.308 berger OAL

[jersurf101]

I am making some .308 win rounds using new Win brass and 168 grn Berger VLD's. After researching the subject I have found that Berger says you will find your sweet spot between .012 and .004 off of the lands.

This brings me to my question. I have measured the distance and it puts my OAL at 2.92 touching the lands. So it would seem that I should try 2.78 through 2.88 in OAL to start looking around. The problem is this exceeds the 2.80 OAL per Lyman 49. Is it safe to seat these o out further than the 2.8 inches if I keep them out of the lands?

I will be using 41 grains of IMR 4064 and the gun is a new savage Model 11. The magazine will accept rounds up to 3 inches long.

 

[Revoltella]

The Lyman number is to fit any .308. You've measured your chamber and loading for your particular gun. You're fine.

 

[oldscot3]

If you're at 2.92, .004 would be 2.916 and .012 would be 2.908. Both of these will be fine but may not fit in your magazine. If you're target shooting, single feed them, otherwise load them as long as your magazine will allow you to and see if they offer you the accuracy you want.

 

[jwrowland77]

I run into the same problem with my Savage Axis. I run my match ammo at 2.900 using SMK but I could go out to 3.000 and still be off the lands plenty far enough. As said 2.800 is just what they used. My OAL of 2.900 fits my mag with plenty of room, but shooting match, you single load any way.

You're good to go at the longer OAL.

 

[jersurf101]

Thank you for the replies.

And the math lesson.

I will load them at 2.911 to start.

 

[steve4102]

The OAL listed in the manual has little or nothing to do with you and your rifle. The handloader is free to adjust his/her OAL to whatever they wish.

From Accurate/Ramshot.

SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL”
It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must be seen as a
guideline only.
The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.
This parameter is determined by various dimensions such as 1) magazine length (space), 2) freebore-lead dimensions of the barrel, 3)
ogive or profile of the projectile and 4) position of cannelure or crimp groove.

 

[jersurf101]

Cool. Good to know. I just want to keep things safe. I just wanted to see if this passed the good old smell test.

 

[Bart B.]

Measuring the over all length (case head to tip of bullet) on bottleneck cases headspacing on their shoulders will not reflect detail to .001" accuracy in your chamber. That number's controlled more by the distance from the case shoulder to the bullet's ogive point where it contacts the leade in the rifling (about the .304" diameter point on 3082" Sierra match bullets ogives). Why? Those cases' shoulder stop against the chamber shoulder from firing pin impact when they're fired; the case head is forward clear of the bolt face by a few thousandths.

As most resized bottleneck rounds have a few to several thousandths spread in this dimension, that'll be part of what governs the measurement. The precision of the bullet's ogive shape will control the rest of it. I've measured a lot of 30 caliber hollow point match bullets' distance from their .3000" diameter point on the ogive to the tip of the hollow point. A .004" spread is common, but they shot well under 1/4 MOA in Sierra's 200 yard test range.

 

[jersurf101]

Good information Bart b. I have read some things on bumping the shoulders back and did not fully understand the correlation. This is a good explanation and explains why lee Collet dies are good to have.

 

[Unclenick]

Jersurf,

The problem is your original numbers from Berger are wrong. You've got extra zeros after the decimal place. Berger's seating depth finding procedure, from the horse's mouth, is here.

 

[Bart B.]

Jersurf, bumping fired case shoulders back can be very well controlled and have a small spread across a batch of cases of less than .002". Plenty good enough for best accuracy. A uniform amount of case lube on cleaned cases helps a lot. So does the use of Redding's competition shell holders in different heights; use the one that when it stops against a full length sizing die, the fired case shoulder's set back very repeatably where it's needed.

Lots of folks use Lee Collet dies to size necks but they have never found favor with folks attaining best accuracy with more conventional sizing dies. Collet dies don't hold the fired case body well aligned with the die's neck area when the fired case neck is sized down. Necks are better centered on case shoulders when sized in full length dies. This is why most of the benchresters switched from neck only to full length sizing dies a few years ago. Sized necks float free in the chamber neck when the round's fired on cases headspacing on their shoulders. Any off center of the neck axis on the case shoulder will be duplicated in the chamber neck.

 

[jersurf101]

Unclenick, after looking on the Berger wbsite i decided to load 4 different oal's

2.912
2.882
2.842
2.802

I will try these on Sunday. Thank you guys for the help

 

[jersurf101]

Got a range report for the Bergers in the new Savage model 11. I found good accuracy at .080 and at .010 out out of the lands. .010 out of the lands was the better grouping by far.. Thank you for your help guys my grouping was all three shots touching.

The gun is shooting 7.62 x 51 150 gr surplus reasonably well. I tried a box of 180 grain federal fusion and it was terrible like 5 inches at 100 yards.