bullet seating depth question for .308

[ReaperDriver]

I know every gun is different.... but in general - is the feeling that longer is better?(insert snickering here) I've been browsing the load depot and peoples seating depth seem to vary wildly from really long to the book standard of COAL 2.800. But at a glance, it seems like most people are seating bullets somewhat longer COAL than the reloading manuals specify. How do you guys arrive at that number? A lot of trial and error or do you just pick a number and go with it?

Related Q: do tight custom match chambers tend to prefer a different seating depth over factory tubes?

 

[desertHK]

Re: bullet seating depth question for .308

First you need to establish the chamber length for your stick. This can be done with a Hornady OAL gauge. You need to measure that with the particular bullet that you are going to shoot. This gives you the length that your COAL is. Most people would recommend backing off from the lands about 0.005-0.010" and this should be your max OAL. Some bullets like the Berger VLD bullets prefer to be jammed into the lands, whereas the AMAX and Scenars prefer not to.

 

[308sako]

Re: bullet seating depth question for .308

...

 

[18Echo]

Re: bullet seating depth question for .308

I used the Hornady oal gauge and then backed off the lands .020 for my .308 Gap. Judging from my last trip to the range for load development thats a sweet spot for my gun, varget, and 175 SMK.

On the oal gauge I found that i wasn't getting consistent measurement with their instructions, so I used Zedikers instructions and it worked beautifully.

 

[ReaperDriver]

Re: bullet seating depth question for .308

I may have to pick up one of these OAL gauges and see. But I have a factory Rem 700 SPS-T and have always heard that the chamber is WAAY long, so I wonder if there is any way to get the bullet that far out to get w/in .020-.010 to the lands.

 

[DocB]

Re: bullet seating depth question for .308

RD,

I seat 210 JLKs to 3.240" in order to get a jam fit in my Remington factory rifle. The JLK is the only bullet I could find which would stabilize in a 1/10 twist barrel and get close to the lands. They shoot well, fortunately.

Getting the bullet comparator is a good recommendation, and it's cheap.

YMMV,
DocB

 

[GOING FOR 2000]

Re: bullet seating depth question for .308

Don't assume that .010-.020 is the sweet spot. mine is .158 off in a 700P, 175 Gn. SMK. Start at 2.800 oal and work out from there.

 

[teknikallysekure]

Re: bullet seating depth question for .308

Where can we find Zedikers instrucstions for the use of the Hornady OAL tool?

 

[18Echo]

Re: bullet seating depth question for .308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: COURAGEWOLF</div><div class="ubbcode-body">Where can we find Zedikers instrucstions for the use of the Hornady OAL tool? </div></div>

I don't remember if it was in his book or somewhere else. Basically hornady says to put your bullet in the gauge, insert gauge into chamber, push bullet with the gray stick thingy until you just feel it kiss the lands. I got ten different measurements on 10 different trys, probably operator headspace and timing...

anyways zediker says to load the bullet long in the gauge and tighten down the gray thingy push rod so that it gives good, but not total resistence. push the gauge into the chamber fully. tighten the lock screw so the push rod is fully locked down. remove gauge, run a cleaning rod through barrel to knock out bullet, put bullet back in gauge and measure.... in a nutshell....

 

[JerkeeJoe]

Re: bullet seating depth question for .308

Jeff, I've got a Hornady OAL gauge that you're welcome to use. It's really easy to use and allows you to figure your max oal in about 3 minutes. Shoot me a message or give me a call if you want to check it out.

Joe

 

[LA_Lawman]

Re: bullet seating depth question for .308

if i am training at work, I use ammo that is seated to mag length. If I want to see how tight i can get a group, i fiddle with the jump and jam. my rem700 likes a little jump, but my savage likes a jam....

