Going to work up some loads for 6.5 CM soon. Have bullets brass and picked up some H4350 but finding some primers seems to be issue! What primers are working the best, I have plenty of CCI large rifle but which ones give the best performance?

CCI #200 primers will work perfect for your application. I use Fed 210 or 210M primers for 6.5 CM. The #200 will work fine, though.

Used more CCI 200 that I can remember. I've not noticed one thing or another in them versus a Fed 210. I can say, I have seen great ES numbers with CCI BR-2, but dang ya gotta pay fer em!

Thank you gents! I see most velocities are being measured out of 24" barrels. I am shooting a 20" braked AR barrel so going to be some wasted burn, should there be adjustment in charge weight? Going to start around 43.5 of H4350 and work on group verses velocity and watch for presure signs.

No clue which bullet, so I need to know that first. If you are shooting a 140 grain weight bullet, 43.5 is a very warm load, if not over max. Yes, you will not have as a complete burn in an AR as in a bolt gun. But you can not make up that burn by adding more powder. It will still be a higher pressure round.

^^^^ This

I've tried and test frequently but it either comes down to the Fed Match or the br2 with the br2 beating out the Fed more often than not. Which is backwards from most of the small rifle primers I use. The mag or Fed match almost always beat the br4...weird and makes no sense to me????

140 ELD's is what I have but may pick up some 120's down the road, I hate when some people think more to make up for waste is the answer. If I think there is waste in burn I would rater find the most efficeant. I prefer mild/moderate chamber pressure with acceptable accuracy.

Well in a 20" barrel, I'm showing 2660 fps with Varget with 100% burn rate. With H4350, I'm showing 43.5 grains as max charge at 2682 fps with 98% burn rate. Now this is all calculated in QuickLoad for a bolt gun, and gets you in the ball park. Shooting these in an AR will not be as efficient, but close to it. I know from experience that 43.5 grain of H4350 is certainly a max load, if not over max and over pressure in most 6.5 CM rifles. So, this 43.5 grains should be not be something to start with and I would not go that hot. To make the rond more efficient, you would need to drop down to s faster burning powder, like Varget. But, you may give up a little speed, maybe not. With an AR, just don't go too hot with it. If you have an adjustable gas block, close the port up some so less gas is coming back to the action for lower pressure.

Start at 41.5 or 42 and go from there. 43.5 is real hot. I was worried about my load at 43.2 and I occasionally see pressure signs, and that's with a long-throated Tikka that increases my volume and artificially reduces pressure below a more normal chamber/throat.

If you're looking for premium accuracy with the 140 and 4350, most folks find their node between 42 and 43.

Absolutely! In a bolt action.

I'd listen to Chad and increase the burn rate in an AR. I helped a customer find a load in an AR chambered in 6.5 Creedmoor, and we used H-Varget after Chad spent 30 minutes playing with various burn rates in Quick Load.

Great info!Will give me safe numbers to work up from! I saw a thread on snipershide where Hornady use to have load data on the box and it was showing bullet,primer,powder and coal. Think they stopped doing that out of liabilty.

I have a really solid load that is mild with the 120/123 gr bullets using AR Comp but have not tried it with 140’s
The best AR load I worked up with 140gr was with IMR4007 SSC but kinda hard to find these days.... discontinued.
Something in the Varget burn range should do the trick as mentioned above.

Fair point. You gas gunners have more to think about than us simple folks. My gas gun is a Ruger 5.56 with iron sights.

Yes, they originally used 41.9 grains of H4350, then later reduced it to 41.5 grains. Then they stopped putting it on the box. I had pulled some factory ammo, and it certainly was not 4350 any longer. It was a ball powder now.

43.5 grains is certainly a pretty warm load I would not start with if using 140 grain bullets just as a precaution. I would start low and work up, especially in the hot dog days of summer. I use 42.4 grains of H4350 and 140 Berger Hybrids out of a bolt gun.