Interesting phenomenon

[Tokay444]

Hi gang. I'm relatively new to the forum, and fairly new to reloading as well. I have been doing quite a lot of reading and little bit of posting. I'm a machinist by trade and my brain works very mechanically and systematically, and as such, making my own ammo is right up my all as much as shooting it is.
I'm having a weird phenomenon with a Mighty Armory Gold Match die for 6.5 Creedmoor.
I had been, and have now switched back to using a Redding Comp die set with a bushing neck die and body bump die, with excellent results, but adding in an expander mandrel for final sizing.
I will say I have not emailed Wayne about this, and it’s not my intent to point fingers at the die. It’s a very stout unit and a very nice design. I’m still in the problem solving phase and hope to not even bother Wayne at all. Especially being cross border in Canada.
The first anomaly was that the die bottomed out on my shell holder before I could get my .002” shoulder bump that I do with my Redding die. No big deal. I faced .020” off my shell holder and got the bump I needed. The die does run extremely smooth and measured concentricity is every bit as good as advertised.
The issue I’m still troubleshooting is shoulder sooting that I’ve never gotten with any factory ammo or ammo I’ve made with my previous die setups. It’s weird. I have the same headspace measurements that I achieve with my Redding die. I even used two different size comparators to check different datums on two cases sized with each die, and they’re the same, so it’s not a shoulder angle issue the best I can tell without going to an optical comparator. I thought perhaps because the Redding neck bushing die doesn’t size all the way down the neck, and the body die doesn’t touch the neck at all, maybe that unsized portion was acting to seal the chamber, and the new die was sizing that portion now, but if it is, it’s only minutely, and not an amount I can decipher with calipers. Also, factory ammo has never sooted the shoulder. I thought maybe because my Lapua brass has been sized with the Redding dies so many times, perhaps I should just keep them married to each other, so I shot some Berger factory ammo and resized that with the Mighty Armory die, but it still neck sooted. Research says my loads may be light, or my brass may need annealing. I’m running 42.5gr of H4350 behind Berger 140 Hybrids and running 2820-2850 FPS, and anneal every firing.
Removing the expander and running my previous mandrel through instead, had no effect on neck sooting. I don't think the Mighty expander is pulling on the shoulder and causing some weird change in geometry that I can’t determine with my caliper. I feel the last thing to try is a different chamber with once fired brass then run through the Mighty Armory die.
I know that if I email Wayne he’ll probably have suggestions for me. I don’t doubt his level of service for a second, but I pride myself on being a problem solver of these sorts in my day job, so I can’t throw in the towel yet, but I can ask for help from those more experienced in this field than I.
All that said, I cannot say definitively that this shoulder sooting is even an actual problem. My ES are greater as one may expect with more pressure leaking back behind the case mouth, but out to 300 yards, I haven’t really measured much of an accuracy difference.
Sorry for such a long winded post. I hoped to share as much detail as I have right off the hop.
Thanks in advance.

 

[Dave Marshall]

Some soot on the neck/shoulder is really not an issue. If it’s accurate and velocity is acceptable, I wouldn’t give it a second thought. Excessive soot down the case body could indicate low chamber pressure.

It could also be as simple as different powder formulation from whatever is used in the factory loads you were using before.

 

[FeMan]

It sounds like you are definitely not getting a good/quick seal on the neck. How much neck clearance are you running? The load sounds like it has enough pressure where I wouldn't suspect that being a real issue. Hard brass and excessive neck clearance can contribute to what you are seeing. I usually go for 0.004 clearance but my buddy has a 6.5CM die with a tight neck (0.002" clearance) and it shoots great. That along with very minor differences in die dimensions might be the issue.

Also, how are you measuring shoulder set back? The best is with the chamber by sizing a little more each time until you just get a clean bolt drop. Comparators aren't always perfect in measuring setback.

You said you measured cases, but I have a similar issue with a 223 upper in my AR. The issue there is the dies over size the body right at the shoulder and unless I shoot them right at max pressure, I get sooted bodies (not just shoulders).

Hope that helps.

 

[Tokay444]

Some soot on the neck/shoulder is really not an issue. If it’s accurate and velocity is acceptable, I wouldn’t give it a second thought. Excessive soot down the case body could indicate low chamber pressure.

It could also be as simple as different powder formulation from whatever is used in the factory loads you were using before.

I am fine to take you at your word on it not being a big deal, but all else being equal on my reloads besides the die being used, Redding produces only neck sooting, but Mighty Armory produces shoulder sooting.
Thank you for your reply.

