Bullet seating depth to lands

[ballistic64]

It seems when using a tool such as the stoney point, my cartridge length to the lands always comes up short as compared to using a neck turning expander in a case and just chambering to find the distance to the lands. After using the stoney point method, I can color the bullet with a marker, chamber it and find there is not a mark on it. I have generally found this difference can be anywhere from .007 to .020 depending on the bullet. The Bergers seem to have the biggest variance from the two methods. Is the stoney point case length gauge a waste of time? Which method of finding the lands do you use?

 

[Dusty Stevens]

The tool youre using is unnecessary imo. Seat a bullet long with some neck tension on it, steel wool it and close the bolt. No tools needed and no potential damage to your barrel with a chunk of steel that doesnt match your ogive anyway.

 

[ballistic64]

steel wool it?

 

[hdbiker1]

Steel wool will take the shine off the bullet and leave a kind of satin finish, which helps with seeing any marks left from the rifling.

 

[SHootSTraight22]

I don't use steel wool or anything like that because the land marks are easily visable on my Berger Hybrids after the chamber seats them into the case neck.... If you just have to mark something up I would recommend a "sharpy permenant marker" for viewing the land marks...

 

[Tim Singleton]

I have one quit using it as soon as I saw what you are seeing. Pushing the case in by hand won't replicate a case closed in a chamber by the bolt.

Dusty spoke of the method everyone I know uses

Just another gadget created with no real need for it

 

[SHootSTraight22]

I have one quit using it as soon as I saw what you are seeing. Pushing the case in by hand won't replicate a case closed in a chamber by the bolt.

Dusty spoke of the method everyone I know uses

Just another gadget created with no real need for it

I'm glad to see everyone else does this as well... I was wondering if I was just a cheap guy or if the method was the best to use?? I've posted on the method in the past by just calling it the "old school bullet in the case method.." It's what we all learned by reading reloading books of the past before someone figured out how to profit off of the procedure... On a side note I use it to keep up with my throat wear also..

 

[Dusty Stevens]

The old school method can keep up with throat wear just the same as it does to find it in the first place. Probably better as it uses your real components in real world conditions

 

[Danattherock]

Searching online yesterday and saw this...

http://bulletin.accurateshooter.com/2012/07/tool-tip-make-your-own-length-to-lands-gauge/

Simple and free

Dan

 

[josebd]

Frankford Arsenal Cartridge Overall Length Gage
this is kinda what i use,except mine is a steel rod,with 2 collars and set screws

 

[Brians356]

The Stoney Point (now Hornady) gauge, if used properly, works fine. But the modified case needs to be the same length to shoulder datum line as your sized and ready to load cases, and the body needs to be small enough in the head area to allow the case to push forward to shoulder contact with no resistance. Then the case and bullet both need to be held firmly in place against their respective stops while you tighten the lock screw. Are you using the S.P. modified case, or one of your own modified cases?

 

[ballistic64]

The Stoney Point (now Hornady) gauge, if used properly, works fine. But the modified case needs to be the same length to shoulder datum line as your sized and ready to load cases, and the body needs to be small enough in the head area to allow the case to push forward to shoulder contact with no resistance. Then the case and bullet both need to be held firmly in place against their respective stops while you tighten the lock screw. Are you using the S.P. modified case, or one of your own modified cases?

I was using the SP case. Neck turned it to .012 thickness and then ran it through my neck die bushing. I can feel the case and the bullet seat solidly when using it, but like I said after seating a bullet to the depth indicated with the SP gauge in a dummy round, I can come up with quite a difference (shorter) than if I just use my case neck expander (for neck turning) and chamber a bullet in the rifle, it doesn't require a lot of force with the second method and afterwards I can color the bullet with a marker, rechamber it and visibly see the land marks. It may in fact be something with the SP case causing this, as it is not a factory chamber.

 

[Brians356]

ballistic64,

Are you using VLD bullets? My hunch is that you are encountering a situation where "jammed" is not well-defined, in that the bullet will go a good distance into the bore beyond initial contact with the lands, applying relatively low force. And it is impractical to apply exactly the same force on the bullet with the S.P. gauge as you apply chambering a dummy round.

