223 small rifle primers or magnum primers?

[Laurie]

IIRC, the .222 (direct parent of the .223) is the very reason for the existence of small rifle magnum primers in the first place, since they ended up piercing the thinner/softer regular small rifle primers a ton back when the cartridge was first being developed.

Correct. Although with lower pressures than the later 223 and 222 Rem Mag, a harder-cup primer seems barely necessary. So Remington developed the 7 1/2 for the new cartridge sometime around 1950. Although designated a 'magnum', the original version had the same explosive pellet as the standard # 6 1/2. (Other manufacturers have done this too in some cases as @markm87 says in post #5.)

When Remington later developed its .17 Rem cartridge, the 7 1/2 was uprated to be chemically 'hotter' too to provide satisfactory ignition in all conditions.

I did an SRP test in SR 308 Win Lapua 308 'Palma' brass some years ago, and found no correlation between MV levels and primer type as opposed to make/model. As MVs are related to chamber pressures presumably the latter too. This was unlike the results from a previous 308 Win based test series using LR brass and primers.

https://www.targetshooter.co.uk/?p=2662

 

[boltfluter]

The Rem 61/2 was designed to be used in much lower pressure rounds like the .22 Hornet and such. Mild rounds in .223 would probably be fine as well. With the emphasis on "mild loads". Just an fyi, certain powders work well with certain primers. As in, CCI-450 and Varget are a great match, as is H335 and a Rem 7 1/2 primer. VV133 and a Fed 205m is another great one. Just something to consider. I am sure there are many other great combinations as well.
Paul

 

[Timon]

I have run 400’s in my 223 bolt gun, along with N133 powder, for many years without any issues. I do not run hot loads though, but they are on the upper level of the recommended loads. I wanted to see if the 450’s would do anything for me. I loaded 50 of them, 10 groups of 5 each. The groups with the 450’s we just awful, they opened up terribly. I went back to the 400’s.

 

[ELR LVR]

I’m pretty sure that if you look at the warning on the back of the box of Remington 6 1/2 primers, it will have the same type of warning that the 1 1/2 pistol primers have. Indicating low pressure cartridges only and listing multiple

222 and 223 based cartridges should be avoided.

Been a while since I bought any.

Thats good advice
I know a guy COULD, load them down to be able to use the non mag primers
if he wanted
But if anybody is like me
I pump my 223 up to the max sometimes
Even got 3500 fps with 50's in a 22" barrel with no issues
So
Even in the low pressure 223, People should be mindful of exactly what they're trying to accomplish and use some common sense
Instead of
"these are small rifle??? What's going on???" I dont get it???

 

[whatsupdoc]

I have put over 4 thousand CCI400 primers in a rem 700 with the firing pin bushed
with not a single issue using full power loads.

I would never use them in a gas gun. The thinner wall cups dont have the same grip
on the sides of the primer pocket, and AR's are notorious for popping primers. They
crimp military ammo primer pockets for a reason.

 

[jwv2001]

What’s the benefit of using small rifle magnum primers especially in long range shooting in my 223’s or 22-250.

22-250 uses large rifle primers

 

[ern.santos]

...
I did an SRP test in SR 308 Win Lapua 308 'Palma' brass some years ago, and found no correlation between MV levels and primer type as opposed to make/model. As MVs are related to chamber pressures presumably the latter too. This was unlike the results from a previous 308 Win based test series using LR brass and primers.

https://www.targetshooter.co.uk/?p=2662

I remember Dennis Flaharty making a similar comment back in...2010(?) in the pits at Sacramento during a club 3x600 match.