Primers: Std. vs. Magnum

[L.Sherm]

If I remember correctly Remington recommends only using the 6.5 in hornet style cases.

 

[milo-2]

I got my 6.5x47 in early 2016 and it was a 9 month wait for the rifle so I read all the stuff I possibly could on line about reloading for it. A guy from TBAC had done a lot of testing and recommended the CCI 450, so I bought 1,000 of them and I'm down to about 500. Im sure the 205s are good too but I was just totally infatuated with the "magnum" status of my new primers! What a Mall Ninja, huh?

Mall Ninja, good stuff! If what you have works. stay the coarse.
I did a CCI 450-205M test on Dasher cases, I was loading for 4 of them, 3-1 in favor of 450. One 450 - Varget load lost some zest, tested both, numbers way better with 450, groups better with 205M, tough choice. I have a 6 BRA barrel done, I may dedicate a 205 mated with Varget and roll the dice.

 

[Jakeweb09]

I use the 450s in a creedmoor and they are excellent

 

[Scott E Ames]

FYI From the mistakes that turned out well column. I grabbed a box of 205 match primers instead of my usual CCI 450's for my RL 23 6.5 CM loads with 140 bergers. I didn't find the error until 15 rounds were loaded so out of laziness I thought I would try them and hope for no problems. I found that I got an extra 35 fps and SD of 4 and ES of 9 and my 200 yards groups were 0.24 MOA. (all improvements over the 450's) I have also read about ball and slower powders needing a magnum primer in the small primer Creedmoor case but in some situations this isn't the case. If it was below zero in December there might be different outcome???

 

[milo-2]

FYI From the mistakes that turned out well column. I grabbed a box of 205 match primers instead of my usual CCI 450's for my RL 23 6.5 CM loads with 140 bergers. I didn't find the error until 15 rounds were loaded so out of laziness I thought I would try them and hope for no problems. I found that I got an extra 35 fps and SD of 4 and ES of 9 and my 200 yards groups were 0.24 MOA. (all improvements over the 450's) I have also read about ball and slower powders needing a magnum primer in the small primer Creedmoor case but in some situations this isn't the case. If it was below zero in December there might be different outcome???

If it is below zero I will be inside doing things, so no clue there.
Yours is a classic example of getting a more consistent burn w/o the magnum primer. 2 big factors when discussing small rifle primers in the creed case, large or small flashole. I can see the non magnum doing better in small flasholes. I tried CCI 450's in a 6 creed, Lapua brass, with Norma MRP, erratic numbers and the majority were hangfires.

 

[Mikecr]

I want the least powerful primer that tests best with my powder/capacity. With this, I also begin with thinnest cup standard primers, because I also want the least striking force that reliably fires primers.
But ultimately, only TESTING leads to best primer for your system.

 

[L.Sherm]

Out of the big 3 ( federal, Rem and CCI ) CCI is the only one that claims "magnum"

 

[243winxb]

In SR primers there is no difference other than cup thickness.

Old cci chart

 

[243winxb]

Call the manufacturers and ask the question see what they say.

Great idea.
Or work up loads with both 400 & 450. See what primer flows into the firing pin channel first.

Federal primers are the only ones that may contain Nitroglycerin.

 

[L.Sherm]

View attachment 201487


Old cci chart

All I can tell you is between 400 and 450 I've never seen a difference far as velocity when using both over the chrono.
I prefer 450's and 7.5's

 

[L.Sherm]

I was doing load development in a 20 Blitz (20PPCAI) a couple weeks ago and was testing some 450's and 7.5 and the exact same same charge and powder the 7.5 as 20 fps faster.

 

[gilk1]

A lot of people say the magnum primers give more consistent velocity but I havent noticed a difference in 223 but I know the 450's have a thicker cup and re recommended for ar15's.

I haven't had a problem with 400's in my ar's but I had to switch to 450's in my 223 bolt gun after I pierced and 400 and broke the sear in my trigger.

 

[TRG65]

I reloaded the 6.5x47 for over a decade as my primary match round and I've used CCI 41 in almost all the reloads. I tried the CCI br, (I still have most of the 1k box I got) to see if there was an improvement and it wasn't noticeable, so I went back to cci 41. I've always been able to get SDs in the single digits, and when the SD's creep over 10, it's a sign the barrel's about done. I've run SRP brass in 4 6.5x47s and 1 6.5 Creedmoor. The Rem 700 actions or rem 700 clone (Bergara) had to be sent to Gre-Tan for the firing pin to be bushed. The Sako and the Ruger that I've used did not need bushed for SRPs.

 

[lotech]

With regard to .223 loads for ARs, I've found generally, not always, that I get best accuracy with CCI-400s, followed by CCI-450s, and then Remington 7 1/2. The differences are small but enough to notice. However, I normally use the CCI-450s because of the thicker cup, but any of these primers work fine. Best to test them in your gun to be sure.

I'd have to look up chronograph figures, but I don't recall much difference in muzzle velocities with any of the primers.