I'm loading for a 280 Remington with 139 grain Hornady SST's and BTSP's. OAL with the bullet just off the lands with both bullets is in excess of 3.40". With the BTSP's, more than half the bullet from the cannelure to the beginning of the boattail is exposed, leaving only 2mm to 3mm to be held by neck tension. The SST's are a little better, but not much. Is this enough to assure adequate grip and minimize run-out? This gun appears to have been set up for heavier bullets, but I'd like to see if 139/140's will shoot. Thanks!

The minimum measurement I use is a tenth of an inch(bullet seating into case) with .003 neck tension.This is with factory guns trying to chase the rifling.Have had no problems and run-out depends on your necks & die set-up.-Jeff

You can also try using flat base bullets to get closer to the rifling.-Jeff

A general rule of thumb that I have used for years as a starting point is to seat the bullet "caliber deep", ie .224" for 22cal, .308" for 30cal, etc.

Depending on how I'm going to use the loaded round I've gone as low as 1/2 caliber into the neck but that's only for single-shot rifles.

Bolt-action repeaters get a minimum of 3/4 caliber into the neck but I feel more comfortable with a full caliber seating.

I agree with Craigster. One caliber. If using boattails it should be not counting the boattails section but wher the base actually is full width. This is standard practice but not written in stone.

Have fun

Hcliff

What I have decided is this. I would rather seat .25" deep and jump .15", than seat .1" deep and not jump. The deep seated loads are just more consistent.

In my experience, the "seat as close to the lands as possible" advise is given too much weight, especially for hunting loads. JMO, Dutch.

The REAL answer is "Ask your rifle."

Some rifles need a bullet seated way out -- my 6.5X55 Kimber-sporterized M96 Mauser is a good example -- with Hornady 140 grain bullets I have more bullet showing from the case mouth to the cannelure than I do inside the case.

My Kimber .22 Hornet is another example -- it likes the bullet actually in the lands.

Other rifles shoot better with the bullet seated deeper.

There are three questions to ask:

1. How well does it shoot?

2. Will it feed through the magazine?

3. Will the loaded round withstand normal handling?

If it shoots well, feeds through the magazine, and doesn't come apart in your pocket, you have a good load.

Being new (1 yr) into reloading what I seem to have read everywhere is a minimum of one caliber.
What is this based on? Is there any inherent risk / danger in seating out further? I could use a little more length on some of my rounds but have this 'one caliber rule' burned into my brain and this is the first (for me) that I have seen or heard folks recommend less than that. One tenth of an inch (.100") is that really ok?

I've come to this board in 'sponge mode' and am trying to re-visit the very basics of everything. One of my favorite quotes is "How can you know all the answers, when you don't even know all the questions". So I've put my pride away and will continue to try and learn / ask questions of those that have more, better or just different perspectives than my own even if it means asking the most basic of questions. Sure I learn from folks at the range and by reading but this type of exchange is top notch stuff. I mentioned this on a different post and I'll say it again. Being new to this board (and 47 years long in the tooth) I REALLY admire the fact that folks go out of their collective way to answer, maybe the same old question, in a polite, informative and sincere fashion. I've found a new home here and thanks for having me over.
XWind

In some rifles, if the bullet is seated to far and it kisses the lands it can sometimes (not always)cause excessive chamber pressure. I had a Ruger 77 in 223 that blackened the primers when the bullets were seated touching the lands. If the round will fit in the magazine and there's not enough contact and/or tension between the bullet and the case mouth, the bullets can sometimes pull out due to recoil. If you're in the single shot mode this obviously does not apply. FWIW.

Forgot to mention, the "one caliber rule" is just a suggested starting point. I've gone both ways with seating, it's trial and error. Experiment and find out what safely works best for you.

Old Dog,
I have one rifle that I cannot seat the bullet out to even close to the lands. I own a vintage Remington made 03A3 Springfield that has been sporterized and fitted with all the neat stuff BUT the lead is so long that a 180 grain bullet will just touch the lands when it barely meets the case. The chamber is perfect, headspace is near minimum and it shoots as good as any of my weapons - sub-MOA groups.
My point is that it doesn't seem to matter that the bullet jumps into the rifling . . . they jump accurayely enough to keep good groups.

PaulS