What's the thumbrule for seating depth when you can't get close to the lands?
What's the thumbrules or guidance on bullet seating depth when you can't get close to the lands? Seems like I recall a guide line of 1/10th of the diameter or bullet length? I can't remember clearly. I have some Nosler 55 and 70 gr BT's, for the .243. They don't publish a recommended COAL for these. I doubt I'll be able to get close to the lands. Same thing happened with the Sierra 70 MK's. I seated to their recommended COAL.
General rule of thumb is 1 caliber depth into case so a 30 cal =.308. This would be in addition to any BT taper so .308" + taper.
P. S. Note: Just be aware about neck tension, COAL and Jam. One could possibly end up seating bullets that, with poor neck tension, could leave the bullet in the lands and dump powder everywhere, if one has to unload, a real MESS.
Last edited by skypilot; 06-28-2012 at 10:17 AM. Reason: P. S.
I have always used this guideline too. I generally use heavy for caliber bullets though so I just seat them to work through the magazine. I suspect a call to the bullet maker would get you a recommended seating depth also.Originally Posted by skypilot
Bob
It's better to shoot for the moon and hit the fencepost than to shoot for the fencepost and hit the ground!
I usually begin at 30 thousands from the lands. I'm not the "jam 'em at the lands" kind of guy as I think overpressure can get you when you start there. If 30 thousands doesn't work well, I will go to 20, then 15 then 10 then 5. If that doesn't work, I will switch bullets or powders.
The exception for me is the .223. That caliber seems to like 'em at the SAMI COAL for some reason. Mostly because you can't reach the lands except with heavier (longer) bullets. But even with those, SAMI lengths seem to work just fine.
Where it shoots best.
From my experince, you may find a few diferent seating depth spots where the rifle shoots its best. You may find that it shooots best at .085 off or more. I dont subsribe to the mimum one caliber seating depth therory.
beartooth91,
My reloding manuals generally recommend starting the seating depth about .020 - .030 off the lands. If you are not happy with groups at that seating depth you can seat the bullet a little longer in incremennts of about .005" as davemuzz and others do. Eventually you will discover the "sweet spot" for that particular load. Then you can try seating depths +/- .001" to fine tune the load.
Like davemuzz and I suspect, many other loaders, I am a bit uncomfortable seating bullets so they are touching the lands. Doing that is counter-intuitive to me. However, many handloaders load that way and many win competitions with the bullet started at the lands.
skypilot mentions one of the very important drawbacks of seating into the lands.
Approach long seating depths with appropriate caution.
Good luck
Most if not all of my chambers are "short throated" so I "start off" jammed into the lands when I work up loads.
I have had a couple of long throated 6BR chambers that I couldn't reach the lands with lighter bullets so I just seated the bullets in the case neck to where I thought they looked good. Was "really" surprised at the accuracy. And I didn't have to worry about pulled bullets and powder in the action if I had to unload a loaded round.
I make a dummy bullet - fired brass w/ neck tight enough to keep a new bullet in place long enough to get a chamber measurement - and start .050 (+ 0r -) off lands. SOmeone here at Savage Shooters told me to use at least one bullet diameter in the brass. I've used these methods ever since. If a .050 set back works - I leave it alone. If grouping has room for improvement - I move .005" in at a time, till it's happy.
I've been giving thought to trying some Berger VLD's. The mfg. mentions to start with the bullet jammed. What do you do if you have a very long throated .270 that won't let that happen? Anyone know if it's mandatory to use Bergers jammed? Or are they suitable for use with a set back of .020" - .030"?
Gotta Dr. Appointment- I wonder if my obama-care is in effect yet?....
Later y'all
Frank in Fla
'Scuse me while I whip this out...!
you could use of binary alogorithm
start at the largest gap and then we reduce by half each time.
Once uc accuracy improve, make adjustments
Frank, political discussion is faux pas
newbie from gr, mi.
Thanks for all the replies. I generally start off at 0.010 back from the lands....when the bullet is long enough. Even there, I'm a bit uncomfortable, worrying about pressure. But, lots of knowledgable people swear by touching the lands - Richard Lee, Sinclair (Precision Reloading and Shooting), etc.
Starting just touching the lands, not jammed but no jump, and then working up a load until you find pressure eliminates a coupla variables and concerns.
First, if you're running at safe pressure with the bullet touching the lands you'll be fine if you later have to seat away from them to find accuracy.
Secondly, you only have one way to go with your seating experimentation and that's seating them deeper.
Generally when I load kissing the lands and then find pressure I usually end right there because the accuracy is good and my speed is at max for that combo.
Beartooth91,
Nosler's 6th edition recommends Saami max OAL of 2.710 for both of those projectiles in 243WIN.
I believe on Long Range Hunting web site there is an article by Berger a few years ago concerning their surprise that hunters reported they were getting great groups using standard mags and therefore long jumps. Historically Berger had recommended on or very close to the lands. Based on these results I tried their 175gr VLD in my 300 Win Mag where it was necessary to go minimum .050" off the lands to fit my mag and I also tried up to .130"; all groups were < 1" at 100 yards, which is as good as I could do with the old heavy duplex 9X scope (recently replaced). Now 50 rounds are loaded for elk hunt this Fall.
Go to http://bulletin.accurateshooter.com/...g-vld-bullets/ for alternative seating depth method.
Yeah.....but is that covered by the Obama Health care law????
I'm somewhat thick headed about things.....
My old Remington 700 ADL, in .243, had a short throat. I had to seat the bullets deeper than I thought so they wouldn't jam into the lands. 25 years later, I get back into all of this, with a new .243, in a Savage M11 FHNS. I started with the Sierra 70gr MK, probably not the best to begin with. Could get nowhere near the lands, so, I seated at Sierra's recommended COAL. Tried IMR4064 and H380, rifle wouldn't group well. Bad bullet, should've tried something else. About to give up and tried some H414 with the same bullet, shot lights out. Powder charge didn't seem to matter.
I'm still trying to find out what my 7mm-08 likes, after two years. I've been seating .010 off. I got a semi-promising group with IMR4350 and the Hdy 139 SSTs. I'm going to try a charge variation of 1.3 grains with some seated at the same depth and .030 out. Its a finicky Savage, couldn't get the Nos 140 BT's to shoot, either.
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