6.5 CM small rifle primer reload data?

[Chilly807]

I'm looking at reloading for 6.5 Creedmoor, all the reload data I've found specs a large rifle primer. If I choose to use Lapua brass, which I prefer to do, it uses a small rifle primer. How much difference if any does that substitution make to a starting load?
I suspect anyone using SRPs instead of LRPs in Lapua 308 Palma brass has had the same question.

 

[Ganderite]

Primer (L vs S) makes no difference. The variation of load data from rifle to rifle is huge compared to a difference in a primer.

If you have used Large primers in that rifle before, use the same data for the small, but test plus or minus .3 gr because it is a new lot of brass.

 

[Chilly807]

It's a new rifle so I'll be starting from scratch. I was expecting the smaller size primer to be a bit weaker, but I'll begin with starting loads and work up in any case.

 

[spoc]

I have brass with both the large and small primer and I haven't seen any difference between the two.

 

[kewp]

I have used both in my 6.5 . I ended up loading the lapua smalls at .1 less than the other brands large rifle in order to match velocity in my rifle . Not because of primer size but because of case volume . Did notice an improvement in spread and deviation using the lapuas but that could have just been a good day or newer , better brass .

 

[Chilly807]

To revisit and give some closure to the thread: I started with a book minimum charge of H4350 and CCI BR-4 primers under 123 gr SMK's, then worked my way up using Sierra's suggested increments til I got to 2800 fps. The data in the Sierra manual (online addition for the 6.5 Creedmoor) is for a large rifle primer.
The results I got using the small rifle primers in Lapua brass mirrored listed velocities almost exactly, just as the folks who replied to my question suggested they would.
I have to say, I think Lapua is on to something by using the SRP and small flash hole in their "target" caliber brass. I've never had more consistent results with ES and SD numbers.
Thanks again guys, your experience was a great help!

 

[Icefire]

Lapua isn't the only one using SRP, I bought 150 new Peterson brass and they look top notch.

I would suggest you look into 143-147gr range if you do long range, 123gr might be good but I would guess those high BC would help better in the wind.