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.