Inconsistent seating depths

[Lead Slanger]

I've had all my reloading equipment for seven or eight years now, but just now got around to getting a bench made, getting everything mounted and started putting it to use. So, as you can see, I'm a newbie. I went with a Lee 4 hole turret. I have five or six calibers I want to load for, but right now, I'm only working on loads for my 6.5 Creedmoor. A chronograph is next on my "have to get" list so I can get serious about finding the right load for my rifle. Until then, I'm just loading to shoot for groups.

As you can see from the title, I'm getting inconsistent seating depths. Currently in the the press is a Lee Collet neck sizing die and a Lee Dead length seater die. I'm working with virgin Hornady brass, so no body sizing die needed at the moment. I do run them through the neck sizer, but I'll be honest, I haven't measured the neck tension. I don't think neck tension is the problem through. The components are virgin Hornady brass and Hornady match 140gr. BTHP's. I'm getting .005 variation between rounds. Being a machinist, I really want to spring for a competition micrometer die. It just makes sense. Until then, is there anything that I need to look for? I read where sorting bullets would help??? I'm measuring to the ogive, so I don't know what the base to ogive measurement has to do with anything.... Unless the bullets that much different where the seating stem is hitting them? Or would you think it would be the die? I also have a RCBS seating die that I haven't tried. If I were home right now, I would, but I'm not so I figured we could bench race about it. What do y'all think?

 

[RGRobinett]

First, check the nose: seater stem contact per sketch, and correct if you have either of the bottom pair.
Ideally, a proper mating requires lapping to a specific bullet (nose profile). Contact at any point on the me'plat is undesirable, as there can be a fair amount of variation there. For bullets made in a single point die, relative to land contact/seating depth, base to ogive is a meaningless number. A wide BtO variation is
indicative of either multiple dies, or, a varying (poor) set-up. Land:give relationship (seating depth) is determined by the distance from the seater stem contact point to the shank/ogive tangent point. RG

 

[William Vogel]

The seating die probably has nothing to do with the inconsistency as long as it’s locked. You need a mandrel die to enlarge the neck. I’m not familiar with the Lee neck die. I use F/L bushing dies and a mandrel. I also anneal after each firing. My seated bullet lengths are within .002 at the most but usually within .001- .000. I don’t sort bullets. I use a lot of Hornady bullets for everything except my 6 Dasher. The Dasher is the most consistent round I load and I use Berger 105 hybrid target. It’s a benchrest gun. My factory guns are Remington 700’s and they have specs that are not perfect and I shoot the Hornady bullets from them. I’m proud of the factory rifles, they (I) shoot less than 1/2 MOA on most days with them but they don’t have the tolerance of my benchrest rifles. I think without knowing what your powder charges are, that brass prep is probably the seating inconsistency.

 

[Lead Slanger]

First, check the nose: seater stem contact per sketch, and correct if you have either of the bottom pair.
Ideally, a proper mating requires lapping to a specific bullet (nose profile). Contact at any point on the me'plat is undesirable, as there can be a fair amount of variation there. For bullets made in a single point die, relative to land contact/seating depth, base to ogive is a meaningless number. A wide BtO variation is
indicative of either multiple dies, or, a varying (poor) set-up. Landgive relationship (seating depth) is determined by the distance from the seater stem contact point to the shankgive tangent point. RG
View attachment 1476432View attachment 1476432

Looks to improper #2. It's leaving a ring on the bullet a little ways down from the tip. (Explained in picture.)

 

[Lead Slanger]

The seating die probably has nothing to do with the inconsistency as long as it’s locked. You need a mandrel die to enlarge the neck. I’m not familiar with the Lee neck die. I use F/L bushing dies and a mandrel. I also anneal after each firing. My seated bullet lengths are within .002 at the most but usually within .001- .000. I don’t sort bullets. I use a lot of Hornady bullets for everything except my 6 Dasher. The Dasher is the most consistent round I load and I use Berger 105 hybrid target. It’s a benchrest gun. My factory guns are Remington 700’s and they have specs that are not perfect and I shoot the Hornady bullets from them. I’m proud of the factory rifles, they (I) shoot less than 1/2 MOA on most days with them but they don’t have the tolerance of my benchrest rifles. I think without knowing what your powder charges are, that brass prep is probably the seating inconsistency.

Here's a description about the Collet neck sizing die.....

"Lee Collet Neck Sizer Die sizes only the neck to preserve the perfect fit of fire forming. A collet squeezes the case neck against a precision mandrel for a perfect bullet fit with minimum run-out. No case lube is needed. Cases last about 10 times longer. Only reload cases that have been fired in you firearm. Not recommended for autoloaders, slide or lever action guns."

The charges I loaded last night were 39.5 grains of H4350 and 39.5 grains of Accurate 4350.

 

[William Vogel]

Here's a description about the Collet neck sizing die.....

"Lee Collet Neck Sizer Die sizes only the neck to preserve the perfect fit of fire forming. A collet squeezes the case neck against a precision mandrel for a perfect bullet fit with minimum run-out. No case lube is needed. Cases last about 10 times longer. Only reload cases that have been fired in you firearm. Not recommended for autoloaders, slide or lever action guns."