 

[Tokay444]

It sounds like you are definitely not getting a good/quick seal on the neck. How much neck clearance are you running? The load sounds like it has enough pressure where I wouldn't suspect that being a real issue. Hard brass and excessive neck clearance can contribute to what you are seeing. I usually go for 0.004 clearance but my buddy has a 6.5CM die with a tight neck (0.002" clearance) and it shoots great. That along with very minor differences in die dimensions might be the issue.

Also, how are you measuring shoulder set back? The best is with the chamber by sizing a little more each time until you just get a clean bolt drop. Comparators aren't always perfect in measuring setback.

You said you measured cases, but I have a similar issue with a 223 upper in my AR. The issue there is the dies over size the body right at the shoulder and unless I shoot them right at max pressure, I get sooted bodies (not just shoulders).

Hope that helps.

Yes, that does help a bit. When I pin gauged the neck on this barrel it came out to .298". My loaded rounds are .2915-.292", so there may be some merit to the excessive clearance, but I would think that would mean factory ammo running less stout loads would suffer more. Also, it doesn't explain why the Redding dies don't produce the same effect, unless perhaps the "donut" is sealing the shoulder off? But that brings me back to, "why doesn't factory ammo do it?".

 

[Dave Marshall]

I am fine to take you at your word on it not being a big deal, but all else being equal on my reloads besides the die being used, Redding produces only neck sooting, but Mighty Armory produces shoulder sooting.
Thank you for your reply.

I understand better now, I think.

The gap in the Redding die at the neck shoulder junction could easily be the cause. I’m not sure if there’s any way to test this that isn’t just anecdotal though.

 

[Straightshooter1]

Hi gang. I'm relatively new to the forum, and fairly new to reloading as well. I have been doing quite a lot of reading and little bit of posting. I'm a machinist by trade and my brain works very mechanically and systematically, and as such, making my own ammo is right up my all as much as shooting it is.
I'm having a weird phenomenon with a Mighty Armory Gold Match die for 6.5 Creedmoor.
I had been, and have now switched back to using a Redding Comp die set with a bushing neck die and body bump die, with excellent results, but adding in an expander mandrel for final sizing.
I will say I have not emailed Wayne about this, and it’s not my intent to point fingers at the die. It’s a very stout unit and a very nice design. I’m still in the problem solving phase and hope to not even bother Wayne at all. Especially being cross border in Canada.
The first anomaly was that the die bottomed out on my shell holder before I could get my .002” shoulder bump that I do with my Redding die. No big deal. I faced .020” off my shell holder and got the bump I needed. The die does run extremely smooth and measured concentricity is every bit as good as advertised.
The issue I’m still troubleshooting is shoulder sooting that I’ve never gotten with any factory ammo or ammo I’ve made with my previous die setups. It’s weird. I have the same headspace measurements that I achieve with my Redding die. I even used two different size comparators to check different datums on two cases sized with each die, and they’re the same, so it’s not a shoulder angle issue the best I can tell without going to an optical comparator. I thought perhaps because the Redding neck bushing die doesn’t size all the way down the neck, and the body die doesn’t touch the neck at all, maybe that unsized portion was acting to seal the chamber, and the new die was sizing that portion now, but if it is, it’s only minutely, and not an amount I can decipher with calipers. Also, factory ammo has never sooted the shoulder. I thought maybe because my Lapua brass has been sized with the Redding dies so many times, perhaps I should just keep them married to each other, so I shot some Berger factory ammo and resized that with the Mighty Armory die, but it still neck sooted. Research says my loads may be light, or my brass may need annealing. I’m running 42.5gr of H4350 behind Berger 140 Hybrids and running 2820-2850 FPS, and anneal every firing.
Removing the expander and running my previous mandrel through instead, had no effect on neck sooting. I don't think the Mighty expander is pulling on the shoulder and causing some weird change in geometry that I can’t determine with my caliper. I feel the last thing to try is a different chamber with once fired brass then run through the Mighty Armory die.
I know that if I email Wayne he’ll probably have suggestions for me. I don’t doubt his level of service for a second, but I pride myself on being a problem solver of these sorts in my day job, so I can’t throw in the towel yet, but I can ask for help from those more experienced in this field than I.
All that said, I cannot say definitively that this shoulder sooting is even an actual problem. My ES are greater as one may expect with more pressure leaking back behind the case mouth, but out to 300 yards, I haven’t really measured much of an accuracy difference.
Sorry for such a long winded post. I hoped to share as much detail as I have right off the hop.
Thanks in advance.