 

[teknikallysekure]

Re: bullet seating depth question for .308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 18Echo</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: COURAGEWOLF</div><div class="ubbcode-body">Where can we find Zedikers instrucstions for the use of the Hornady OAL tool? </div></div>

I don't remember if it was in his book or somewhere else. Basically hornady says to put your bullet in the gauge, insert gauge into chamber, push bullet with the gray stick thingy until you just feel it kiss the lands. I got ten different measurements on 10 different trys, probably operator headspace and timing...

anyways zediker says to load the bullet long in the gauge and tighten down the gray thingy push rod so that it gives good, but not total resistence. push the gauge into the chamber fully. tighten the lock screw so the push rod is fully locked down. remove gauge, run a cleaning rod through barrel to knock out bullet, put bullet back in gauge and measure.... in a nutshell.... </div></div>

Thank you.

 

[Vindex]

Re: bullet seating depth question for .308

Instructions:

http://www.6mmbr.com/catalog/item/1433308/977259.htm

 

[ReaperDriver]

Re: bullet seating depth question for .308

Joe, I'll take you up on your offer one of these days just for shiggles. But I've kinda made he decision that mag length is my limit as I have no desire to limit muself to single load. It might shoot tighter groups but it has no usefulness for me if I can't shoot from the mag.

Fortunately, now that I have BM with AI mags, I can go all the way out to 2.88 now. I'll just keep playing with seating depth between 2.80 and 2.88 and se what works

 

[Jedi]

Re: bullet seating depth question for .308

Hmmm
K as always there is a right and wrong way

Firstly boat tail junction of bullet should be @ neck junction of case for given bullet

LOad a dummy round to that spec smithy will cut chamber based on that and any crush or freebore relation to lands desired.

So has you already rifle
the above still applies unless you have a huge chamber, you maybe lucky and after creating dummy round find your chamber/throat is to short. Have a smith rethroat it done deal.

Now if your chamber is still way long
load to MAX mag length that will reliably feed, tweak from there until it shoots per your needs

 

[30378]

Re: bullet seating depth question for .308

It also depends on the specific projectile being used or better know as the difference in ogive. I would seat say a 175gr Berger out further than a 150 Nosler Ballistic Tip just based on the OAL of the projectile.

 

[mpheithoff]

Re: bullet seating depth question for .308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: L.A. Lawman</div><div class="ubbcode-body"> my rem700 likes a little jump, but my savage likes a jam.... </div></div>
<span style="font-weight: bold">
Does it seem that this is just a rifle to rifle difference, or do heavy barrels like one and hunting rifles another. Or high muzzle velocities one and low another. High BC's vs Low... you get the idea.....?</span>

 

[Quackaddict]

Re: bullet seating depth question for .308

From what I have read, it kind of depends more on the bullet than anything, bergers seem to prefer being jammed, I have read more than once SMKs like to be jumped.

I start load development .015 off the lands if the bullet allows me to do that

 

[Quackaddict]

Re: bullet seating depth question for .308

From what I have read, it kind of depends more on the bullet than anything, bergers seem to prefer being jammed, I have read more than once SMKs like to be jumped.

I start load development .015 off the lands if the bullet allows me to do that

 

[JuniperEyes]

Re: bullet seating depth question for .308

Playing with some new Sierra 2156 155SMK loads recently and found best accuracy seating at 2.815, a full .065 off the lands.

Other rifles and other loads liked different seating depths, some jammed, some close, and some far away.

Like others have said, you just never know.

If you are intent on mag length, run the OCW drill to find the best charge of powder you intend to use. Then try different seating depths to try and fine tune the load.

Im not saying this is the best route, but it gets me there.

Good luck and enjoy shooting the rifle while developing the load for it.

 

[redgtsviper]

Re: bullet seating depth question for .308

A lot of trial and error, find what shoots best in your gun

 

[vman]

Re: bullet seating depth question for .308

Quick question...

Obviously changing the seating depth will also alter the pressure generated for any given load.

Whats the general order in how you work out the optimal OAL and then the powder charge?

Would you just work out your powder first and then play with seating depths?