.40 Bullet / Case Concentricity Problem

[reidry]

I've been reloading for 10 years now and it seems that my .40 loads always give me the most rejects out of all the calibers I currently load and have loaded in the past.

The equipment - I'm running a Dillon 1050, 1st stage is case pickup, 2nd stage is a Dillon Carbide sizing die, 3rd stage is a shortened Dillon Carbide sizing die (I just ordered an EGW undersize to replace this one), 4th is prime, 5th is powder drop/bell, 6th is empty, 7th is Dillon Seating Die, 8th is Lee Factory Crimp Die.

OAL is 1.197, crimp is .421, bullets are STAR jacketed open lead base. (I know STAR is out of business but I still have a few thousand ...)

Between 8 and 11 of every hundred will not case drop. The biggest problem I'm fighting is a bullet concentricity issue. When I drop the case in the Wilson gage it will drop down until the bullet reaches the throat step. The side of the bullet then rubs the throat step hard. Some can be pushed in with light thumb pressure, others refuse to go at all. They all drop in the case gage backwards, so it's not a bulged brass issue. If I pull the barrel from my gun, the rounds will drop in the chamber without issue.

I cleaned all my dies to ensure this wasn't a crud buildup problem (didn't think so because it's always been this way). Checked the seating operation and found that I was getting a half moon mark in the top of the bullet. I removed the seating widget from the die and found it had a little burr around the axial hole. I polished the inside of the seating stem and then checked the fit of the truncated cone bullet. Seemed that I wasn't getting much help from the tapered sides in aligning the bullet. I indicated the seating stem in my Bridgeport, used an endmill to move the seating face .040 deeper to allow the tapered walls to straighten the bullet more before contacting the flat forcing portion of the stem. This seems to have improved things slightly but not completely. I now have a faint ring or almost complete ring on the top of each bullet after seating.

Is the Wilson case gage too rigid in the throat area? Should I be using a different gauge? Is there something else I should check in my setup?

Thanks in advance.

Ryan

[Larry White]

Redding competion seating die is your answer, your reject rate will drop to less than 1%. I use a lee u die by EGW, the redding comp seater and a dillon crimp. I was haveing rejects about like yours and they just went away with the redding. I think that with the u die you dont need the fcd, I think it over works the case and sizes the bullet. Last batch was 500 and I tossed 2.-----Larry

[cautery]

Hey... Finally, a thread I should be able to make a substitive contribution to... I have done a lot of work with the .40 round.... even had some custom chambered barrels made...

A caveat... I have a 550B not a 1050, but I'll offer my observations anyway...

Let me ask some questions first... When you say the bullet rubs on the "throat step hard".... Is the head striking the headspacing step or is it contacting the straight walled lead area, or is the bullet actually touching the tapered "throat".

I don't have my case gauge handy, but I don't remember mine even having the tapered throat per say... (I don't use a case gauge very often.... I tailor my rounds to individual barrels)

Can you post a pic of one of the offending rounds.... preferably a profile pic, and one from directly overhead...

I can remark about a couple of things...

1) 0.421" crimp... The SAAMI spec for the 40 S&W crimp is 0.423". I know 0.002" doesn't sound like a lot, but the round is "supposed" to headspace via the front face of the case on the step in the chamber. Overcrimping reduces the headspacing bearing area, but more importantly, you run the risk of deforming the projectile, and possibly causing something weird to happen to the case wall.

2) I don't know what pistol model or barrel make you are using, but the typical beginning point for the throat is 0.155" forward of the headspacing step (or 1.05" from the breech face, assuming a 0.850" breech to step chamber length). You have to have a really long round to have a problem hitting the actual throat on a standard barrel... I don't even think your exceptionally long 1.197" rounds would do so on a stock chamber (1.135" max SAAMI spec; 1.125" typical OAL) I used to load to 1.140 in my custom, short-lead, barrel and had no head contact EVER in the throat/lead/step.

*** Is it possible that your shell plate and/or your tool head is/are tilting some, thus causing the head to seat out of alignment?

Typically, the only way for a bullet to hit one side of the step/lead/throat (whatever)... is that it is seated at a cant to the long axis of the round.

That is most definitely possible if the tool head and or shell plate are cocking due to more pressure on one side than the other coupled with mechanical play... And the longer the round, the more pronounced this will be... especially with reduced seating depths.

Are the cases indexing vertically under the seating die... meaning, is it possible that the case may be riding out toward the outside of the shell plate?

That "faint ring" you see now.... Is it concentric to the projectile outer diameter when viewed from the end? Or is it off-center to one side?

Die makers do a fair job of making "general" seating stem profiles to cover the vast majority of bullet profiles... But I too have noticed that the Dillon seating stem (and other dies too) just doesn't seam to fit truncated cone 0.400 bullets very well.

I modded one to fit the bullets I have/was using, and it works well... As you saw, it helped you too...

Ideally, IMHO an ideal seating stem would exactly match the bullet profile such that you had 100% contact with the cone portion of the bullet... NOT just a ring. It should NOT however contact the flat portion of the tip...

