NAS3 5.56 Cases - Tikka 223 w/ 88 TMK

[Schmo]

Pretty lame that they are that short.

So yours are 6 thou short compared to new brass. They are intentionally 3-5 thou short to allow case stretch. So you’re barely over that by 1 thou. Carry on

 

[pods8 (Rugged Stitching)]

They are intentionally 3-5 thou short to allow case stretch.

These brass that are once fired and thrown away intentionally allow for case stretch vs being supported? Is that something in the design or sammi spec? I am not in the know, it just seemed counter intuitive as a statement.

 

[wind gypsy]

So yours are 6 thou short compared to new brass. They are intentionally 3-5 thou short to allow case stretch. So you’re barely over that by 1 thou. Carry on

Why would they need almost the entire SAAMI tolerance for length to shoulder (0.007") less than brass cases which probably stretch MORE?

I'd be surprised if these cases are not below SAAMI min case size spec. They are 10 thou short of my chamber which must be close to SAAMI min headspace.

Edit: looking at SAAMI spec to shoulder, min cartridge to max chamber is a 0.014" difference.. Seems that it might be at or slightly higher than that max difference in Ben's gun.

 

[wind gypsy]

These brass that are once fired and thrown away intentionally allow for case stretch vs being supported? Is that something in the design or sammi spec? I am not in the know, it just seemed counter intuitive as a statement.

Agree that it seems counter intuitive. They seem to be less malleable than brass and cant be reloaded, so why would they have a sloppier fit?

I did send Shell Shock a message inquiring about this.

 

[wind gypsy]

Guys on the Hide reported that the undersized cases seem typical.. I'll try em with 450s or #41 primers to get a little thicker cups. Seems my headspace is likely a hair shorter than Ben's.

 

[Thegman]

So yours are 6 thou short compared to new brass. They are intentionally 3-5 thou short to allow case stretch. So you’re barely over that by 1 thou. Carry on

From what I've seen, NAS3 (Nickel Alloy Shell) cases, don't, and aren't designed to stretch appreciably compared to a brass case. The short base-to-shoulder length is likely creating a larger issue than it would with a brass case which can stretch much more easily.

 

[Str8shtr]

I got a 1-8 twist tikka barrel I could shorten the headspace on if you want to test the cases...

 

[Schmo]

From what I've seen, NAS3 (Nickel Alloy Shell) cases, don't, and aren't designed to stretch appreciably compared to a brass case. The short base-to-shoulder length is likely creating a larger issue than it would with a brass case which can stretch much more easily.

I talked to John over at Blackarc Munitions. He loads these cases for his retail ammunition, as well as working with Shell Tech on the design. He is highly knowledgeable, and what I learned came directly from him. He probably has more experience than anyone with these cases, except for Shell Tech themselves of course

 

[Thegman]

I talked to John over at Blackarc Munitions. He loads these cases for his retail ammunition, as well as working with Shell Tech on the design. He is highly knowledgeable, and what I learned came directly from him. He probably has more experience than anyone with these cases, except for Shell Tech themselves of course

What was his input about them, in general? Anything that applies to the issues @B_Reynolds_AK was seeing? My input is based on the (limited) loading I've done with them.

 

[BBob]

Guys on the Hide reported that the undersized cases seem typical.. I'll try em with 450s or #41 primers to get a little thicker cups. Seems my headspace is likely a hair shorter than Ben's.

Just a wildcard thought and may not work for these. Step neck them. Oversize the neck with a mandrel and partial resize neck length with a bushing die to fit your chamber. You’ve got cases and I’m sure you’ve got the mandrels, bushings and a die. Experiment away

 

[Thegman]

Just a wildcard thought and may not work for these. Step neck them. Oversize the neck with a mandrel and partial resize neck length with a bushing die to fit your chamber. You’ve got cases and I’m sure you’ve got the mandrels, bushings and a die. Experiment away

The one guy I know who tried that had quite the misadventure with these things...

Post in thread 'Ultralight Ultralight Rifles'

Jun 6, 2025

Any of yall running the NAS3 cases? 50% lighter than brass so some weight savings and increased velocity. Seems right up y’all’s alley.

I tore 4 of them in half, ripped my favorite shirt, broke the tip off my needle nose pliers, and sliced my hand open trying to neck them up .5mm with a mandrel for a 6x45.

• Taudisio

• 
• 

 

[wind gypsy]

Just a wildcard thought and may not work for these. Step neck them. Oversize the neck with a mandrel and partial resize neck length with a bushing die to fit your chamber. You’ve got cases and I’m sure you’ve got the mandrels, bushings and a die. Experiment away

Sounds like probably not going to work. And 0.224 is the only caliber i have without bushing dies anyway.

