Case Neck Concentricity

[ElmerThud]

You know... There are dies with NO expander ball? Just neck size the brass...
Works great. Regards, Guy

Presumably in a neck sizing die rather than F/L die?
Or, in a F/L die so the shoulders are bumped back?

Does that work if you just remove the decap expander/rod from the die Guy?

I haven't ever thought of that, but would kind of guess bullet seating could be tight?

I'll have a go & see what happens when I next have a couple of fired cases. Mine are all now resized or reloaded.

@ Darkhorse - Nope, personally my ammunition consistency & accuracy is excellent for hunting, which is 'my thing', so I have never & don't intend to bother case neck turning.

I absolutely know I could take a red stag out to 400yds, but never would. I regard 300-320 as absolute max & then, only if it's really necessary. I'd much rather stalk in closer and take a 100-200 yd shot. Field craft. That's the key.
Cheers, ET

 

[Guy Miner]

Just using a neck-sizing die for several rifle cartrides. Bushings, which can be changed to control how tight the neck is.

Guy

 

[ElmerThud]

Just stretching this thread to a specific issue I'm experiencing re bullet concentricity...

Recently I started reloading for my M1903 Mannlicher Schoenauer and while I can easily get to +/- .0005" concentricity on the case necks, the bullet cty is a very different matter and is inconsistent varying between .0025 & .005".

Nothing I do seems to improve matters. This is with the Hornady 160gn RN Interlock bullet.

Modern collar or collet dies for this cal/cartridge aren't available, so I use both Redding & RCBS dies.
Any practical suggestions?
I've tried using an expander die to aid matters, but no difference I can see.
Cheers, ET

 

[jimbires]

I'm assuming the bullet being a round nose is also a flat base . I'd try cutting a nice inside chamfer on the inside of the case mouth and dipping the bullet base in powdered graphite . I'd use the vld chamfer tool , I think it's 22* . I have one made by Lyman . this will give a nice longer slower angle to help get the bullet to start straight .

 

[ElmerThud]

I'm assuming the bullet being a round nose is also a flat base . I'd try cutting a nice inside chamfer on the inside of the case mouth and dipping the bullet base in powdered graphite . I'd use the vld chamfer tool , I think it's 22* . I have one made by Lyman . this will give a nice longer slower angle to help get the bullet to start straight .

I'll certainly give these a go jb, I've tried all I can think of.
The bullet is a flat base, so I do use a neck expander die.
Cheers, ET

 

[kraky1]

I'm another lover and user of low angle Deburrers.... they do help me seat my bullets straighter. If you get one I think you will immediately feel a much smoother transition of the bullet heel into the case mouth.

 

[ElmerThud]

Having inspected both my seating dies stems/rods, I conclude I must amend my die choice for each bullet type.

I have used the RCBS seating die with the 160gn RN & the Redding seating die with the 140 gn SST bullet. - WRONG!

The Redding die has a much broader flatter seating cone, definitely in line with the profile of the 160gn RN, where the RCBS is narrower & more designed for 'pointy' bullets. So now, the RCBS seating die can be allocated to the SST bullet & the Redding to the 160gn RN.

Resetting the most suitable seating dies for each bullet choice is my first move to improve matters.

In checking further, I found the Redding MSch die doesn't have a 'roll crimp' facility which the RCBS does. I guess it's not so much of an issue as I now have a custom Lee FCD, so can use that.

First moves in trying to sort out the bullet runout, the rest will follow. Thanks chaps.
Cheers, ET

 

[jimbires]

if I were you , I'd check runout before the crimp , then again after crimping . this could be the problem .

 

[ElmerThud]

if I were you , I'd check runout before the crimp , then again after crimping . this could be the problem .

Thanks Jim. I have already checked this and there was no difference at all.
I haven't yet loaded any rounds with the dies switched, but shall most certainly do that again very soon.
Cheers, ET

 

[Darkhorse]

Elmer, I use inline bullet seating dies for all my rifle loading. These have tightened up my grouping a good bit and I feel contribute to a more concentric round. Small gains add up to larger gains.