Does your seating stem have concentric machining "steps" visible n the sloped portion? Most do due to the machine that cuts them not having the resolution, or the resolution not being programmed into it, to cut smooth transitions.

I'm toying with the idea of casting seating stem inserts using actual bullets to get "perfect matches"... Making them out of a polymer that won't deform the jackets too.

Does this happen JUST on that brand of bullet, or does it happen with other .40 cal bullets as well?

More later...

[ErikW]

Do what Dillon says and leave each die loose, tightening its locknut only when you have a case or round in it.

[reidry]

First, thanks for the quick replys.

Redding competion seating die is your answer, your reject rate will drop to less than 1%. I use a lee u die by EGW, the redding comp seater and a dillon crimp. I was haveing rejects about like yours and they just went away with the redding. I think that with the u die you dont need the fcd, I think it over works the case and sizes the bullet. Last batch was 500 and I tossed 2.-----Larry

<{POST_SNAPBACK}>

I've thought about the Redding Comp Seater, that one has the micrometer adjustment right? Would be nice to be able to adjust seating depth without fiddling with the locking ring. What does the Comp Seater cost?

Hey... Finally, a thread I should be able to make a substitive contribution to...  I have done a lot of work with the .40 round.... even had some custom chambered barrels made...

A caveat...  I have a 550B not a 1050, but I'll offer my observations anyway...

Let me ask some questions first...  When you say the bullet rubs on the "throat step hard"....  Is the head striking the headspacing step or is it contacting the straight walled lead area, or is the bullet actually touching the tapered "throat".

<{POST_SNAPBACK}>

The Case gage doesn't have a throat. It has the case area, the headspacing step then a .401 cylindrical area that extends forward to the end of the gage. Very simplified when compared to an actual barrel. The sides of the bullet are touching the sharp leading edge of the headspacing step. Contact begins at or below (further toward the primer) the bottom of the cone of the bullet nose where the bullet becomes cylindrical.

I don't have my case gauge handy, but I don't remember mine even having the tapered throat per say...  (I don't use a case gauge very often....  I tailor my rounds to individual barrels)

Can you post a pic of one of the offending rounds.... preferably a profile pic, and one from directly overhead...

I can remark about a couple of things...

1) 0.421" crimp...  The SAAMI spec for the 40 S&W crimp is 0.423".  I know 0.002" doesn't sound like a lot, but the round is "supposed" to headspace via the front face of the case on the step in the chamber.  Overcrimping reduces the headspacing bearing area, but more importantly, you run the risk of deforming the projectile,  and possibly causing something weird to happen to the case wall.

2) I don't know what pistol model or barrel make you are using, but the typical beginning point for the throat is 0.155" forward of the headspacing step (or 1.05" from the breech face, assuming a 0.850" breech to step chamber length).  You have to have a really long round to have a problem hitting the actual throat on a standard barrel...  I don't even think your exceptionally long 1.197" rounds would do so on a stock chamber (1.135" max SAAMI spec; 1.125" typical OAL)  I used to load to 1.140 in my custom, short-lead, barrel and had no head contact EVER in the throat/lead/step.

*** Is it possible that your shell plate and/or your tool head is/are tilting some, thus causing the head to seat out of alignment?

<{POST_SNAPBACK}>

I'm using a custom STI built by Millenium Custom, Schuman Ultimatch barrel (non AET). I can reduce the crimp, but all the folks around here seem to be running .419 to .420. However I don't think this is the root of my seating problem.

If I'm getting misalignment in the press it's got to be in the head, the shell plate is very rigid on a 1050 and basically locks down against the frame of the machine when sizing and seating is happening.

Typically, the only way for a bullet to hit one side of the step/lead/throat (whatever)... is that  it is seated at a cant to the long axis of the round.

That is most definitely possible if the tool head and or shell plate are cocking due to more pressure on one side than the other coupled with mechanical play... And the longer the round, the more pronounced this will be... especially with reduced seating depths.

Are the cases indexing vertically under the seating die... meaning, is it possible that the case may be riding out toward the outside of the shell plate?

That "faint ring" you see now.... Is it concentric to the projectile outer diameter when viewed from the end?  Or is it off-center to one side?

Die makers do a fair job of making "general" seating stem profiles to cover the vast majority of  bullet profiles...  But I too have noticed that the Dillon seating stem (and other dies too) just doesn't seam to fit truncated cone  0.400 bullets very well.

I modded one to fit the bullets I have/was using, and it works well...  As you saw, it helped you too...

Ideally, IMHO an ideal seating stem would exactly match the bullet profile such that you had 100% contact with the cone portion of the bullet... NOT just a ring.  It should NOT however contact the flat portion of the tip...

Does your seating stem have concentric machining "steps" visible n the sloped portion?  Most do due to the machine that cuts them not having the resolution, or the resolution not being programmed into it, to cut smooth transitions.

I'm toying with the idea of casting seating stem inserts using actual bullets to get "perfect matches"...  Making them out of a polymer that won't deform the jackets too.

Does this happen JUST on that brand of bullet, or does it happen with other .40 cal bullets as well?

