I have always full length sized brass for bolt action,but will start neck sizing only to keep from working brass so hard. These reloads will be rifle specific. My question is what is the best method to determine optimum bullet seating depth for that rifle. Thanks for any help.
Accuracy
- Thread starter rpchevy02
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redneck2
Member
Do you have a way to measure the distance off the lands?
BearW
Member
I measured off the lands for my 300 win mag and backed bullet off a hair
BearW
Member
I did mine sort of redneck I guess for my 300 win mag. I used a piece of brass that I removed some material out of the throat just enough for bullet to be pushed in when chambered but still tight enough to not get stuck in barrel when bolt pulled back. Did this a couple times to make sure I got consistent numbers. Piece of brass was ruined in process Don't know if it is scientific enough for some but it's a tack driving sob. Don't know if I explained that well enough....
Driftertank
Member
My FIL has an old Nosler book that says to use a fired case, place an example of the bullet you plan to use in the case mouth, crimp it ever so gently in place with a pair of pliers, then place the round in your action and slowly, gently close the bolt, slowly extract it, and measure OAL with a dial caliper. Repeat a few times to ensure consistency. This provides your OAL to the lands. The book then says to reduce that length by about .015-.030"
Did this with my Rem 700 LR in 7mm, and got an OAL of 3.383" to the lands with Hornady 154 SST. Made up some ladders with OAL set at 3.360" and ended up with a load that gives .5-.75MOA 4rd rapid groups.
YMMV, but for me this was simple and effective.
Did this with my Rem 700 LR in 7mm, and got an OAL of 3.383" to the lands with Hornady 154 SST. Made up some ladders with OAL set at 3.360" and ended up with a load that gives .5-.75MOA 4rd rapid groups.
YMMV, but for me this was simple and effective.
BearW
Member
That explains it better than I did. But I used the same procedure in general. I do have to keep my action and barrel throat very clean otherwise bolt won't fully close. That bullet has to be right there
rcmodel
Member in memoriam
1. Seat long.
2. Color the bullet with candle soot, Magic-Marker, or Dry-Erase marker.
3. Chamber the round and note how much black the rifling rubbed off.
4. Seat slightly deeper and do it again and again until the rifling leade is no longer scraping the black off the bullet ogive.
It don't get no more precise then that, even with a $300 tool that's supposed to be more precise then that.
I got news for you, It isn't.
rc
2. Color the bullet with candle soot, Magic-Marker, or Dry-Erase marker.
3. Chamber the round and note how much black the rifling rubbed off.
4. Seat slightly deeper and do it again and again until the rifling leade is no longer scraping the black off the bullet ogive.
It don't get no more precise then that, even with a $300 tool that's supposed to be more precise then that.
I got news for you, It isn't.
rc
witchhunter
Member
It don't get more precise than that RC! I have used this method for 40 years. Once you have a zero setting, adjust the die to seat going by .002 at a time until you get the best accuracy. Change bullet? Start all over. I feel this is
more important than powder weight or ultimate accuracy.
more important than powder weight or ultimate accuracy.
Nature Boy
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If you guys were going to force rank the variables that have the greatest affect on accuracy, what would your list be?
Sport45
Member
rpchevy02 said:
Take it to the range and shoot it with test batches at varying seating depths.
I assume you've already fine tuned it for powder, charge, and bullet. Changing any of those will have more effect on accuracy than seating depth in my experience.
jgh4445
Member
Stoney Point ( or Hornady) bullet comparator. That's what they are for.
When I'm tuning a load, looking for accuracy and not concerned with mag length, I first work on the powder charge. When I've got the charge about right with good groups I then load a bunch with that charge weight - right out to touching the lands.
At the range I use my Lee hand press with a Redding micro seater die to progressively seat the bullets in 5 or 10 thou at a time - shooting 5 shot groups and watching for the groups to tighten as you approach the sweetspot - Ideally you will see the groups start to open as you go to far. Obviously watching for any pressure signs along the way.
With some bullets/barrels there a real difference with just a few thou. My accurate rifles are single loaders so not concerned with mag length.
At the range I use my Lee hand press with a Redding micro seater die to progressively seat the bullets in 5 or 10 thou at a time - shooting 5 shot groups and watching for the groups to tighten as you approach the sweetspot - Ideally you will see the groups start to open as you go to far. Obviously watching for any pressure signs along the way.
With some bullets/barrels there a real difference with just a few thou. My accurate rifles are single loaders so not concerned with mag length.
ironworkerwill
Member
1, The shooter( my rifle don't shoot worth a flip, whats wrong with it?)
2, The equipment( no one I know can shoot this pos worth a flip{also see #1})
3, Component selection( I can't make these 145grain vld bullets group outa my 22-250)
A, Insure components match equipment
.........This could take a while, might ought to spawn a new thread.
gamestalker
member
I seat long, then in small increments I seat deeper and deeper until the cartridge just barely sticks to the lands with the barrel pointed straight up, yet drop out with a light tap. I call this zero, though it's probably .005" longer than zero. Then I increase the OAL by .010", perform my work up, and adjust shorter until best accuracy is obtained.
For me, I've found my most accurate is when the bullet is either just contacting the lands, or slightly jammed.
If I'm forming brass, I always jam them. This keeps the case head firm against the bolt face, thus assuring that the shoulders get pushed out completely during fire forming.
I almost always use a FL die these days though. When properly adjusted, I can get about as many loads from my brass with a FL die, as I can with a neck die.
GS
For me, I've found my most accurate is when the bullet is either just contacting the lands, or slightly jammed.
If I'm forming brass, I always jam them. This keeps the case head firm against the bolt face, thus assuring that the shoulders get pushed out completely during fire forming.
I almost always use a FL die these days though. When properly adjusted, I can get about as many loads from my brass with a FL die, as I can with a neck die.
GS
Offfhand
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Why complicate something that is so simple? Some of the above described methods for determining max seating depth are far more complex and time consuming than they need be. It takes about three minutes to determine exact depth to lands using only a cleaning rod and two paper clips. Measuring calipers are also needed of course, which you need anyway. If you want to do the same thing with fancier equipment, use the Sinclair seating depth gauge, which works on same principal.
spitballer
Member
If you're lucky enough to have a bolt rifle you can seat .010" - .015" over and let the lands do the final seating. Since neck tension has a profound effect when seated into the lands I always keep the necks fairly loose (not finger loose) for consistency. It's easier to get the necks consistently loose than it is consistently tight. If you use standard brass with varying neck wall thickness you'll always ave trouble getting consistent neck tension, so either turn those necks or buy premium brass. Premium brass is well worth the money for a bolt rifle and mandatory for undersize chamber necks.
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