Bullet seating depth to lands

[Brians356]

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.

That's an attractive idea. I would be inclined to size the neck so the bullet could be seated by hand (with some force, so it couldn't just fall out) which might require a mandrel. You size to, what, .001" smaller than the bullet?

Not much risk of glue squeeze-out if done properly, but just to help me sleep I would swab the chamber neck with a film of Rem Oil anyway.

 

[Brians356]

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

Probably most anywhere "in the hair" will do. Wish I was more disciplined about that. I shot at a coyote last weekend with a Sako Vixen in 222 Rem that will hit a nickel at 200 yards without much fuss, but since I always overestimate the range to coyotes (they look so tiny!) I held at the top of his back and shot over him - again. I was by myself, no spotter, and no rangefinder with me. The rifle is zeroed at 200 yards, so point-blank range is about 240 or so for a coyote. In retrospect the dog was only about 175. When in doubt, just aim at the damned target and let fly, dummy!

 

[SHootSTraight22]

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.

That's an attractive idea. I would be inclined to size the neck so the bullet could be seated by hand (with some force, so it couldn't just fall out) which might require a mandrel. You size to, what, .001" smaller than the bullet?

Not much risk of glue squeeze-out if done properly, but just to help me sleep I would swab the chamber neck with a film of Rem Oil anyway.

I agree.. I would be worried about getting some in the chamber, plus when I do the "bullet in the empty case thing" I like to go through the procedure multible times.. I'll chamber it then measure, then redo the test again..., I do this enough times where I know my final measurement is dead on... Also I've seen dirty barrels give false measurements as well, so doing this on a clean throat and multible times helps my confidence at least...
Brain356,, I couldn't help but notice you mention coyote's.. I was just wondering if you hunt coyote's in the east (meaning not dry environment skinny yotes out west) and if so are yall noticing big huskey looking yotes and even some that resemble a dog but dark colored... I've been told that these dark yotes running with the others are "swamp wolfs.." I've also been told that we may have wolf/yote hybrids down here in Alabama.. Our coyotes are huge with siberian husky type coats.. It's normal to see a 70-100lb coyote where I hunt! Is that normal or do you coyote hunting guys think we have some mixing going on??? PS We have real mountain lions breeding black one also but the government want admit it and discovery channel will make some show about it like it aint true but it is!!

 

[Brians356]

SHootSTraight22,

I hunt in the high and dry Great Basin where coyotes tend to be small to medium-sized. My hunting buddy here who went to college (wildlife management) in NC, had parents in AL and family in FL, knew all about the expansion of coyotes into the SE, wolves, interbreeds, cats etc in your area, but he just passed away so I can't consult him on your topics.

The glue-in method is rather brute force, and in a sense tosses out the window the idea of repeatable measurements - he's jamming a bullet and saying "For better or worse, this is my baseline dummy round." In a sense it doesn't matter if the next several ones created would all measure exactly the same, but there's a chance they would be very close, depending on the bullet profile and how tight the neck is. I'd be curious, actually.

 

[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. I don't use the oil in the neck,

That's an attractive idea. I would be inclined to size the neck so the bullet could be seated by hand (with some force, so it couldn't just fall out) which might require a mandrel. You size to, what, .001" smaller than the bullet?

Not much risk of glue squeeze-out if done properly, but just to help me sleep I would swab the chamber neck with a film of Rem Oil anyway.

I use a fired case which I run through a body die or a FL bushing die without the bushing installed and I run a brush through the neck or use a shell that has been cleaned. I do not resize the neck at all. Make sure the fired primer has been removed. I use a toothpick to install the JB Weld in the neck and usually put it in pretty thick, .Then I wipe the neck off just in case I got some on the neck. I just seat the bullet in the neck to where it is not seated too far in, then I start the bullet in the chamber using my finger and finally close and lock the bolt very slowly. With a single shot rifle this is pretty easy to do. I have done this procedure numerous times over the past few years with no problems on several different rifles. I do it every 150 to 200 hundred rounds checking for throat wear, when I start a new batch number of bullets and when I get a new barrel. I never have had a problem with this method. In the beginning I would borescope the chamber after the procedure to ensure there was no glue in the chamber but that was never a problem. If you want to neck it down some that would probably be ok but leave it loose enough that it does not try to push into the lands. Another thing I do is lay the rifle flat afterwards as I want to make sure the JB weld does not flow down to the primer hole. I am sure it would not happen but just in case. I don't oil the inside of the necks as I wouldn't want a layer of oil between the JB Weld and the case.

 

[Brians356]

I would be inclined to stand the rifle vertically, muzzle down, so gravity would hold the bullet against the lands, and centered in the neck (assuming there's any wiggle room.) JB Weld is pretty thick when mixed, and slow-setting, so especially if you let it sit for ten minutes or so before applying it, there's no way it is going to flow anywhere on its own. But if the chamber and bore were oiled slightly, glue would not adhere should any happen to come out.