More later...

<{POST_SNAPBACK}>

The faint ring I'm seeing is from the axial hole in the seating stem of the dillon die. It is concentric with the round i.e. centered on the nose of the bullet. My seating stem is contacting the bullet on the flat and probably only on the flat. I can releave the flat portion more so that the tapered portion contacts the cone portion of the Truncated Cone bullet but I wasn't sure that was the right method for engagement.

I haven't tried any other bullets lately, but I've got some Rainers I'll try this evening. I'll also pick up some zero's from the local supplier since that will probably be my next batch.

The seating stem did have rings on the conical portion. I've polished them a bit to smooth that surface.

Do what Dillon says and leave each die loose, tightening its locknut only when you have a case or round in it.

<{POST_SNAPBACK}>

I'll give that a try too.

Thanks,

Ryan

[Larry White]

Ryan, yes its the one with the mike on top, and the abilty to change oal quickly is a nice feature. But it does the best job of bullet seating I've seen. Probaly 50 or 60 bucks. I got mine off a prize table but would buy one in a heart beat.------Larry

[.40AET]

I had bullet interference problems when drop checking at one time. I had changed brands and the new ones wouldn't pass the gauge. I was loading 1.200" oal and changed to 1.160 oal. Everything passed the gauge with the shorter oal. I went back to my usual brand and the problem went away. Try making a couple of shorter ones and see what happens, or change bullets.

BTW- I contacted Lee a few years back. They will custom make a seater stem based on the bullet you send them with your die. I'm running a full set of Lee dies. I never got around to it, but it sure sounded good.

[cautery]

You're right... it's not likely the crimp... Just making an observation. I've always been taught that the crimp should be the minimal one that straightens the case wall, and my experience bears this out via accuracy check. Perhaps the extra 0.002" doesn't deform the bullet, I don't know... Anyway...

As the other guy said, the Redding Comp seater die is a great idea regardless of whether it fixes THIS problem. I have one and like it a lot.

Wow... if the bullet is striking the headspacing step, you either have some seriously messed up bullets, or the bullet should be visibly crooked in the case I would think...

Have you mic'd a bullet? Mic one that hasn't been seated... Measure max diameter every 60 degrees and record... They should all be very, very close.

Now, use a kinetic bullet puller to get a seated bullet out of a failed round... Measure same way... Are the tolerances the same or different...

Maybe it's just as simple as 8+ bad bullets per hundred... If they are different, then you MIGHT assume loading the bullet causes the distortion... but the only way to REALLY verify is measure a bunch of bullets to make sure they are good, and then seat them in sequence til you get a failure... No failures= bad bullets... All fail= loading distortion of bullet.... partial fail = study some more.

I'm a weirdo on a LOT of things... One of them is that I don't use open base jacketed bullets.

[reidry]

I'm a weirdo on a LOT of things...  One of them is that I don't use open base jacketed bullets.

<{POST_SNAPBACK}>

Whose bullets are you using? Locally I can get West Coast plated bullets, Rainier plated bullets or Zero Jacketed. The Zeros have the open base.

My investigation continues but I have a new very interesting data point. I picked up dillon stainless steel case gage at my local reloading shop yesterday. Every round rejected by my Wilson gage drops freely into and out of the Dillon gage.

The area forward of the headspacing step measures the same between the two gages while the case head area is .002 larger in the Dillon gage. Tonight I'm going to pull my barrel and measure my chamber. I don't have access to dial bore gages or I'd profile all three at various depths.

More to follow...

Ryan

[Nolan]

A quick and dirty check for case gauges. If a fired case will not fit the case gauge the gauge is smaller than your chamber. If a fired case fits the case gauge use a different case gauge.

Nolan

[reidry]

And now "the rest of the story" ...

Took my STI apart (needed a good cleaning anyway) and checked the dimensions of the chamber. Here are all my measurements:

Wilson case gage: .425 (might be .4255)

Dillon case gage: .427

Schuman Barrel: .427

Of the bullets I have on hand here are their measurements:

STAR: .400

Gold Dot: .400

West Coast: .401

Rainier: .402

The Rainer's will not gravity drop in the Wilson gage. The Dillon gage doesn't like them much better and dummies don't hand cycle as smoothly as the others. West Coast have a rounder cone area and a smaller flat point, these seem to case drop very well in both gages. Gold Dots are also rounder but not quite as steep or as long as the West Coast. The Gold Dots drop well in both gages. The STAR bullets have a large flat nose, a short cone and a long straight bearing surface. The Dillon gage likes these, my barrel likes these and the Wilson gage only likes 90% of them.

For now I'm going to shoot up the STAR bullets I have on hand and use the Dillon gage. If I have any burps I will be careful to capture the offending cartridge and check it completely against both gages and the barrel.

Anyone want some Rainer bullets?

Thanks,

Ryan

[wide45]

I was never happy with the .40 dillon seating die. The flat ended cavities would not center the bullets.

I swapped in a RCBS seating die with a seating stem for round nose. I think I may have had to borrow the stem from a different caliber die.

It has worked great for every shape of bullet I've tried.