I'll give em a shot as is.

 

[B_Reynolds_AK]

Spoke to Anthony at Shell Shock today. He explained that the cases are supposed to stretch .020" and then contract back in an "accordion" manner. This happens near the base of the case where the horizontal line is.
His take was that the excessive chamber headspace should not be an issue.

He went on to say that millions of cases are being used and often at over 100,000 psi.
His recommendation was to load even HOTTER than I was, to get the case to stretch more and fire form to the chamber fully.

Well.. ok. I dumped 27 and 28 grains (8% more than my max load) of N150 into two cases and loaded with 80 ELD-M's.
Based on my regular loads of 26.0 of N150 with the 80's from my 16" 223, 28.0 would be pushing them in the 3,000 fps range.

I fired both into a snowbank outside my house and this was the result:
Two more pierced primers and a damaged firing pin.

 

[rickyw]

Spoke to Anthony at Shell Shock today. He explained that the cases are supposed to stretch .020" and then contract back in an "accordion" manner. This happens near the base of the case where the horizontal line is.
His take was that the excessive chamber headspace should not be an issue.

He went on to say that millions of cases are being used and often at over 100,000 psi.
His recommendation was to load even HOTTER than I was, to get the case to stretch more and fire form to the chamber fully.

Well.. ok. I dumped 27 and 28 grains (8% more than my max load) of N150 into two cases and loaded with 80 ELD-M's.
Based on my regular loads of 26.0 of N150 with the 80's from my 16" 223, 28.0 would be pushing them in the 3,000 fps range.

I fired both into a snowbank outside my house and this was the result:
Two more pierced primers and a damaged firing pin.

View attachment 1042703
View attachment 1042704

I can’t wait to hear his response when you call him back…

 

[Formidilosus]

Spoke to Anthony at Shell Shock today. He explained that the cases are supposed to stretch .020" and then contract back in an "accordion" manner. This happens near the base of the case where the horizontal line is.
His take was that the excessive chamber headspace should not be an issue.

He went on to say that millions of cases are being used and often at over 100,000 psi.
His recommendation was to load even HOTTER than I was, to get the case to stretch more and fire form to the chamber fully.

Well.. ok. I dumped 27 and 28 grains (8% more than my max load) of N150 into two cases and loaded with 80 ELD-M's.
Based on my regular loads of 26.0 of N150 with the 80's from my 16" 223, 28.0 would be pushing them in the 3,000 fps range.

I fired both into a snowbank outside my house and this was the result:
Two more pierced primers and a damaged firing pin.

View attachment 1042703
View attachment 1042704

Try a different powder. Lever maybe. Haven’t used N150 that I remember, but we did have near identical issues with some VV powder in bolt guns.

 

[Castle Rock]

Spoke to Anthony at Shell Shock today. He explained that the cases are supposed to stretch .020" and then contract back in an "accordion" manner. This happens near the base of the case where the horizontal line is.
His take was that the excessive chamber headspace should not be an issue.

He went on to say that millions of cases are being used and often at over 100,000 psi.
His recommendation was to load even HOTTER than I was, to get the case to stretch more and fire form to the chamber fully.

Well.. ok. I dumped 27 and 28 grains (8% more than my max load) of N150 into two cases and loaded with 80 ELD-M's.
Based on my regular loads of 26.0 of N150 with the 80's from my 16" 223, 28.0 would be pushing them in the 3,000 fps range.

I fired both into a snowbank outside my house and this was the result:
Two more pierced primers and a damaged firing pin.

View attachment 1042703
View attachment 1042704

A couple of things going on here, firstly the Fed 205 is a poor choice of primer for high pressure use being thin and soft.
Also it appears that you are using a standard bolt face bolt, not a small one

 

[B_Reynolds_AK]

A couple of things going on here, firstly the Fed 205 is a poor choice of primer for high pressure use being thin and soft.
Also it appears that you are using a standard bolt face bolt, not a small one

I've read that the Fed 205's are generally ok, but you may be right. I swapped firing pins already with another bolt I had, but only took a pic after I did that, hence the different bolt body.

 

[Castle Rock]

Give CCI 450s a try if you plan to persevere.

 

[Thegman]

Hopefully you get it figured out...(???)

Too bad a firing pin had to die in the process...

 

[B_Reynolds_AK]

Hopefully you get it figured out...(???)

Too bad a firing pin had to die in the process...

I used a buffing wheel on a dremel to smooth it out. Looks ok.