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Old 09-19-2020, 12:21 AM
mefizto mefizto is offline
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Default Two different neck sizes on .222?

Greetings all,

you might have noticed my obsession trying to figure out the cases and chambers dimensions. ;-)

As part of the obsession, I have measured several .222 cases that I have been hording, because one of those days, someone offers a rifle built on an action that accept two-stage trigger, and I will obtain it.

The cases fall into two distinct categories, one with neck size 0.254 inch and the other with neck size 0.246 inches. I have consulted SAAMI. but the only reference is for 0.254 inches neck size.

Any input?

Kindest regards,

M
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  #2  
Old 09-19-2020, 05:53 AM
Daryl Daryl is offline
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As I understand this, there may be rifles and thus brass made up specifically for "tight" necks and "fitted" necks. Same might go for .22 and 6mm PPC.
Tight necked chambers leave only about .0015" for expansion, while fitted neck chambers, are the same size as the brass or perhaps .0005" larger, thus loads must be worked up from low pressure. Upon firing the brass releases the bullet, just barely, then springs back about .001" to a tight fit on a bullet, so no sizing is required. De-prime, re-prime and dump in the powder and seat the new bullet.
That .246" neck size sounds familiar to the .22PPC. I think my PPC Wilson dies came with that size button.
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Old 09-19-2020, 02:19 PM
Nor Cal Mikie Nor Cal Mikie is offline
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So as I see it, you'll have to settle on one brand of brass and STICK with it.
And things will change after it's fired and resized a few times.
Had issues with Remington .221 Fireball brass, new and fired, converted into VT. Necks were all over the place. Finally settled on a .234 neck and I didn't have to neck turn.
What you'll have to do is stock a supply of brass for your project, settle on a neck size and be prepared to neck turn as needed.
Big difference between 0.246 and 0.254. Reamer neck specs as necessary.
I finally settled on the .234 VT neck so I didn't have to neck turn. No more issues.
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Old 09-19-2020, 03:53 PM
JohnHenry JohnHenry is offline
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The .246 neck chamber was a popular spec for short range benchrest when the 222 "ruled the roost" prior to the 6PPC. Neck turning was required. You will also find that Remington went to a .250 neck chamber on their 40XBR to give one a tight neck chamber w/o neck turning for the brass available at the time. Current unturned Lapua brass will have an OD with a seated bullet of .250 +or- a few .0001".
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Last edited by JohnHenry; 09-19-2020 at 03:58 PM.
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  #5  
Old 09-19-2020, 04:26 PM
charlesasmith charlesasmith is offline
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Default Neck thickness

+1 on Nor Cal Mikie's recommendation. If you have .254 necks, you will probably have to turn them to sllow some clearance for a .254 neck chamber. If you wind up with a barrel having a .250 neck chamber, the .246 neck brass will work.

Buying a used gun without knowing the neck diameter is always a crap shoot for determining the proper brass neck size. That is why many reloaders order new barrels and have the chamber cut to their specs to fit their specific brass.

Also, getting a two stage trigger on an older .222 Rem will probably be very difficult. You may consider getting a replacement trigger.

It is one of my favorite cartridges for small critter varmint shooting.

Chuck
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  #6  
Old 09-19-2020, 05:37 PM
mefizto mefizto is offline
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Greetings all,

thank you for your replies. I have been inquiring for two reasons. First, as I understand, the SAAMI specification assure that (production?) rifles and corresponding ammunition are compatible. Second, on a different thread I questioned whether there is a difference between the chamber neck dimension and the case neck dimension that should not be exceeded.

Regarding the first, it appears that the "non-SAAMI" rifles were made by re-chambering by individuals. However, JohnHenry suggests that even a production Remington rifle was "non-SAAMI".

Regarding the second, based on Nor Cal Mikie's post, there is a limit on such a difference. What is it?

Kindest regards,

M
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