Small rifle primers V large rifle primers.

The Vortex nation podcast have been doing some testing with interesting results.

They tested 6.5mm Creedmore with small rifle primers, small magnum primers, large rifle primers and large magnum primers.

https://www.youtube.com/watch?v=lZ15xhtjx-c

https://www.youtube.com/watch?v=3jGEZtuB32o0

They plan to repeat this in winter to see what effect the cold has and also do test a couple more calibres possibly .308

Results were interesting.

Warning this is a Podcast so actual shooting scenes are shown. I find these podcasts quite good and I usually learn something from them.

One thing I discovered early on in the small vs large primer debate is that small primers fall out of large primer pockets very easily.

I've played with palmer brass, magnium primers in 308W, found that they lost about 30ft per second, but the ES was much improved. The primer pockets are more robust & will stand more reloads. Went back to standard brass, as the flash hole is way smaller and a hassle to remove primers, you need a special decapping pin.

I haven't watched the video, but what I found was I could run around a grain more powder with the small primer brass with the 6.5 CM but I had to to get the velocity equal the large rifle brass potential

I've smacked off my fair share of SRPs in 6.5 CM and .308 some srp brass such as Starline has a larger flash hole so look for that if worried about the smaller size with brass like Lapua palma. You can get a small size pin for Lee decapping tools.
Forster dies run a small pin too.
If running Ball powder you want to use a HOT primer such as Rem 71/2 don't use the 61/2 it's thinner. If running 100% charge fills or close to it use a hot primer too.
Look up the charts for cup thickness to see what works.
Generally you will need 0.5 grain increase over LRP charges but as always test for yourself. SDs will be better, case life will be better.
I would have cases that have 20 firings on them (Lapua palma) I anneal every time. I have probably trimmed them three times. According to GRT my loads are up around 60,000 psi.
I have zero loose pockets and have not discarded a case due to separation signs or split necks.
Some of my brass is now on its third barrel if that makes sense (it's been in 3 chambers albeit match chambers)
I also have LRP brass to compare but since small primers are more available I am happy to keep using them.
I haven't shot them in sub zero conditions and only used them in hunting in the NI
Haven't listened to the podcast yet.

In 6.5 CM I had hang fires with standard SRPs (I think it was Fed in the blue boxes but also might have been CCI 400's) changed to CCI 450's and have run hot primers ever since.... no more click bangs.

I've been running Standard Federal SRP's in in my 6.5 creedmoor, 143gn ELDX with Superformance powder. good accuracy and no issues. Using Starline brass because it still has the larger diameter primer hole. I get virtually the same velocity as using LRP's in Hornady brass with the same load.