The charges I loaded last night were 39.5 grains of H4350 and 39.5 grains of Accurate 4350.

The collet die may be good but I like what I use because it’s sizing in two steps. If your brass has neck thickness variation between cases then it’s squeezing differently. And of course my method would also work the brass a little more because I push the neck below the needed diameter and then expand it open with the mandrel. I don’t know what to tell you because we’re using different dies. I don’t think it’s the seating die though. I do know that bullet ogive inconsistencies will cause seating depth inconsistencies. My comparator insert doesn’t measure from the same place on the ogive that the seating stem engages but I have pretty good consistency. The only sorting that I do is to split the brass into two groups based on the feel of the expanding mandrel but this only seems to occur on my Starline .308 brass for my M1A. My Lapua and Alpha brass is more uniform.

 

[nksmfamjp]

If you are getting a ring, you either need a custom seater plug or you need to make your own with a couple bullets, flitz, a drill and a vise!

 

[Orr89rocz]

If you are getting a ring, you either need a custom seater plug or you need to make your own with a couple bullets, flitz, a drill and a vise!

Or neck tension too tight requiring more seating force and causing the ring. For me i had tight necks in my wsm and my 257 bob. The berger vld would get a ring seating the wsm until i went to a bushing die and opened up neck. The 257 i use sierra gamechangers and they are soft enough that the jacket collapses at the ring/contact point. Im trying a new die set for that and have lubed bullets before seating with the old die set and eliminated the ring

 

[nksmfamjp]

Or neck tension too tight requiring more seating force and causing the ring. For me i had tight necks in my wsm and my 257 bob. The berger vld would get a ring seating the wsm until i went to a bushing die and opened up neck. The 257 i use sierra gamechangers and they are soft enough that the jacket collapses at the ring/contact point. Im trying a new die set for that and have lubed bullets before seating with the old die set and eliminated the ring

Excellent point!

 

[NZ_Fclass]

All of the above! Plus - just ensure that you are not seating bullets too far into the case as to contact the powder. If your neck tension s too light, the powder will push back.

Keep going. Reloading looks easy but now you are finding the little traps that are set! When I started, albeit pistol rather than rifle, I made all the usual mistakes - double loading (32 S+W so not so dangerous) No powder. No primer. Lousy loads. I do wonder now how I got through a match...but I did, and did OK too. My first press was alsoa Lee turret - and it got me into "A"grade before I changed to a Dillon, mainly for ease and speed.

It's very satisfying when your handloaded ammo starts to produce results.

 

[RGRobinett]

Looks to improper #2. It's leaving a ring on the bullet a little ways down from the tip. (Explained in picture.)

The ring calls for lapping to make a larger/longer mating surface. RG

 

[SSchnd]

Pull the stem out of the die, Inspect the seating end of the stem for micro cracks. Another shooter was having issue, sure enough his stem at the seater end has a fracture and was allowing slight variations. Easy to check if not already noted or mentioned. Would get a snapping sound as the bullet would stick into the stem then release and the inner sleeve would snap back. Very minor but just easy to check and make sure.

 

[txtaxman]

.... The components are virgin Hornady brass...... It's leaving a ring on the bullet a little ways down from the tip....

If you have not already done so, try chamfering and deburring the case mouths. Additionally, try lubing inside the case necks before seating the bullets, as new cases are very grabby.

 

[Coyotefurharvester]

Tight seating/ring marks can also be a sign the seating die body height is allowing a slight, inconsistent crimp. An inconsistent crimp will result in a cbto length variation. You should be setting the die body high enough to avoid crimping, as it is probably not needed and if you decide to crimp brass must be the SAME LENGTH. Seating die body is usually set with a case in the shell holder and ram up all the way up, different than a sizing die body.

 

[DW T or C]

The ring calls for lapping to make a larger/longer mating surface. RG

Do you have a process for doing this? How do you go about lapping the ID of the seater steam to make better contact with the bullet?

 

[KMW 1954]

.005", I wouldn't bother though some do. I load 223 and use a Hornady BTO measure and load to 1.910 as a target point. 1.905 to 1.915 will all shoot to the same POA.

The profile of the bullet is not exactly perfect either, even when measured from the ojive. Also using virgin brass can have an effect. Fired brass has carbon residue which acts as a lubricant which aides seating. Ask those tumbling brass with SS pins they experience the same issue.

 

[Ned Ludd]

I would suggest a couple things to start. First, determine your neck tension (interference fit). It's easy to do, simply measure neck diameter before and after seating the bullet on a few rounds. You stated you didn't think it was a problem, but if you don't know what it is, that statement has no meaning. Determine the neck tension and then you'll know with certainty. Even if the neck tension only happens to be in the .003" to .004" range, that may be enough to promote formation of the bullet nose ring you described. Excessive neck tension can also be associated with seating depth variance.

