Factory ammo bullet seating depths

[Goofycat]

I have just completed reloading a few rounds with different powder charges so as to check pressures for the new .270 Nosler 150 grain Partions before loading the remaining cartridges. After seating the Noslers .020' off the lands, I compared my bullet seating depths with a stray factory cartridge and found that the factory bullet was seated over .200' inches more than my own reloaded rounds. I could see the factory rounds being a bit shorter than my own rounds, but a fifth of an inch? Is there something they know that I don't or are their seating depths,hence, a much shorter OAL) due to their fear of lawsuits, or what? All I know is that my bullets are seated much farther out than is the factory OAL, measured to the ogive. So, will seating the bullets at only .020' give me hugely excessive CUP, compared to factory ammmo? What the H*** is going on here?

 

[fdshuster]

Barry: Welcome to the world of 'one-size-fits-all'. They must make their factory ammo so it will fit, and be safe to fire in the thousands of rifles out there, all chambered for the same round. Not only is that dimension based on throat depth, but also magazine 'length'. As an example: the AR-15 at 2.260', so the factory ammo must be approx. 2.250'. If you have a 223 rifle with a deep throat, that's your problem, not theirs. As far as pressure differences: who can say, as the amount and type of powder used, by the factory and reloader would be very important. Following the loading manuals recommendations generally take care of that problem. I cannot remember the last time I bought center-fire factory ammunition, and I fire 3K to 5K rounds per year.

 

[Goofycat]

FD, I can certainly understand the bullet boys wanting to make sure their products are safe, but an entire fifth of an inch for a bullet to jump before it even touches lands is absurd. My measurements were done in a rifle that has not seen probably any more than 50 or 60 shots run through it, and the bullet jump would be even more in a rifle with some erosion or with a deep-throated chamber. One consolation is that I can pretend that the bullets are for 6mm BR, because that is what they almost look like. Who knows; maybe the accuracy will be incredible. Or....maybe my Remington 700 Mountain Rifle is known for long throats.

 

[PaperSniper999]

'FD, I can certainly understand the bullet boys wanting to make sure their products are safe, but an entire fifth of an inch for a bullet to jump before it even touches lands is absurd............'

But it's only that much is YOUR rifle. Other rifles probably have less of a jump. Like the posts above, the factory ammo people have,supposedly) done their researched and figured that seating depth still provides a 'safe margin' for ALL rifles in which it could be chambered.

I have seen similar results, although I admit .2 inch is a LOT! Your rifle must have a deeper than typical throat I'd guess?