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Custom sizing dies?

Mike D Texas

Well-Known Member
Joined
Sep 7, 2013
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3,762
Location
North Texas
I am finishing up a 338 Norma Improved build and will need to be ordering a sizing die. I own a few Whidden custom sizers but I've seen more than one comment about them not fully sizing the base and folks experiencing clickers. I'm having some clicker issues with my 6.5SAUM Improved but whether or not that's caused by the Whidden die is undetermined.

Anyway, I am building this on a 35° shoulder similar to my 300 NMI. The 300 NMI is chambered using the AW reamer and I'm using the Micron die from Bullet Central. If there is a 338 NMI version that's what I will get but am open to others as well.

What custom die manufacturer do you recommend? I do not have a die reamer so it will have to be built using fired brass to get dimensions.
 
Popping extraction is not caused by dies, but by a loose chamber for new brass, and poor breech support.
I like JLC Precision. I send them 3 fire formed unsized cases, and they make whatever sizing/sizing die I want from that.
Clickers can certainly be caused by dies that don't size enough at the cartridge base. This is a pretty well known issue and the most common example of this currently is with the 6.5 and 300 PRC.
 
There is a difference between a cause and cure.
Best always to address the root cause.
Your cure in this case (oversizing), by the time you stumble into your issue (due to bad planning and build), is not a good cure.

-As it relates for the OP, the best die is fitted to fully formed cases.
-The best plan & build leads to fully formed cases that barely changed from NEW.
-Barely changing from new, means rational/minimal chamber clearance (reamer setup from new case dimensions), and enough barrel steel around the chamber for intended pressures with given area cartridges. Can also add a coned breech for more support.
If you follow this plan, you will not be surprised with popping extraction.

I don't see the people who supposedly know so much planning for this..
Instead, they seem completely reactive.. And you might notice that their default cures just happen to be even more of the causes.
They're not learning.
 
There is a difference between a cause and cure.
Best always to address the root cause.
Your cure in this case (oversizing), by the time you stumble into your issue (due to bad planning and build), is not a good cure.

-As it relates for the OP, the best die is fitted to fully formed cases.
-The best plan & build leads to fully formed cases that barely changed from NEW.
-Barely changing from new, means rational/minimal chamber clearance (reamer setup from new case dimensions), and enough barrel steel around the chamber for intended pressures with given area cartridges. Can also add a coned breech for more support.
If you follow this plan, you will not be surprised with popping extraction.

I don't see the people who supposedly know so much planning for this..
Instead, they seem completely reactive.. And you might notice that their default cures just happen to be even more of the causes.
They're not learning.
Under sizing brass causes clickers. Minimal sizing as you claim causes clickers. Tight chambers and dies that don't size enough cause extraction issues. It's a pretty well known fact. Your thought process and "plan" would lead to clickers within 4-6 firings. The brass has to grow enough for the dies to actually size it. If it's not sizing the brass just work hardens to the point it causes difficulty extracting. Neck sizing causes the exact same problems as a full length die that doesn't work and doesn't actually size enough. As I previously mentioned, look at Hornady's 6.5 and 300 PRC SAAMI reamer dimensions, then look at the brass dimensions. Do a quick search on here or pretty much any other forum and you'll see that the tight/minimum chamber specs compared to the brass causes clickers and extraction problems. The fix for it, chamber the barrel from the start with a reamer .002 bigger at the base, or open the existing chamber up with the larger base diameter reamer. This is a pretty common issue that tight minimum reamer dimensions and minimal sizing causes.
 
Under sizing brass causes clickers. Minimal sizing as you claim causes clickers. Tight chambers and dies that don't size enough cause extraction issues. It's a pretty well known fact. Your thought process and "plan" would lead to clickers within 4-6 firings.
Well I guess I'm onto something that your entire world doesn't understand.
Undersizing, or even no sizing, does not CAUSE popping extraction, Everything you're talking about are band aid cures for something already caused.

I don't FL size ANY of my cartridges.
I have 50+ reloads on my 6BR, around 60 reloads on my 223Rem, 80+ reloads on my 26WSSM, I burned out a 6XC barrel with the same 20 cases.
Never an extraction issue. No loosening pockets, no extra trimming or re-turning or re-annealing. I don't EVER have to replace cases.
 
Well I guess I'm onto something that your entire world doesn't understand.
Undersizing, or even no sizing, does not CAUSE popping extraction, Everything you're talking about are band aid cures for something already caused.

I don't FL size ANY of my cartridges.
I have 50+ reloads on my 6BR, around 60 reloads on my 223Rem, 80+ reloads on my 26WSSM, I burned out a 6XC barrel with the same 20 cases.
Never an extraction issue. No loosening pockets, no extra trimming or re-turning or re-annealing. I don't EVER have to replace cases.
So I guess everyone else is wrong but you? Funny how that works.
 
I am finishing up a 338 Norma Improved build and will need to be ordering a sizing die. I own a few Whidden custom sizers but I've seen more than one comment about them not fully sizing the base and folks experiencing clickers. I'm having some clicker issues with my 6.5SAUM Improved but whether or not that's caused by the Whidden die is undetermined.

Anyway, I am building this on a 35° shoulder similar to my 300 NMI. The 300 NMI is chambered using the AW reamer and I'm using the Micron die from Bullet Central. If there is a 338 NMI version that's what I will get but am open to others as well.

What custom die manufacturer do you recommend? I do not have a die reamer so it will have to be built using fired brass to get dimensions.
If your 338 NMI is based off the same body and shoulder specs as the AW2 300NMI reamer, you could probably use a Micron die. It may have to be opened up slightly at the shoulder-neck/bushing junction for the larger diameter neck to pass through. It would be worth measuring your current 300 NMI die at that point to see what the diameter is.
 
If your 338 NMI is based off the same body and shoulder specs as the AW2 300NMI reamer, you could probably use a Micron die. It may have to be opened up slightly at the shoulder-neck/bushing junction for the larger diameter neck to pass through. It would be worth measuring your current 300 NMI die at that point to see what the diameter is.
This is exactly what I'm doing on a build I have in progress. I'm using my 300 Norma Imp reamer and then a 338 neck and throat reamer to finish the chamber. I will then use the Bullet Central Micron die and open it up for the 338 neck to go through it into the proper 338 bushing.

If your reamer is a 338 Norma reamer that was improved to a different angle shoulder the 300 Norma die probably won't work. The 338 Norma is .008 bigger at the neck/body junction.
 
If your 338 NMI is based off the same body and shoulder specs as the AW2 300NMI reamer, you could probably use a Micron die. It may have to be opened up slightly at the shoulder-neck/bushing junction for the larger diameter neck to pass through. It would be worth measuring your current 300 NMI die at that point to see what the diameter is.
I considered that but I believe the dimensions on the 338 are slightly larger in more than neck diameter on the 338 vs the 300. I would need to do a drawing overlay to confirm.
 

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