 

[ElmerThud]

In this case, I can't use 'in line' dies (not that I use them anyway though) Darkhorse, They're not available for my old Mannlicher Schoenauer & would have to be custom made.

For my other rifles I get on just fine with the dies I have & concentricity is not an issue.
When I resize, case neck runout is not more than +/- .0005" and that's easily good enough.
I put that runout down to brass thickness variation.

The problem has only been with the alignment of the 160gn bullet for my 1922 MSch. M1903 in 6.5x54. It's a specific issue & advice from you guys is always helpful.

I may well be on the road to resolving the problem now; I identified the seating stem difference & took Jims suggestion, I ordered the Lyman VLD chamfer tool to aid matters.
We'll see how I get on with the change & using the tool when it arrives.
Cheers, ET

 

[kraky1]

I've found over time if a seating stem pushes on the very tip of the bullet my runout is screwed. It's an upside-down balancing act gone bad!

 

[ElmerThud]

Here am I completely frustrated!
I've been banging on about how wonderfully concentric my reloading has been & all this is true.

This morning I've been finishing prepping & charging my .25-06 loads. Not many rounds, just 20.
All has gone well with case neck concentricity not exceeding on any case, .0005" Magic! All in order.

I open a new box of Nosler 110gn AccuBond bullets, carefully seat the first three bullets using my usual seating die - an RCBS Competition die, then measure concentricity.
Shock! They read a .010" runout.

I double check everything, remove the bullet, resize the case and check the neck runout..good at .0005", recharge and re-seat a new bullet and find the runout at .006"
So, I open another box of Nosler bullets from the same batch...lo & behold, runout exceeding .009"

Now I've stopped in complete frustration, checked .25-06 ammunition loaded last week with a similar Nosler 110gn AB from a different batch and they read bang on .0015" runout, with two reading .002".

This is just so frustrating. I cannot find anything has changed with the die, it's the same die I've used for the last fourteen years & appears just fine.

Suggestions what to do? no point loading more with these bullets, not that I can see or measure anything wrong with them, but can't see how the alignment can be so bad.

PS.... just had two plastic white tips break off as I took the bullets from the box - Not good!

 

[TackDriver284]

I would also check the fired case neck runout before sizing to check my chamber trueness to see if its straight and square before sizing it. Take note of measurements before and after sizing to see where the problem lies. If the sized case neck runout measurements is greater than the fired unsized cases, then the problem could be the die setup.

 

[kraky1]

Elmer... take the seating stem out of your die and take one hand and push the bullet into the stem holding the stem in the other hand and see if the stem is contacting the jacket of the bullet or trying to push at the tip of the bullet. If it's pushing at the tip you're screwed. You may have to research a different seating stem from your manufacturer or find somebody who can hone it out.
Regarding tips breaking off this should not be happening there were problems with earlier batches of Nosler AccuBond they shouldn't be happening anymore you could call nosler with your lot numbers and see what they say.... do not hunt those bullets until you get the answer.

 

[ElmerThud]

Thanks for the replies folks. I've done the measurements & don't see anthing strange at all.
I also stripped the seating die and checked bullet fit to stem, that's perfect too, the pressure is all applied to the ogive area, not the bullet point.

I don't 'get' the plastic tips shearing at all...put it down to too much recycled polymer mixed with the virgin polymer. A manufacturing 'error' pretty much without doubt. Surprising it wasn't picked up during QC production monitoring.
It's the kind of thing done to save money! ... I have three boxes from the same batch.

I'm not optimistic about dealers here in UK getting behind this, we'll see.
I'll buy another box of AB's and see if the problem goes away.

