their hollow-points...well, anybody could just easily take a casting of that bullet and bingo, you know the dimensions. Wanna know the interior construction? Cut it in half and start analyzing away. Wouldn't take long with the right gear, which all bullet manufacturers are bound to have, and even some hobbyists have.

Conclusion: they should just publish the specs and be done with it. It'd help us as reloaders.

There's precedent for this, BTW. Unlike many other powder makers, Hodgdon readily publishes pressure information. This helps me as a reloader if I want to match my load's pressure to whatever hardness of lead alloy I happen to have on hand. Hence, I buy exclusively Hodgdon rifle powders.

[noylj]

Go back to square one...

Why would anyone give a flying fudge for the bullet dimensions?
COL is established by your barrel's chamber and the bullet. You can't derive anything about your barrel from bullet data and you can't determine COL with loading and trying.
As an old reloader, I just can't understand how so many handloaders can NOT know how to determine COL and appropriate charge weights without hand holding.
There is no mathematical formula to determine COL, unless you can derive one that includes your barrel (chamber and lede) and feed-ramp dimensions and the magazine and spring characteristics.
Areas where forums show me a lack of basic knowledge: COL determination, how to work up a load, proper expander dimensions for a given type of bullet and bullet diameter and the reasons to be sure the expander is proper, and establishing a proper crimp.
Take bullet, drop in barrel, establish distance from bullet tip to muzzle. Determine distance from muzzle to breech. The difference is your max COL. Somewhere shorter than this will give you rounds that fit your magazine and feed and chamber without problem. Make up a dummy or two, start at that max COL and work down until dummies fit your magazine and feed and chamber in your gun. Record this information and save the dummy rounds.
Data does not have to be bullet specific. Needs to have the same construction (jacketed or lead/plated) and weight. With lead bullets, weight needs to be within about 5 grains of the reference weight. Use data for heavier bullet if given weight not available. If you have data for a given weight but it doesn't include your powder, look for a similar powder by the same manufacturer that is faster and use that starting load (i.e., use Bullseye or Red Dot for a starting load for Green Dot or Unique).
Also check at least two sources for load data and use the LOWEST starting load.
For lead bullets, the expander should expand the case ID (not the case mouth belling, but the actual case ID where the bullet will be seated) to no smaller than 0.002" less than bullet diameter, with 0.001" being your target. Obviously, if the case ID is the same or larger than the bullet diameter, you are using the wrong expander.