Second, nose rings from seating die stems are not at all uncommon. I use Redding Type S Match die sets and the majority of the seating die stems required some attention to address the ring issue. The ring is caused by the hard steel bevel around the inside of the seating die stem mouth as it pushes on the much softer copper jacket of the bullet ogive during the bullet seating process. Perhaps more correctly,



I believe it is caused by the bottom edge of the bevel. The image above is a VLD seating die stem for a Redding .223 Rem seating die. Although not the best image, one can see this "edge" at the bottom of the bevel where it meets the inner wall of the stem in a very abrupt transition. I believe it is this "edge" or "transition" from the bevel to the wall that may not align particularly well with a specific bullet ogive that actually causes the ring. This is not abnormal. The die manufacturer has no way of knowing the ogive radius of the bullets selected by the end user, and so the shape of the bevel is a compromise. If the surface of the bevel doesn't seat relatively flush against the bullet ogive during the seating process, that edge can indent the soft copper jacket, thereby causing the nose ring you described. This ring is typically found about 1/4" to 3/8" below the meplat, but its location will vary somewhat according to the specific bullet design. Some die manufacturers such as Redding offer Standard and VLD stems for bullets with different nose length, but there is no way they can offer stems to match the ogive radius of every bullet a user may wish to seat.

When I encounter a stem that is leaving nose rings (and it really takes very little pressure on the ram for this to happen if the bevel-ogive alignment isn't right), I will put the stem in a drill chuck, and insert a small cone-shaped piece of extra fine steel wool, then polish away until the bevel edge is somewhat rounded off/polished and no longer leaves the mark. The point is not to try to change the bevel itself, which is not really possible with this approach, but simply to smooth off that sharp edge at the bottom of the bevel where it transitions into the stem body wall. In my hands, this ususally does the trick with respect to minimizing nose rings. However, the more neck tension one uses, the greater the odds that nose rings will be the result, as I noted above. So determine your neck tension and if necessary, adjust it.

Third, in my hands the majority of seating depth variance typically arises from bullet nose length variance. As shown in the image below, both of the critical contact points for maintaining unifrom seating depth lie on the bullet ogive (nose). These two points entail the point where the seating die stem contacts the



bullet ogive just below the meplat (i.e. where the nose "rings" form), and the point at which the caliper insert seats just above the top of the bullet bearing surface. Bullet nose length variance between these two points WILL cause seating depth variance. So the question then becomes, how does one actually sort bullets to address this issue?

The best method would be to use a tool such as Bob Green's Comparator, which is designed to sort bullets based on length variance between these two critical contact points. However, one has to have Bob's tool or something similar from another manufacturer to do that. An alternative approach is to sort bullets by OAL. This is what I would refer to a "poor man's approach", meaning one doesn't have to buy the tool in order to do it. However, it does require some up front analysis and is rather crude compared to sorting bullets with Bob Green's tool. I have taken many bullet measurements over the years and have noticed that the specific Berger bullets I use most often seem to have very little base-to-ogive length variance. In other words, the majority of overall length variance (OAL) lies in the nose region of the bullet, which is not surprising given the bullet manufacturing process. This is what allows sorting bullets by OAL to act somwhat as a surrogate for using Bob Green's tool, because when the majority of OAL variance lies in the nose region, one is effectively sorting bullets by the distance between the two critical contact points when they sort bullets by OAL. Note: this is only true if a particular brand/type of bullet has very consistent BTO dimensions within a single Lot#. If there is large BTO length variance, it won't work very well. Fortunately, that is very easy to determine by simply measuring some bullets. If they seem consistent in the BTO dimension, one can then try sorting by OAL to see whether it may improve seating depth consistency. It really doesn't take much effort to determine whether this approach will offer any benefit.

 

[TaperPin]

I wrap the tip of a bullet with one layer of thin 400 grit sandpaper and spin it in the seating die by hand or drill to polish out the ridges.

As others have probably said already, fresh brass seat harder than fired brass, so that might help consistency .001” and the seating stem smoothing may help half a thou. If you culled a few of the longest and shortest that is probably .001” to .002” of the variation.

Does it make a difference? Shoot your culls to test it.

 

[Chris Edmondson]

Or neck tension too tight requiring more seating force and causing the ring. For me i had tight necks in my wsm and my 257 bob. The berger vld would get a ring seating the wsm until i went to a bushing die and opened up neck. The 257 i use sierra gamechangers and they are soft enough that the jacket collapses at the ring/contact point. Im trying a new die set for that and have lubed bullets before seating with the old die set and eliminated the ring

The picture below is of a Hornady .264 BTHP bullet which, when seated, posted a peak ram force of just 30lbs; that's not much. The 6.5 Creedmoor brass had been fired and resized 10 times already, fully exercised. The die is an LE Wilson, K&M Arbor press. The bullet isn't damaged, nor can the ring be felt using the fingernail test, but a slight ring is there. I haven't done any sort of testing to see where bullets are materially affected when seated under varying degrees of neck tension, other than I know 150lb peak will ruin the bullet .

Maybe a good winter project .

 

[Lead Slanger]

I appreciate all the replies. I know the seating stem needs worked over a little. It's an easy fingernail catching groove it's leaving. I'll lap it in and check my neck tension to know for sure what I'm dealing with and report back.