I have a 6.8 SPC barrel for my Encore and want to do some playing with it. I have some Rem brass with large rifle primer pockets and some Hornady and Fed cases with the small rifle primers. Just curious what experience others have had with the sm and lg primers in this cartridge. I'm thinking the lg rifle primers in the Rem cases would be better in cold weather if one of the grandkids uses it in deer season. While to sm rifle primers may be fine for targets in warmer weather. Curious how much difference there is in powder charges between the two. Thanks for any info you can share

Nobody playing with this calibre ??

I run all LR Rem brass and WLR primers. Shooting Ball powders mostly and hot or cold they always light. My 6.8 is a Rock River Coyote and it will shoot several bullets sub MOA. I think you'd be best to look at your brass availability and settle on one size primer. Accuracy will be same same unless you are trying to compete past 300 yards and I don't think you will have a noticeable difference in ignition until you reach that 10 below zero mark.

I have a Contender barrel, and have built a few ARs on it.
I have only small pocket brass.
It works well. For such a small powder charge, you don't need LR primers. After all, larger charges of powder use small primers, effectively.
Not something to fret over.

I use pre Nosler SSA brass with CCI 41 primers for use in ARs. As stated above, this is a small capacity case, I can't imagine ignition problems, especially with a magnum primer.

You might take a look at Accurate 2200 powder, this has worked very well for me in the 6.8, also the Barnes 95 grain TTSX.