headstamp?

[J E Custom]

Belted cases will head space correctly most of the time, but the cartridge will/can change drastically when fired. Some will fit in the chamber with the wrong size bullet
and this could be dangerous, so it is always best to have the proper head stamped cases. You are right to worry about someone else using it in the wrong application
because it does happen.

Fortunately some wildcats like the AIs wont chamber in the parent cases that are stamped with the parent cartridge head stamp because they are bigger, But many wildcats are formed without increasing the case dimension and only increasing the bullet size (Caliber) Like the 300 Blackout and when it is chambered it pushes the bullet back in the case and re sizes the neck. It will still fire !!!.

In my opinion the cost of the brass is not worth the risk or worry if it can be avoided.
I have seen many cases where the wrong cartridges have been fired in the weapon that matches the chamber ID on the barrel with dangerous to bazaar results and it is scary.

J E CUSTOM

 

[cohunt]

Correct me if I do not recall correctly, but From my reading, a +0 NATO headstamp is, by default, 5.56

nope-- the O+ just means NATO-- 9mm and 308 have it also

 

[eschafer]

Belted cases will head space correctly most of the time, but the cartridge will/can change drastically when fired. Some will fit in the chamber with the wrong size bullet
and this could be dangerous, so it is always best to have the proper head stamped cases. You are right to worry about someone else using it in the wrong application
because it does happen.

Fortunately some wildcats like the AIs wont chamber in the parent cases that are stamped with the parent cartridge head stamp because they are bigger, But many wildcats are formed without increasing the case dimension and only increasing the bullet size (Caliber) Like the 300 Blackout and when it is chambered it pushes the bullet back in the case and re sizes the neck. It will still fire !!!.

In my opinion the cost of the brass is not worth the risk or worry if it can be avoided.
I have seen many cases where the wrong cartridges have been fired in the weapon that matches the chamber ID on the barrel with dangerous to bazaar results and it is scary.

J E CUSTOM

Thank you.... your post above has just solidified my decision.... I'm nearly 60 years old, not new to life but new to rifles, ammo, reloading and hunting.... Your reply is very sensible...

 

[Varmint Hunter]

I can't imagine how a 338 Win mag cartridge could fit into a 300 Win mag chamber. The loaded 338 ammo neck wouldn't enter the chamber neck.

In the 300B vs .223 example, I assume this is possible because the 300B is so much shorter than a .223 and the case neck never reaches the chamber neck.

 

[eschafer]

Moderator.... Please close this thread......

 

[freddiej]

I have both the 300 W/M and the 338 W/M, I took a dummy 338 and tried to close the bolt on it in my 300.. no go, the slug stops the bolt from closing.
now if you do the same thing with a 300 RUM and a 338 W/M it will close. bad things happen but the bolt will close.

 

[J E Custom]

I can't imagine how a 338 Win mag cartridge could fit into a 300 Win mag chamber. The loaded 338 ammo neck wouldn't enter the chamber neck.

In the 300B vs .223 example, I assume this is possible because the 300B is so much shorter than a .223 and the case neck never reaches the chamber neck.

In both cases, the bullet hits the neck part of the chamber first and is forced backwards into the case ans the neck is then sized down by the neck chamber. this takes less effort than you would think, especially when you have Adrenalin working for you if you are excited or making a follow up shot.

Someone posted a picture of the 300 blackout fired in a 223. the bullet was stuck and about 3'' long in the .223 bore.

J E CUSTOM

 

[Edd]

My question: is it possible for a .338 wm cartridge (typically seated bullet) to chamber/battery into a 300 wm rifle? Reason I'm asking, just a little concerned about safety, should I ever go this route.... I don't have said 300 rifle here to try a dummy round in... Thanks in advance...

A 300 Winchester chamber has a diameter of .342 inches at a length of 2.362 inches.

A 338 Winchester case has a diameter of .369 inches at a length of 2.480 inches.

So, the minimum you would have to do is apply enough force to push the neck back .118 inches. That would not be easy to do. When the dimensions of the bullet is entered into the calculation, the amount of force required will increase.

If you are wanting some brass that you can size to fit your chamber, you might consider 308 Norma Magnum brass.

 

[Black Hat]

It will not chamber, especially once fire formed, as the .338wm has a 0.020" larger shoulder than the .300wm

 

[Edd]

It will not chamber, especially once fire formed, as the .338wm has a 0.020" larger shoulder than the .300wm

On the spec sheets I have, there is only about .0001" difference.

 

[Philip J Theodhor]

Just for comparison both the .300 WM & the .338 WM share an identical shoulder angle of 25 degrees, however from this point on the cartridges are not compatible without reworking your brass via step up dies and trimming to length although the head diameter and web thickness and the belted case diameters are the same.
Here in lie the issues.
.300 WM angle .339" -. 490" diameter X .464" in length
.338 WM angle .369" - .491" diameter X .331" in length

.300 WM C.O.A.L = 2.620"
.338 WM C.O.A.L = 2.500"

.300 WM Neck Diameter of brass (O.D.) = .339"
.338 WM Neck Diameter of brass (O.D.) = .369"


Now even after you get to the correct reworked brass numbers from .300 WM to .338 WM you still must anneal your brass, open up your neck ID,then form your necks OD.
and you still wont know if it will chamber correctly. Remember tolerance stacking issues will come in to play here as well.
IMHO this is just another exercise in futility !

 

[Oldschool280]

Just to be sure, you can always write on each case with a sharpie, cartridge, bullet , powder type and charge.