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  #11  
Old 04-23-2021, 12:58 PM
SharpShooter82 SharpShooter82 is offline
 
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Quote:
Originally Posted by hebes405 View Post
I usually start at .020 off and work my way in .003 at a time.
This is what I do as well.

To add to this what you are looking for is two groups of adjacent seating depths that show small groups. This is your accuracy node. From what I have read/watched video's on this method you do not "chase the lands" but only adjust the seating depth in the future by .003" to reaquire the node. You only need to find the point where your bullet touches the lands one time. There are many accuracy nodes as you seat the bullet deeper into the case, you just have to find them for your rifle.

To find where your bullet touches the lands (called Jam) load a bullet into a case prepared as normal, no primer, seat the bullet .060" - .100" long, coat the bullet with your favorite case lube, then feed slowly and gently close the bolt. Quickly open the bolt and remove the case, the bullet should remain in the case. Measure length to bullet ogive, this is your Jam length. From this dimension subtract .020" and begin loading seating bullets I decreasing depths .003" at a time.

This process will need to be done anytime you change the bullet you use since different bullets have different profiles and base to ogive measurements.

You will need to have already worked up your powder charge before doing the above.

This can also be done with firearm that are magazine fed, just start at magazine length instead of Jam length. Provided you have checked to make sure your magazine length is shorter than chamber length.

I do not know if chasing seating depth accuracy is worth it with iron sights. I might experiment with this in my M1 at a later date.

Eric

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  #12  
Old 04-23-2021, 02:30 PM
ceresco ceresco is offline
 
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Are you telling me now that the bullet knows what kind of sights are on the rifle?? I hope when you guys get this all figured out that you will move on to "bullet runout". Good Shooting. ...
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  #13  
Old 04-23-2021, 03:09 PM
lapriester lapriester is offline
 
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Altogether too much trouble to worry about unless you are going to use that 30-06 as a long range precision rifle....which I doubt, right? For a hunting or plinking rifle just load the COL at the length the reloading data recommends for the bullet loaded. Any difference in accuracy will not be enough to be worth the effort or extra work setting close seating tolerances. Keep it simple.

Pretty much every bullet is different ogive wise so don't think when you have something set for one 150gr bullet it applies to them all. Hornady bullets are a perfect example. They often have strange ogive differences between even their own bullets of the same weight.
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  #14  
Old 04-23-2021, 03:15 PM
lapriester lapriester is offline
 
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Quote:
Originally Posted by ceresco View Post
Are you telling me now that the bullet knows what kind of sights are on the rifle?? I hope when you guys get this all figured out that you will move on to "bullet runout". Good Shooting. ...
Sure they do. :-) I doubt they will get this all figured out here. Maybe it would be best to go on-line and see what the experts say

I would be skeptical loading a semi at .001" from the lands though. Even .003" IMHO. To me that increases the possibility of creating a malfunction at the worse possible time and in a semi it's doubtful you'll gain anything worth the trouble it takes to set close tolerances.
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  #15  
Old 04-23-2021, 06:57 PM
hebes405 hebes405 is offline
 
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Quote:
Originally Posted by la Fiere View Post
Me too. And although I know better than to argue with Ceresco, in a bolt gun it will make a difference.
It makes a difference in all guns.

I agree, no point arguing an answer that wasn't even close to answering the OPs question of where to start seating depth in a 308 bolt action rifle.
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  #16  
Old 04-24-2021, 01:13 AM
Bml Bml is offline
 
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You donít see people seating bullets close to the lands in semiís because usually the lands are far enough out the OAL of the round will not allow feeding from the magazine. The same problem occurs in many bolt actions too.
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  #17  
Old 04-24-2021, 06:18 AM
milprileb milprileb is offline
 
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As always, folks are thinking all reloading questions apply to the M1 Rifle on this forum and shooting accuracy is CMP Garand Match type accuracy...big targets at anemic 200 yds.

Seating depth : use factory COAL if its ammo for the M1 Rifle.

If its bolt action rifles that are not control fed from magazine you can indeed do load development that includes testing various seating depths and find which depth brings the best accuracy.
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  #18  
Old 04-24-2021, 10:09 AM
Gewehr43 Gewehr43 is offline
 
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Quote:
Originally Posted by milprileb View Post
As always, folks are thinking all reloading questions apply to the M1 Rifle on this forum and shooting accuracy is CMP Garand Match type accuracy...big targets at anemic 200 yds.

Seating depth : use factory COAL if its ammo for the M1 Rifle.

If its bolt action rifles that are not control fed from magazine you can indeed do load development that includes testing various seating depths and find which depth brings the best accuracy.
+1
We have everything from casual shooters to National record setters here.

OP:
As others have said, with a 308 bolt rifle you asked originally, you can see a positive result from testing the OAL.
I usually start about 0.1 and work back.
I like the buffer that that provides......

If you are using/testing Bergerís VLDís..... they have specific suggestions on their website.
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  #19  
Old 04-24-2021, 05:41 PM
britrifles britrifles is offline
 
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It’s surprising how accurate some rifles are with bullets that are seated far away from the lands. Accuracy is a relative term of course and what is considered an accurate rifle for one shooter looks like a shot gun pattern to another.

One example is the M1 shooting 125 gr bullets. They can be quite accurate (for an M1) and bullets are a long way from the lands.

I can shoot a 100-7x or 8x prone slow on the SR Target with my Long Branch No. 4 Mk 1/3, done this lots of times. That 174 gr SMK is outside of the case before it contacts the lands. I use this rifle to shoot VMR matches, and for that, it does its job well. If I don’t win the match, it is not because I didn’t find the right seating depth, it is because I got beat out by better shooters than me.

If I was building up a long range match bolt rifle then yes, I would experiment with seating depth.
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  #20  
Old 04-24-2021, 09:02 PM
GrampawEd GrampawEd is offline
 
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Well, after all the dos, don'ts, makes no nevermind and 30-06 talk, I found my sweet spot looking for accuracy from a 308 bolt action rifle. The rifle is a Win Model 70 Coyote with a Nikon M308 scope. I loaded 44.0 grains of Varget behind Sierra 150 grain Spitzer bullets. The best accuracy came from seating the bullets around .030 off the lands. My last three shots were in a group .75 inch center to center. This was the second acceptable group with these measurements. I have given the rifle to our son-in-law, along with 50 rounds of ammo loaded as close as possible to these measurements. He is a beginning shooter and I wanted to show him that whatever the target shows after his shooting, it ain't gonna be no ammo alibi. Thanks to all. we gotter done.
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