CCI BR2s in 6.5 SAUM

[jraulsten]

I typically load my 6.5 SAUM with ADG brass, 60.2 grains of H1000, CCI 250 primers and Berger 140 Hybrids. This combination gives me 3050 FPS with an SD of 7-8. Gun specs are:

LPR 6.5 SAUM (tack driver as you would expect from Dallas!)
.081 freebore
GA Hunter action
Bartlein 22" 8 twist
Manners LRH
TT Diamond Flat Shoe @12 ounces
Banish 30 suppressor

I've put 369 rounds through the gun in a month because it is so fun to shoot and to be honest, pulling the trigger to me is as much fun as you can have with your clothes on.....

I finally had the chance to air it out this past week and true velocity/BC in my Kestrel. Everything was spot on with no corrections required. All rounds were right on the 1" water mark at 575 and 775 yards. Elevation was perfect at 900 and 975. I know, I should have left well enough alone but I like to tinker in hopes of making good things even better.

I have a lot of BR2s laying around so thought I would give them a try to see if they might help bring down the SD. Loaded some up and went to the range yesterday with high expectations but initial results were very disappointing. I would have thought velocity would have decreased with BR2s but just the opposite was true. I saw faster speeds, worse SD and slight pressure on some rounds. Thank goodness I loaded several different charge weights. Just about the time I was ready to go home and pull bullets and deprime I decided to shoot my last 5 rounds loaded at 59.3 grains of H1000. Almost a full grain less in powder gave me an average of 3040 FPS! On top of that, SD was 0. Every shot was 3040 or 3041. I know 5 shots isn't a good representation of SD, but I also don't think it was a fluke.

Anyone else seen a velocity increase like that switching from CCI 250s to BR2s?

 

[Mark37082]

Sometimes you find the sweet spot by tinkering. It is very interesting to see that kind of shift going from magnum to standard primers. I guess you won't be needing those 250's any longer……

 

[Longtine88]

In a 7mm Saum I actually have better results with non magnum primers. Better ES/SD's numbers and better accuracy. I've been there and tried it. I even tried it in a 28 nosler and had the same results. So now I really don't pay that much attention to Magnum primers unless I'm shooting a super slow powder maybe then I'll tinker a little with it. But all in all I have never seen a negative result yet with regular primers. Now I will say that I have never used regular primers in extreme cold temps which might make a difference. I'll also say that magnum primers hit higher velocity quicker with same powder charge as regular primers. That being said you probably will have to adjust your charge for sure because of the change in pressure curve.

 

[jraulsten]

In a 7mm Saum I actually have better results with non magnum primers. Better ES/SD's numbers and better accuracy. I've been there and tried it. I even tried it in a 28 nosler and had the same results. So now I really don't pay that much attention to Magnum primers unless I'm shooting a super slow powder maybe then I'll tinker a little with it. But all in all I have never seen a negative result yet with regular primers. Now I will say that I have never used regular primers in extreme cold temps which might make a difference. I'll also say that magnum primers hit higher velocity quicker with same powder charge as regular primers. That being said you probably will have to adjust your charge for sure because of the change in pressure curve.

I only used BR2s in my 7 SAUM and 7 SS so never realized what a difference it could make going from 250s to the BR2s.......Especially the increased velocity with BR2s in my particular gun.

 

[Longtine88]

I only used BR2s in my 7 SAUM and 7 SS so never realized what a difference it could make going from 250s to the BR2s.......Especially the increased velocity with BR2s in my particular gun.

Your velocity will come down with the BR2's

 

[jraulsten]

Your velocity will come down with the BR2's

I would have thought so, but I actually had to decrease my load by a full grain to get essentially the same velocity I had with the 250s……

 

[Mikecr]

Everything about primers is an abstract -because it isn't only about primers.
There is optimum striking, or further from it, with different primers and YOUR striking.
That's why it's a load development prerequisite to test this for optimum.

So you stumbled into a better primer for your striking, and stumbled into a better charge using that primer.
All backwards from how it should go, but happy for your luck.

 

[jraulsten]

Everything about primers is an abstract -because it isn't only about primers.
There is optimum striking, or further from it, with different primers and YOUR striking.
That's why it's a load development prerequisite to test this for optimum.

So you stumbled into a better primer for your striking, and stumbled into a better charge using that primer.
All backwards from how it should go, but happy for your luck.

Thank you for the backhanded compliment

 

[Mikecr]

We're all in the same boat really.

 

[ElkSurgeon]

I visited with LongTine & tried some BR2s in my 7saum. Ended up with an SD of 4fps on the Magnetospeed. Was unreal. Then put it on paper without Magneto cause if POI shift & my groups were like 1 1/4. Had to go back to 215m

 

[Coyote Shadow Tracker]

Br2s are my primers in .260, .270 wsm, 325.wsm, .243 with using H-4350 in all.

 

[MagnumManiac]

I have said this on this forum many times…primer testing is just as important as powder testing. All types of primers should be tested, both standard and magnum regardless of case size or powder amount used. I run standard WLR primers under 120+ grains in my 338-416 Rigby Improved 45° without issue, never had a hangfire or FTF using them or Fed 210's when testing. The WLR produced the tightest groups.
The only primer I've had issues with were Rem 7 1/2, they are cold.

Cheers.

 

[jraulsten]

I have said this on this forum many times…primer testing is just as important as powder testing. All types of primers should be tested, both standard and magnum regardless of case size or powder amount used. I run standard WLR primers under 120+ grains in my 338-416 Rigby Improved 45° without issue, never had a hangfire or FTF using them or Fed 210's when testing. The WLR produced the tightest groups.
The only primer I've had issues with were Rem 7 1/2, they are cold.

Cheers.

I agree that primer testing is just as important as powder testing but in this case I had no reason to change other than the fact that I am extremely anal by nature and can't leave well enough alone.......Gun shot consistent .2-.3s and was spot on to 975 yards (farthest I've shot it) with the first primer.

 

[lancetkenyon]

I have seen it happen with switching from CCI450 to CCI BR4 too.
FPS was close, but a lot more pressure with a 140 Hyb in my .260AI. And accuracy was hit or miss. Yet ES was significantly better.