5.56 to .222Rem case conversion

RifleDude

CGN frequent flyer
Rating - 100%
43   0   0
Location
Not in Toronto
Well, I finally decided to retire my old stash of Norma .222Rem cases. After many reloads, the primer pockets were getting a little loose. Being a cheap bast..rd, and having a large supply of Lake City 5.56 cases, I decided to try converting some of them to .222Rem. I tried an inital batch of 10 cases just to see how difficult it would be. As it turned out, not difficult at all. It's a little bit more time consuming than full length resizing but being retired, I had plenty of time. After some experimenting, I found the following procedure worked just fine.

Uewl6Jml.jpg


Start with a full length sized 5.56 or .223 case. Next, trim the case to .222 length and deburr the case mouth inside and out. Lubricate the case lightly and resize in the .222 full length sizing die. Do this in 2 or 3 stages while wiping the lube off the case neck between stages. This process prevents wrinkling of the case shoulder. Clean off the lubricant and you're done. Optionally, you can deburr the inside of the flash hole and anneal the case neck (recommended for developing accurate loads). The above image shows the original 5.56 case on the left, the middle case is the shortened 5.56 case to .222 length and the right image shows the final .222 case ready for reloading.

I worked up one of my pet loads with the newly converted Lake City cases and they're just as good as my original Norma cases as seen below. In my Sako, 24gr of Varget, 50gr VMAX bullet and Federal 205M primers is just the ticket. BTW, these are all 5-shot groups.

kHKN1jpl.jpg


Thanks for watching, I hope this helps somebody that is contemplating this conversion but is still wondering if it's worth it.
 
How thick are the Lake City 5.56 case necks necks after conversion to .222 from the case mouth to the neck shoulder junction. Meaning how much thicker is the neck above the shoulder than the mouth of the case neck. The case thickness in your new necks will decrease the chamber neck clearance the closer you get to the case shoulder. You may need to turn your necks for uniformity and neck clearance, will a bullet fit in the fired case neck.

I ran into trouble converting 30-06 cases into 7.65 Belgian Mauser cases and the base of the necks were too thick and had no neck clearance. And this lack of neck clearance can cause pressure spikes.

See NOTE 6 below and also the amount of case taper thickness on the Lake City 5.56 drawing.

JcVlKzc.jpg
 
I was wondering given it is military hrass if the thickness of the brass was a factor. I was using ivi 308 and had to decrease the powder load due to pressure signs. Keep an eye on that with your new brass.
 
Bigedp51, The case neck just above the shoulder measures 0.250" which is within the SAAMI spec (chamber dimension at the neck is 0.254"). The case neck at the mouth measures 0.245". So, yes, the neck is probably slightly thicker at the shoulder but it doesn't prevent easy chambering in my rifle. Fired cases accept a bullet with no resistance. I hope this answers your question.
 
I was wondering given it is military hrass if the thickness of the brass was a factor. I was using ivi 308 and had to decrease the powder load due to pressure signs. Keep an eye on that with your new brass.

You're right, this is the case for 7.62 brass but not for 5.56 brass. The weight of 5.56 brass is similar to commercial brass. The main difference for military 5.56 cases is harder brass and a thicker web than commercial brass. That's why I like it better than commercial brass.
 
You're right, this is the case for 7.62 brass but not for 5.56 brass. The weight of 5.56 brass is similar to commercial brass. The main difference for military 5.56 cases is harder brass and a thicker web than commercial brass. That's why I like it better than commercial brass.

Ahh good to know. Thank you for the information
 
Back
Top Bottom