 

[savagedasher]

I'm with Hillary on this 😆 Really what difference does it make 🙈 It just a reference point to start with in the reloading process Larry

 

[Brians356]

I'm with Hillary on this 😆 Really what difference does it make 🙈 It just a reference point to start with in the reloading process Larry

Fair enough. Then why wouldn't you just seat a bullet to some arbitrary depth, short enough to clear the magazine (and therefore short of the lands) and call that your reference? You wouldn't know what bullet jump it represents, or care, apparently, but after all, it's just a reference to start from.

 

[snakepit]

I would be inclined to stand the rifle vertically, muzzle down, so gravity would hold the bullet against the lands, and centered in the neck (assuming there's any wiggle room.) JB Weld is pretty thick when mixed, and slow-setting, so especially if you let it sit for ten minutes or so before applying it, there's no way it is going to flow anywhere on its own. But if the chamber and bore were oiled slightly, glue would not adhere should any happen to come out.

I did not mention it but I do let the JB weld start to set up for about 10 minutes or so then check it with a toothpick before I use it. I just figured that when you close and lock the bolt the bullet is locked in against the lands and not going anywhere if laid on its side. What I have done many many times the last few years has worked great for me but like many reloading ideas there are many ways to do the task at hand.

 

[savagedasher]

I'm with Hillary on this 😆 Really what difference does it make 🙈 It just a reference point to start with in the reloading process Larry

Fair enough. Then why wouldn't you just seat a bullet to some arbitrary depth, short enough to clear the magazine (and therefore short of the lands) and call that your reference? You wouldn't know what bullet jump it represents, or care, apparently, but after all, it's just a reference to start from.

I will give you simple answer why you're way will not work.
We will take a 308 Winchester for a reference
Maximum C. O. A.L. Is 2.800. That number works with most bullets 180 GR or heavier.
The C. O. A.l. On a 110 GR is 2.500 for a reason the bullet is too short to be seated.
One of the the first things you do in reloading is start low and work up.
That applies to seating bullets touching the lands can change maximum pressure as much as 5000 PSI.
I never have used my chamber all gauge for making adjustments in my seating depth.
Larry

 

[Sheldon N]

Yes, chamber pressure would be the reason it's helpful to know where the lands are. If you work up a load to near max, then seat out longer and reach the lands the increased pressure could make it into a dangerous/overpressure load.

My understanding is also that it's generally not the best to seat exactly at the point the bullet starts touching the lands, since small variations in loading depth can result in the difference between jump/jam. I think the recommended course is to either back off .005 and jump, or go in a bit and make sure that you're fully jammed.

I personally use the Hornady gauge, but I use a cleaning rod down the barrel so I can push the bullet back/forth and feel exactly where it starts to kiss the lands.

 

[quartermaster]

Keep in mind that using the Stoney Point or now Hornady method, you are using a modified case that will chamber in any rifle, therefore being short as far as headspace goes compared to your rifle. If you were to take a fired case from your rifle, decap the primer, drill and tap the primer pocket and then use your Hornady gage, you would be very close depending on your case being fully fireformed.

I forgot the drill size (maybe 19/64") and the tap size. I bought them, but have never used them yet, as I agree with the above posts that it much easier to take a case, in my case, neck down to .001 neck tension, seat a bullet long and chamber it. This is the most accurate way IMO to get the measurement. Many times a fired case will still give you enough neck tension to allow you to insert a bullet nd chamber and extract without the bullet being stuck in the throat.

QM

 

[Brians356]

Keep in mind that using the Stoney Point or now Hornady method, you are using a modified case that will chamber in any rifle, therefore being short as far as headspace goes compared to your rifle. If you were to take a fired case from your rifle, decap the primer, drill and tap the primer pocket and then use your Hornady gage, you would be very close depending on your case being fully fireformed.

You should also size your self-modified case's body / shoulder to match what you intend to shoot in the rifle. Otherwise its shoulder will be farther from the case's base than your loaded ammo's shoulder, and that will skew your assumed length-to-lands figure.

Again, this only matters if you want to know the seating depth to the lands for a particular bullet ogive, and reference that to be able to say what the bullet jump really is, and to then be able to seat "touching" or even "jammed".

PS

Also, you need to make sure the fired case's body is not too tight a fit in the chamber, as it must chamber easily so that the shoulder makes firm contact in the chamber with no extra force applied. If you ever find the case doesn't come back out of the chamber easily, that's a bad sign, it means it's wedged in there, and you can't be sure the shoulder is making firm contact. Repeatable readings will likely be elusive..

I became curious about the length to shoulder datum of the Stoney Point 223 case compared to my own modified case. Using the Hornady L&L "headspace" bushing, I was surprised to discover the S.P. case measured exactly the same length as my own case. I.e. making my own case was a complete waste of time.

 

[rmist]

The drill size you need to make your own case is a letter L size bit. I make them all the time for my rifles and have very excellent results with them. I have made up dummy rounds as well seated long and I can repeat the same measurement. Once I find the jam I'll seat a bullet use 0000 steel wool to clean the bullet, chamber and see the marks wide and thin from the rifling.

 

[Brians356]

The drill size is not a problem, you can get away with slightly larger 19/64, the threads don't need to be very deep. The tap is a real oddball, nothing you can pick up at Ace or Lowe's. I found one at a local industrial supply catering to machine shops. I forget the designation.