[carnaby]

I'm loading .300 win mag and I'm a total noob. I'm trying to get a good bullet seat depth for my rifle, but I'm curious about a couple things. For one, I seated a bullet in an empty sized clean once fired case. This case was only neck-sized, so apparently it is the right size for the rifle chamber it came from.

To find bullet seat depth, I seated the bullet sticking pretty far out, then chambered it gently and then extracted it. I took the seat depth after this, minus about 25 thou and called it good. I think this is one way I read to do this, but maybe I misread the Lee reloading manual. In any event, the overall cartridge length ends up being 3.43" or so, IIRC (I'm at work and didn't write it down), but the pamphlet that came with my Lee dies says the max OAL is 3.42". Even if my numbers are wrong, the relationship is the same as stated.

So here's my question: is the max OAL for this cartridge given such that it will fit in ANY rifle chamber of that caliber, and I can use a greater OAL if it works in my rifle, or is the stated max OAL something I should be careful never to exceed for safety and other reasons? If other, what other reasons? :confused:

Further, I compared my cartridges to factory, and mine are a fair bit longer, but my bullets are Speer Gold Match and have a pointed tip, while the factory stuff is hunting ammo with a blunt tip. I don't know how much of a difference this makes, or how you're supposed to account for it. I presume that among the important things, it's where the bullet contacts the rifling in the chamber, but I don't know what else.

[Dave P]

So here's my question: is the max OAL for this cartridge given such that it will fit in ANY rifle chamber of that caliber, ---> Yes, any rifle chamber with saami specs (which is normal)

I can use a greater OAL if it works in my rifle, ---> Yes, but try to keep the bullet off the lands so pressures do not go too high.

is the stated max OAL something I should be careful never to exceed for safety ---> Yes, if you jam the bullet, the starting pressures will be much higher.

Dave

[USSR]

So here's my question: is the max OAL for this cartridge given such that it will fit in ANY rifle chamber of that caliber, and I can use a greater OAL if it works in my rifle, or is the stated max OAL something I should be careful never to exceed for safety and other reasons?

Carnaby,

There is no "max" OAL listed for a cartridge, since it would vary from one rifle to the next depending upon the bullet used. The various reloading manuals simply list the OAL that "they" used. You can use a different OAL (within reason) without safety concerns. Just remember that using a longer OAL than what is listed in a reloading manual usually results in lower pressure/velocity, while a shorter OAL has the inverse effect.

Don

[Grumulkin]

There are several things to consider regarding overall length:

1. The cartridge must fit the magazine unless it's a single shot firearm.
2. Enough of the bullet must be in the case so that it's held securely.
3. The bullet should not quite engage the lands. Most of the time, starting off a bullet close to the lands will improve accuracy but there are exceptions to this. Some guns like Weatherbys have a lot of "freebore" so you will never be able to seat a bullet so it touches the lands but in most, you can seat it out far enough to get close to but not engaging the lands. If you seat a bullet out far enough that it actually engages the lands, the pressure will increase. Depending on how hot your loads are, a pressure increase may have unwelcome consequences.
4. If you change the length of a cartridge, you are in effect changing case volume. If the bullet is seated more deeply, the case volume is smaller and the pressure higher with the same powder charge. In larger cases like the 300 Winchester Magnum, seating a bullet a little further in or out probably won't make a whole lot of difference in this regard however.

As long as you take the above into proper consideration, it doesn't matter to what length you seat your bullets.

[carnaby]

There is no "max" OAL listed for a cartridge, since it would vary from one rifle to the next depending upon the bullet used. The various reloading manuals simply list the OAL that "they" used. You can use a different OAL (within reason) without safety concerns. Just remember that using a longer OAL than what is listed in a reloading manual usually results in lower pressure/velocity, while a shorter OAL has the inverse effect.

Thanks Don, that's what I thought, my loads should be fine then. I just got confused becasue the pamphlet I got with my Lee dies specifically says "Maximum Cartridge Length 3.xx".

[Outlaws]

I think its also important to note that the pointy tip isn't what should be a concern. Its where the bullet actually starts to taper off into the tip that really affects how it will fit. I think if you measure your pointy ammo compared to the flat tip stuff from the factory that you used in reference, that where it starts to taper will be about the same length.

[Bullet]

Here are a couple links you might find interesting -

http://www.benchrest.com/forums/showthread.php?t=28867

http://www.benchrest.com/forums/showthread.php?t=27109&page=1&pp=15&highlight=seating+depth

[Smokey Joe]

Carnaby--Grumulkin covered the whole subject nicely, except I would add that yr proper OAL will change for each different bullet you load. Each bullet curves a little differently, and has a different shaped point, so the "right" OAL for yr rifle is only "right" with that one model of bullet--You have to go throught the whole load development process, including OAL, if you change bullets.