Seated Bullet below Cartridge OAL

K

KnightofCydonia

New member
Hi,

I was adjusting with the bullet seating die as I like to seat off the lands for my .270 winchester. I accidentally loaded one round to ~3.244" which is well below my 3.405" max overall case length in my rifle. The 270's Cartridge OAL is 3.340", can I still shoot this underspec round and be safe without causing too much pressure? I loaded 150 gr Nosler BT into neck sized brass.
 
...can I still shoot this underspec round and be safe without causing too much pressure?
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Is the reduction in case volume significant? Does the reduction in case volume materially impact the burn characteristics of the powder? There's really no way to tell.

NHSHOOTER is correct; the only safe course of action is to pull the bullet and reseat it.
 
To assess right we would really need to know powder and how much.

you can use a kinetic hammer and tap it out a bit, I then put back to what OAL I wanted, do that at the range at times as I have a light seating press and the dies with me.

The issue is not the length short but longer and in the lands with a high end load.

Weatherby got their performance by letting bullets jump a long way.
 
You can shoot it. Contrary to the old wives tales, the further you move the bullet off the lands, the more you reduce the peak pressure when fired.
 
You loaded a round 0.096" below max listed length and you're worried about it??? :eek:

I think, in .270 Winchester, your worry is misplaced.
 
It takes time , then you'll start chasing the lands . After my first barrel change and measuring CBTO , OAL don't mean a thing . Unless your loading for a magazine feed .
 
.But don't you increase the pressure within the case as there's less space for the powder charge to combust and for the pressures to expand?
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No, That has been proven false by modern pressure barrels. Increase jump to lands always more than offsets reduction in case capacity.
 
I worried about COAL and my seating depth for years. Then one day after accidentally loading yet another .224 bullet .15 inches deeper than COAL, I impulsively checked the length of several different factory rounds. Imagine my surprise when I found that several of these brands were consistently more than 0.2 inches under any published COAL I could find in my 8 reloading manuals.

I stopped worrying about a tenth or two after that.

Now if I were loading at 100% powder charge or over, I'd probably disassemble the bullet. Just to be safe.
 
Ok, first of all you did the right thing and asked. Dumb people just jump off a cliff and think to ask as they are about to hit the rocks below.

don't you increase the pressure within the case as there's less space for the powder charge to combust and for the pressures to expand?But
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Short answer is kind of no but its not universal (very small capacity pistol cases come to mind)

The other aspect the "what a dumb questions type" are not telling you is you can compress loads and compressed loads can do funny things. Or over compress a compressed load. There be dragons.

So yes its a good question and I would happily work around you vs people that jump first and wonder why things went to hell.

Never been sorry I was safe but I sure as hell have been sorry when I was not.
 
Now if I were loading at 100% powder charge or over, I'd probably disassemble the bullet. Just to be safe.
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One gun at 100% vs another is ??????????/

I would take a look at the load, the powder, the listed PSI or Cup for that load and make a decision based on more data (including variability in the reload manuals)

And its going to shoot different so if I am trying to tack drive that is a reason to be even as I can.

If it pencils out ok and its a hunting load, maybe not but I have the kinetic with me so.......
 
The other aspect the "what a dumb questions type" are not telling you is you can compress loads and compressed loads can do funny things. Or over compress a compressed load. There be dragons.
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Without a godawful heavy crimp, that extremely overcompressed load will uncompress.
 
Another dumb question. If loading off the lands, is it general practice to load about 0.002" below where the bullet just touches the lands to avoid overpressure but maximize accuracy?
 
Another dumb question....
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they're not dumb questions. None of this is instinctive to any of us, we all started at zero and learned from there.

Mostly by reading what others have done, and then finding out whether or not it applied to our guns and ammo, and if it was at all useful, if it did.

So that's my question back to you, you said its a .270, but what .270 makes a difference. Loading match grade ammo for a minute of deer rifle is, in my opinion, a waste of time.

What kind of groups are you getting with ammo loaded to standard factory lengths? are you seeing any significant improvement if you load long, to "x" off the lands?
 
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