Your load is not light, so you can ignore that as something that may be contributing to the sooting. Sooting to the neck it quite normal and even sooting to the neck to some extent is not unusual. Like, in my case with my .308, I get soot all the time on the necks (not heavy soot) and none below the neck.

A picture of your cases would help us have a better idea.

A pic is worth a thousand words

Here's a pic of my Lapua brass that's been fired 15X times. They're annealed after every firing, and were neck turned after fire forming and I use a Lee Collet Die to size the necks then bump the shoulder, so I'm not doing anything to the case body.

 

[Tokay444]

I understand better now, I think.

The gap in the Redding die at the neck shoulder junction could easily be the cause. I’m not sure if there’s any way to test this that isn’t just anecdotal though.

That was also inline with my theory as to why the Redding setup doesn't do it, and what made me try a few factory loaded ammos, only to have them no do it either until I reloaded that brass with the Mighty die.

 

[Tokay444]

Your load is not light, so you can ignore that as something that may be contributing to the sooting. Sooting to the neck it quite normal and even sooting to the neck to some extent is not unusual. Like, in my case with my .308, I get soot all the time on the necks (not heavy soot) and none below the neck.

A picture of your cases would help us have a better idea.

A pic is worth a thousand words

Here's a pic of my Lapua brass that's been fired 15X times. They're annealed after every firing, and were neck turned after fire forming and I use a Lee Collet Die to size the necks then bump the shoulder, so I'm not doing anything to the case body.
View attachment 1230048

I should have known better than to come to the internet without pictures!
but imagine your neck soot, all the way back to the body/shoulder junction.

 

[FeMan]

Yes, that does help a bit. When I pin gauged the neck on this barrel it came out to .298". My loaded rounds are .2915-.292", so there may be some merit to the excessive clearance, but I would think that would mean factory ammo running less stout loads would suffer more. Also, it doesn't explain why the Redding dies don't produce the same effect, unless perhaps the "donut" is sealing the shoulder off? But that brings me back to, "why doesn't factory ammo do it?".

That's more neck clearance than optimal. It may be a contributor. From what you describe, the only difference is in the die used; not in neck tension, work hardening, brass thickness, case capacity, etc.

It sounds like it may be what you guessed; the Type S bushing die does not size to the neck/shoulder junction. The extra width allows the case to seal faster than one with a fully sized neck. Factory ammo may have different pressures, powders, softer brass, etc. that combines to provide a good seal.

 

[Tokay444]

This is typical of what I get with MA die.

 

[Tokay444]

Sized with Redding dies.

 

[Tokay444]

And lastly, factory Berger ammo.

 

[FeMan]

FWIW, my Dasher case shoulders are starting to look a lot like the top picture. They have 12 firings and the with the 40 degree shoulder it tough to get enough heat into them with my flame annealer to get a good seal.

 

[Tokay444]

Before I pull this barrel in favour of the last one, I'll try annealing the factory Berger Lapua brass a little longer than my normal setting, and sizing 10 with the MA die, and 10 with the Redding die.

 

[chromatica]

I'm going to take a different tack. I think neck tension is the culprit. If you don't have enough neck tension, the pressure won't build up high enough in the case to seal the neck before the bullet releases. I'm going to guess that your MA die isn't squeezing the neck enough. Even though you are using an expander mandrel in both cases, there is springback to consider. Measure the outer diameter of the necks before and after expanding with the mandrel with the two processes and tell us the results.

 

[chromatica]

Also, try changing your plan of annealing every firing. Annealing softens the brass and will have the effect of giving less neck tension.

Can you put a smaller bushing in your MA die?

 

[Tokay444]

Also, try changing your plan of annealing every firing. Annealing softens the brass and will have the effect of giving less neck tension.

Can you put a smaller bushing in your MA die?

I can't. It's a one piece full length, but it's neck and expander dimensions mirror my Redding setup.
What I will try is removing the expander, and not using the mandrel.

 

[Tokay444]

Heading out now to try about 3 thou more neck tension on ammo loaded with the MA die by taking the expander out.
This will be with once fired Lapua brass from the Berger factory ammo. I did not anneal this load.

 

[Tokay444]

Marginal improvement if any.
I will try the other 10 cases from the box with the same process, but add annealing back into the mix.
The added neck tension did not seem to have any negative effect on my ES/SD.
If I can’t get the shoulder sooting to cease, in the spring I’ll load up 50 of each method and shoot for groups to try and determine if it actually make a difference on target, or if I’m just being too anal retentive about how the case looks when it comes out of the chamber.