 

[kraky1]

I re-read your post closer and see you are using a RCBS competition seating die. I bought my first one of these about a year ago for 308 and it's a universal die and can work with almost any 308 Caliber. To be honest the thing is a piece of crap. I have Hornady Plain Jane seating dies that way out perform the RCBS. It's fun dropping bullets through the window but the results are not good. When I troubleshoot the problem I found the seating stem was indeed pushing on the tip of the bullet. I got a hold of rcbs and they wanted like 25 or $30 to get a better stem for sharper angle profile bullets. that's the price of a most normal die sets. As far as I'm concerned their "competition"dies are pretty much smoke and mirror compared to their normal dies which are pretty good value for the price. I still like RCBS products..... but I think these things are a tin can rip off of their reputation and probably made in China! Hey.?.. did I make it clear I'm not crazy about them...Lol!

 

[bigedp51]

If you want to reduce neck runout and bullet runout then buy a Forster Benchrest 2 die set with their in line seating die.

The Forster full length die has a high mounted floating expander. The expander enters the case neck while it is still held and centered in the neck of the die. This method prevents the expander from pulling the necks off center and inducing neck runout.

The in line seater holds the case and bullet in alignment when seating and reduces any chance bullet misalignment with the case neck.

A full length resized case when loaded is supported by the bolt face in the rear and by the bullet in the throat. The case neck and body of the case do not touch the chamber walls. The ejector in the bolt face pushes the case forward in the chamber until the shoulder of the case contacts the chambers shoulder. Meaning the shoulder of a full length resized case is all that contacts the chamber.

So again the case in the rear is supported by the bolt face and the shoulder of the case and the bullet in the throat center the bullet. Meaning a full length resized case has "wiggle room" for the bullet to self center in the throat.

So you check concentricity by spinning the cartridge on its body and see twice as much bullet runout as it actually has.

Below in the foreground I have a RCBS case mastering concentricity gauge and in the left rear is a Hornady concentricity gauge. The RCBS gauge spins the case on its body and the Hornady gauge spins the case from the bullet tip and the base of the case. The Hornady gauge will read half the runout the RCBS gauge does. And the Hornady gauge holds the case like it will be in the chamber when fired.

Meaning a standard concentricity gauge is checking how straight the entire case is. "BUT" the case body and case neck are not aligning the bullet in the throat because neither is touching the chamber walls.

Bottom line, the military considers that .003 or less bullet runout is match grade ammo. And with the Forster die set you can easily get .001 or less runout with uniform brass.

 

[Rol_P]

I agree 100% with your comments on RCBS Competition Dies.
The Redding Competition Seater die that I upgraded to is generally
Producing much more concentric cartridges in the area of 0.002" or
less on my gauge if I do my part.

 

[ElmerThud]

bigedp51, I'm reading and absorbing what you're saying...might take a short time to fully grasp, but understand the point you make of difference between the two guages.
So, Question: Are you saying the RCBS guage runout reading should be halved?
i.e. a reading of say .006" is really .003"

I'd just point out my F/L resizing die is a standard RCBS die and I resize to 'fired case headspace' dimension at 2.047".
I take the point of the 'high mount' expander ball in the Forster die.
I have adjusted the expander rod in my RCBS die upward, so it just comes through the case neck. That seems to work very well for reducing neck runout significantly.

My actual rifle headspace dimension is 2.049" - I have measured this and am certain of the dimension.
The case neck runout I measure using my Sinclair guage is not greater than .001" & mostly .0005"
so I put the runout down to variation of brass thickness.

My rifle is a break action single shot weapon, so no bolt. It has a semi-fixed locking lug. The firing pin lug can be removed, but it is normally locked in place. (See pics)

It's really the seating die I'm calling into question here and possibly this batch of bullets, although I have no successful means of measuring the possiblity of runout on the actual bullet.
Anyway, I don't want to go to the trouble of getting down the benchrest arbour press route, for me it's just not worth it.

However, Rol_P, I have since yesterday been looking seriously at the Redding Competition Seater die and look set to acquire one as soon as I can find one in the UK. I have asked a dealer to find or order one in for me. Then I will surely see if it gives better results.