Discussion in 'Reloading Forum (All Calibers)' started by rebs, Jun 28, 2019.
Is there any advantage using magnum primers when reloading 223's with Varget or Reloader 15 ?
Thicker cups, less chance of piercing.
It depends, are you reloading for an AR? SRM primers usually have a thicker cup and resist piercing and slam fires from the floating firing pin.
After that, test and let your rifle tell you which it likes.
Lake City uses magnum primers with all their 5.56 ammunition.
CHOOSING THE RIGHT PRIMER - A PRIMER ON PRIMERS
Primer Info & Chart + Milspec Primers for Semi-Autos & Other Primer Applications
Small Rifle Standard
CCI 400 -thin .020" cup, not recommended for AR15 use by CCI/Speer. Good for .22 Hornet, .30 Carbine. See Note 1 at the bottom of the page
Primers recommended for use in .223 Rem/5.56 semiautomatic rifle loads:
CCI #41, 450, BR4
Federal 205, 205M
Remington 7 1/2 BR
NOTE 1: According to Speer/CCI Technical Services - Both the CCI 550 Small Pistol Magnum and CCI 400 Small Rifle primers are identical in size. Both primers use the same cup metal and share the same cup thickness. Both primers use the same primer compound formula and same amount of primer compound. They can be used interchangeably.
I am asking about using them in a bolt gun
Remington 7 1/2s are sometimes listed as magnums, I use them almost exclusively in my bolt guns.
There's some data in I think in the Speer manual on using magnum primers in .223.... They are mainly used with ball powders that are harder to light off than stick powders.... As per normal you will want to back the charge off and work up with them... I don't see any reason to use them with stick powder unless you just want to... The thicker cups can prevent slam fires in automatics but I just use normal CCI S/R primers in my AR loads and have never had the problem , fortunately mine don't seem to hit the primers , my SKSs are a different story , it hits them scary bad.... You using a bolt gun will not have these problems....
So Ed if I am reading the chart correctly they are using no 41 primers..? If so then the 41s are a magnum primer..? I have always thought the no 41s were just the 450 primers repackaged...
CCI makes a special primer for Ar's which have a harder surface. This is to prevent slam fires. If you are loading for a bolt gun, then regular primers will be the best bet. Magnum primers are hotter but there is no reason to suspect that they are a danger.
The CCI #41 and CCI #34 are both magnum type primers One large difference between, for example a CCI #41 small rifle primer and a CCI 450 small rifle magnum primer is the CCI #41 also has the anvil at a slightly different angle in addition to the slightly thicker cup.
Regarding CCI #34 primers. The question has come up or it has been stated that CCI #34 primers are the same thing as CCI 250 Large Rifle Magnum primers. While I know the CCI #34 is a magnum primer I believe it is not the same as other large rifle magnum primers in that it has further reduced sensitivity. Would that be correct and is the priming mix different than standard large rifle magnum primers.
Ron, here are the differences in the 2 primers. So the anvil angle change is the difference, this keeps the free floating firing pins from causing slam-fires in AR style platforms. This does make it so that a light strike will have a less of a change of going off.
CCI-250............................ Magnum primer, Mag primer mix, thick cup, standard anvil.
#34/7.62MM................... Mil. Spec. primer, thick cup, magnum primer charge, angle of anvil change.
Justin M./Technical Service Rep.
2299 Snake River Ave.
Lewiston, ID 83501
The replay mentions the #34 LR but also holds true for the #41 SR. CCI is always happy to address any questions you toss at them.
Good info , thank you Ron
The #41 primers have a thicker cup and a shorter anvil that requires more force to set the primer off.
That being said when Remington ran Lake City they used their 7 1/2 primers in the 5.56 ammunition for over 25 years.
With the AR15 the greatest chance of a slam fire is when a single round is loaded without the magazine in place. When the round is fed from the magazine it slows down bolt velocity and firing pin inertia. Both the M14 and M16 rifles had their firing pins lightened during their trial period to help prevent slam fires.
Bottom line read the entire link I posted and the recommended semi-auto primers which all have a cup thickness of .025.
Remington 7.5 for most all high intensity cartridges. Same 7.5 in a AR load or the CCI #41, which is made for use in semi-auto's.
Bolt Gun Answer!
450 in my SP Peterson .308 F/TR Rifle
Also in my 6 Norma Dasher . Give lowest SD.
Tried Wolf SRM in above Rifles , got failure to fire every so often.
Always used CCI 250 in my Match M1 A
very good article, thanks for posting it
I have been testing the CCI 450 and the CCI BR4 against each other for a couple of years. In the .223 with Varget I can see no difference. One day the 450 wins and the next the BR4 wins. I started using the Mag primer in the .223 back when you couldn't get primers. What I found was there was an immediate improvement in my groups. Who knew? Now I try and keep a 4 year supply of primers just in case.
A few years ago I did a little science experiment using all CCI primers in a 223 Remington bolt gun I put together. Each of the four groups were shot at 100 yards and they are 10 shot groups. I was more concerned with getting the groups over the chronograph than holding and squeezing for group size. The brass was all LC 11.
Here are the velocities I ended up with and each powder charge was hand weighed, all the cases were the same sized and trimmed the same. I wanted as much uniformity as I could get in the loads. The best standard deviation was the BR 4 primers but the CCI #41 gave the best group but again I wasn't really focused on group size as much as not shooting my skyscreens.
Finally the target.
.223, varget, and 450s go together like peas and carrots for 75g and above.
It's kind of hard to beat a CCI 450 for any cartridge it fits into...
Separate names with a comma.