Overall Length

[SWAMPFOX]

I recently acquired the Hornady Overall Length gauge and the .30-06 case to use with it. My rifle is a Savage 110.
My question is about how far off the lands should I start to determine the best OAL for this rifle? Naturally what I'm looking for is the optimal free travel/clearance/jump to the lands of the rifle. But I need a starting point.
Thanks.

 

[transfixer]

Do you reload ? if you do I would size a fired case, don't prime it and leave it empty, then seat a bullet into the case just barely, chamber it and it should push the bullet in to contact depth, you should be able to see rifling marks on the bullet, then measure the oal, and back off from that measurement however much you think you want . There may be a better way, but that's the only way I know, I used that method on a rifle a long time ago, haven't worried about it lately.

 

[BriarPatch99]

I like to seat a bullet long .... then Mark the bullet all over with a black magic marker ... you will be able to see the "copper" shine through the black at the point of contact .... I then seat the bullet until the contact marks become very faint .... at this point your bullet is touching the rifling .... Keep this measurement( from the base of the brass to point of contact) noted ... You will now be able to reference this number as a means of how much you are off the rifling for THIS particular bullet ...

You will have to do this for every different bullet and even if the maker changes the profile for this bullet ....

 

[Buckstop]

I assume your speaking of hornady’s gauge and test case to measure the distance from the case base to where to bullet’s ogive contacts the lands.

Once I determine to case base to lands distance, I usually start .010 off the lands working up in charge weight till I find an accuracy node. Then I fine tune the seating depth working on out in .010 increments from .010 to .060.

Some bullets like bergers, sierra’s and accubonds seem to like to be seated close to the lands. I’ve had better results with hornady’s eld’s with .030 or more jump.

 

[WGSNewnan]

i usually start at .010.

having owned numerous 110's over the years ( currently hunt with 110 TH XP .270), it really didnt matter whether it was 10 or 60. they would all shoot sub moa with my handloads.
for that matter - my current load loaded to oal of 3.210 using 140gr sst over 57.5 4831 shoots 1/2 moa. 5 shots into 1 ragged hole. didnt even bother to check the jump.

 

[Darkhorse]

I do mine the same way as Transfixer and Briarpatch99 and hunt for a node like Buckstop describes.
I keep detailed notes and build a seating depth list for every different bullet I try.
However I don't measure OAL when loading rifles, instead I use Hornady bullet comparator gauges attached to my Starret dial calipers and do all my measuring to the ogive of the bullet. This is the part that actually engages the rifling. OAL only becomes important if a clip is too short.
I shoot a string of 3 targets with seating depths .010 apart. I will also shoot strings of 3 targets with varied powder charges. I can go back and look at several targets at once and really see how I'm affecting my groups.
This target shows how the groups open and actually move POI when changing seating depths. Using these measurements is part of how I build a load for a bullet and rifle.
This is a really simplified explanation of my process, right or wrong.

 

[killerv]

I like to start with .010 off if magazine allows and work from there. If the guns doesn't cycle worth a darn...then whats the point....

My model 7 708 had to be loaded to .040 off to cycle through the magazine reliably. It still shoots under an inch @100. Also not a bad idea to simply start with book length for your particular bullet...it may do quite well...then you can find the lands and do some tinkering.

Make sure the chamber is nice and clean before you start measuring.

 

[SWAMPFOX]

Darkhorse, so the very first part of a bullet to contact the lands of a rifle is the ogive?

 

[nmurph]

Yes.

https://www.sinclairintl.com/guntech/determining-bullet-seating-depth-/detail.htm?lid=16131

 

[treemanjohn]

Make sure it's not too long to fit in the mag and the action functions properly. It';s a tough question to answer without a little investigation

 

[Darkhorse]

Swampfox, yes it is. You can take a bullet seated a little too long in a partially sized case mouth (just enough to hold a bullet where it can slide a little), paint the exposed bullet with black magic marker now chamber the round in your rifle and carefully extract it. Now look at the bullet and you should see a series of marks some distance back from the tip. This is the ogive and it's what's actually touching the rifleing.
Now some rifles with clips won't allow enough length to reach the ogive with a loaded round. For instance my Browning .300 Win. Mag. has a short clip and closest I can get is .100 (almost 1/8") from the ogive.
A few years ago bullets had lead tips and measuring OAL on all loaded rounds would reveal the cartridge length varied, sometimes a good amount. This was caused mostly by the lead tips. Today's nylon tipped bullets are more uniform than the older ones though. When I finally realized what was happening I went to measuring only from the ogive.

 

[pse hunter]

my savage 116 likes the 178 gr hornady eld-x at .010 off the lands i would start there and work back from there, I used the Hornady Overall Length gauge to find the lands as well

 

[BriarPatch99]

Darkhorse, so the very first part of a bullet to contact the lands of a rifle is the ogive?

In a perfect world ... a .30/06 would have a bore diameter of .300" and a Groove diameter of . 308" . ...

So yes the Ogive of a bullet is usually the first part to touch . in a perfect world ... contact is made at the part of the Ogive that is .300" . ... then the rifling begins to engrave the bullet ...with the bullet sealing the groove diameter at .308" . ..well enough to contain the 60,200 psi of pressure...

Hopefully this photo will help ... the right red line is about where the Ogive enters the rifling .... the section of the bullet between the two lines is the bearing surface of the bullet ...

The part of the bullet to the right of the right hand line never touches nothing but air until it hits the target( it may or may not the front of the magazine before being chambered)...

The section to the left of the left line would only contact the hot gas of the burning powder then deals with air flow over the bullet until it hits the target....l