Seating depth for start of load development
- Thread starter craig6547
- Start date
Magazine length.....anything longer I wind up swearing at trying to load.
Keith Glasscock
Gold $$ Contributor
If magazine length permits, I try to start at .020" jump for a hunting rifle.
stool
get specific.
what gun
what caliber
what distance do you hunt at.
generic questions get generic answers...which are kind of useless...
what gun
what caliber
what distance do you hunt at.
generic questions get generic answers...which are kind of useless...
craig6547 said:
hogpatrol
Silver $$ Contributor
craig6547 said:
For me, it doesn't make any difference which caliber or which discipline. For spitzer bullets, I start at .005 off the lands, VLDs, +.010, load .3gr apart, 3 or 4 rds., chrono everything and use the testing method explained in the long range thread in this forum.
http://forum.accurateshooter.com/index.php?topic=3814361.0
Two or three trips to the range and I usually have what I need. Good Luck!
stool
while .3 is a good step for a 223, it is too big for a 221 fireball,and pretty insignificant for a 300 win mag.
hogpatrol said:
for the intended use, it does not make a bit of difference the cal, action bbl, bullet, etc. in my opinion,
I always start with .020" jump and never let it get closer than .010jump, to be sure of extraction of an unfired round.
This has worked for me for nearly a 100 rifles of dozens of calibers from 221, to 300wm, in Rem, Ruger, Win, actions.
just be sure to watch the magazine max length.
Bob
I always start with .020" jump and never let it get closer than .010jump, to be sure of extraction of an unfired round.
This has worked for me for nearly a 100 rifles of dozens of calibers from 221, to 300wm, in Rem, Ruger, Win, actions.
just be sure to watch the magazine max length.
Bob
If magazine and bullet length permits I start at 10 thousands off the lands. If I can't get the accuracy I want by adjusting powder and primer I will move the bullet further away. I never load a hunting round closer than 10 thousands. I learned my lesson years ago by sticking a bullet in the bore when I went to unload my rifle when getting out of a tree stand. I had to waste half a day going after a cleaning rod to poke the bullet out and clean all the powder out of the action.
All the above is great advise - unless one shoots monolithic bullets (ie copper, Fail Safe, Swift anything, etc). For me these shoot best with a good sized jump - .050-.090". My brothers Winchester Featherweight likes them jumped 0.200"! What with the extra long bullets pushed well into the cases powder choices become interesting. Terminal performance is outstanding though and you can use lighter bullets than what you might be used to as they lose essentially zero weight upon impact. Personally never had any Triple-Shock break up.
For those that say "make sure your hunting rounds will fit the magazine", just how many rounds do you shoot to take down your animal. Out here if you miss with your first round the deer or elk just runs off and you don't get a second shot.
Load for the best accuracy, chamber the round, lock the safety and go hunting. If you want to shoot your rifle as a repeater, just load some ammo that will fit the internal magazine and save it for the "camp target shooting".
Load for the best accuracy, chamber the round, lock the safety and go hunting. If you want to shoot your rifle as a repeater, just load some ammo that will fit the internal magazine and save it for the "camp target shooting".
Raythemanroe
Bullet Whisperer
I start at .005 off
Ray
Ray
BoydAllen
Gold $$ Contributor
One thing that fouls loaders up is that they don't understand that just like powder charge has "nodes" at intervals, so does seating depth. In the past, I would make a small change in some particular direction, in or out, and if the groups got bigger, I would falsely conclude that further movement in that direction was a waste of time. What I understand is that more testing is required by continuing to make small changes, testing with small numbers of shots, until enough change has accumulated to possibly get to a seating depth node, or from the one that I am at to the next one in either direction. I think that this is a matter of bullet timing to the muzzle, although I have no way to make a calculation to shorten the process. Generally, for my varmint and target rifles, I seat into the lands, but not at full jam, perhaps .006 to .010 longer than touch, measured with a gauge. The exception would be if I am helping a friend work up a load where there is a magazine length issue, or he is using Barnes bullets. Another issue is that if you go from seating at touch or into the rifling, to jumping, and do not do some powder charge exploraton, the reduction in peak pressure could be throwing your results off. In reloading manuals that I have read, the same charge and bullet will give 5-6,000 CUP less pressure than the same combination with the bullet seated to touch or into the rifling. This would be equivalent to a significant change in powder charge.
While there are always exceptions, as a general rule we know that certain bullet types like certain jumps and jams.
If I want to shoot a vld, I start out jammed .010. If it's a hunting rifle and I'm shooting Barnes, I start out jumped .020.
Then you can expirement from there. Like Butch says, if you are trying to find a max safe charge, i start jammed .010, (and keep air temp in mind) just to make sure I really do have that max safe charge.
If I want to shoot a vld, I start out jammed .010. If it's a hunting rifle and I'm shooting Barnes, I start out jumped .020.
Then you can expirement from there. Like Butch says, if you are trying to find a max safe charge, i start jammed .010, (and keep air temp in mind) just to make sure I really do have that max safe charge.
For most hunting I'm with the posters here an would recommend staying at Mag-length for fast follow-up shots. I've known a few hunters that wanted
to single load for various reasons, so that choice is up to you.
That said, pick the shorted over-all length for doing powder pressure testing. I would recommend the book/published values for OAL of your cartridge and bullet to start. If you have room to seat longer either still within Mag/Length or for single loading then adding length to the cartridge will reduce the pressure meaning moving further toward the safe side. There are plenty of threads on how to measure to the lands for jump distance, but each bullet has a sweet spot and frankly quite a few are right at the published OAL, but it really depends on your specific rifle.
Once you reach the length where the bullet is touching to jammed into the lands the pressure goes back up, so tread carefully.
Doing this in reverse is very ill advised.
-Mac
to single load for various reasons, so that choice is up to you.
That said, pick the shorted over-all length for doing powder pressure testing. I would recommend the book/published values for OAL of your cartridge and bullet to start. If you have room to seat longer either still within Mag/Length or for single loading then adding length to the cartridge will reduce the pressure meaning moving further toward the safe side. There are plenty of threads on how to measure to the lands for jump distance, but each bullet has a sweet spot and frankly quite a few are right at the published OAL, but it really depends on your specific rifle.
Once you reach the length where the bullet is touching to jammed into the lands the pressure goes back up, so tread carefully.
Doing this in reverse is very ill advised.
-Mac
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.