A problem arises when we want to identify some length which is "jammed" and expect that to be a hard number and 100% repeatable using two different tools. For my part, I don't care about the precise "jammed" length (if it even exists), all I care about is a baseline reference point, acquired (and repeatable) using the S.P. gauge. Then by testing seating depths as offsets from that baseline, I can say that loads which are a particular offset (could be shorter, or longer i.e. more "jammed") shoot best. I don't care if the baseline length is the mystical "jammed" length or not, it is what it is, and just a stake in the ground.

 

[ballistic64]

I have tried it with VLDs and Matchkings. I could very well be a tight throat I'm feeling with the VLDs when using the SP, as the barrel is new. The Matchkings seem to seat closer to the lands using the SP, in that there is only a .007" difference between the two methods when measuring with a SP comparator.

 

[BenPerfected]

Does the exact starting point on the seating depth really make any difference? You are going to be testing at numerous seating depths looking for the best SD on the target. When the best SD is found in combination with the optimum powder charge, etc., It is noted on the bottom of my barrels.

 

[JarheadAZ]

Unless I am shooting for an extreme accuracy application, I disregard the seating depth. My main criterion is to ensure that the every cartridge in the magazine feeds and ejects satisfactorily. Only when that criterion is met do I concern myself with seating depth, and that criterion for that is to ensure that none of the cartridges seat the bullet in contact with the lands. I color the ogive with a black permanent marker, and hand feed/close the bolt on the entire group of cartridges. If rifling engagement marks appear, I lower the seating insert 1/2 turn and try again. Once the cartridges exit with no rifling marks, I then lower the seating insert another 1/4 turn.

This is the point where I start doing load development for powder charge weights.

All my rifles have SAAMI chambers, to prevent my successors from encountering issues with factory ammo, and all my rifles have functional magazines, so that is the criterion that counts. The correct ammunition should feed from any appropriate magazines my rifles possess. I will sacrifice what small amount of accuracy I lose when I don't match OAL in reference to the rifling.

Greg

 

[Brians356]

Unless I am shooting for an extreme accuracy application, I disregard the seating depth. My main criterion is to ensure that the every cartridge in the magazine feeds and ejects satisfactorily. Only when that criterion is met do I concern myself with seating depth, and that criterion for that is to ensure that none of the cartridges seat the bullet in contact with the lands. I color the ogive with a black permanent marker, and hand feed/close the bolt on the entire group of cartridges. If rifling engagement marks appear, I lower the seating insert 1/2 turn and try again. Once the cartridges exit with no rifling marks, I then lower the seating insert another 1/4 turn.

This is the point where I start doing load development for powder charge weights.

Greg, a not unreasonable approach. But of course once you identify a "safe" seating depth WRT feeding, you are free to test even deeper seating starting there, incrementally increasing the bullet jump to find an accuracy sweet spot. There almost always will be one or more, even when the bullet is already jumping a very large gap. It's worth finding. But, as in most things, accuracy is in the eye of the beholder. And just tuning powder charge around a fixed jump probably yields a load with enough accuracy for the application.

 

[ballistic64]

Does the exact starting point on the seating depth really make any difference? You are going to be testing at numerous seating depths looking for the best SD on the target. When the best SD is found in combination with the optimum powder charge, etc., It is noted on the bottom of my barrels.

I just figured if the seating depth is started at the lands, there is only one direction to go.

 

[snakepit]

I have been using a method I learned from a posting on this forum a couple of years ago. I mix some JB Weld and coat the inside of the neck of a fired round. I seat the bullet long, insert it very carefully in the chamber and slowly close the bolt. I let it set in the chamber for 6 to 8 hours or longer. When you remove the shell you have a very exact seating depth to the lands. Now no matter what you do the measurement will remain the same because the bullet is set firmly and will not move if you drop it or close the jaws of the caliper too hard.

A couple of things to remember are once you close the bolt do not open it again until the JB Weld has set up and make sure the fired primer has been rermoved from the brass to get an accurate reading.

 

[JarheadAZ]

Brian, thank you.

My main accuracy goal is to defeat the target. What that means will be different for each target, but I think it will be easy enough to discern.

Greg