Reloading 6.5 CM help

[Stormin_67]

Trying to equate my factory Hornady 140gr ELD match ammo @2750

Trying both H4350 and IMR 4451 and begin blowing primers around 2670 ish

Using new Lapua brass and CCI small rifle magnum primers, what am I doing wrong? Should I try s standard velocity primer, if so what brand?? Thx


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[petree_777]

I have heard that the lapua brass runs high pressure. Just what I have heard. Have you tried Hornady brass?

[Stormin_67]

I have heard that the lapua brass runs high pressure. Just what I have heard. Have you tried Hornady brass?

Just the factory Hornady ELD 140's, haven't reloaded the brass. I spent way too much on Lapua brass if all I can safely get is 2650fps out of it


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[petree_777]

Just try the same load on Hornady brass and see if there is pressure signs.

[ocabj]

What diameter firing pin are you running?

[petree_777]

Also I have been getting great results out of r17. I'm getting 2925 fps with 140gn pills with no pressure signs.

[Stormin_67]

What diameter firing pin are you running?

Factory firing pin from a FN SPR .308 action, not sure what size??


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[Stormin_67]

Also I have been getting great results out of r17. I'm getting 2925 fps with 140gn pills with no pressure signs.

How long is your barrel??? Mine is 22"


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[Stormin_67]

Just try the same load on Hornady brass and see if there is pressure signs.

I was trying not to use Hornady brass, heard it has a short life when it comes to reloading. I could try just for test purposes!!


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[ocabj]

Factory firing pin from a FN SPR .308 action, not sure what size??


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There's a good chance you'll need to have the firing pin channel in the bolt bushed and the firing pin turned down.

I'm betting there is some slop between the outer diameter of the firing pin and the hole in the bolt face allowing some primer flow. Since a large primer has more surface area supported by the bolt face, you usually won't see issues.

You might already be seeing cratering on your large primer 6.5 Creedmoor loads, but nothing too severe.

But since Lapua 6.5 Creedmoor brass uses small primers, there is less surface area, so there is more pressure on that gap between the firing pin and the bolt channel.

When Lapua decided to go with small primer pockets on the 6.5 Creedmoor brass, there was some grumbling about this because people were concerned about having to get firing pins bushed on factory actions.

I could be wrong, and this may not be your issue. But if you show some of your fired brass to a gunsmith, they'll be able to figure it out.

[Stormin_67]

There's a good chance you'll need to have the firing pin channel in the bolt bushed and the firing pin turned down.



I'm betting there is some slop between the outer diameter of the firing pin and the hole in the bolt face allowing some primer flow. Since a large primer has more surface area supported by the bolt face, you usually won't see issues.



You might already be seeing cratering on your large primer 6.5 Creedmoor loads, but nothing too severe.



But since Lapua 6.5 Creedmoor brass uses small primers, there is less surface area, so there is more pressure on that gap between the firing pin and the bolt channel.



When Lapua decided to go with small primer pockets on the 6.5 Creedmoor brass, there was some grumbling about this because people were concerned about having to get firing pins bushed on factory actions.



I could be wrong, and this may not be your issue. But if you show some of your fired brass to a gunsmith, they'll be able to figure it out.

Interesting, thanks for the input, I will contact the builder of my rifle and see if a pic or description of my primers could be caused by what you discussed above.


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[SixPointEight]

I wouldn't use magnum primers, but I doubt that's your issue. Lapua has a lower case volume, usually see pressure signs at lower charges. You seem to be using appropriate powders, so I'll let some others chime in, but brass with higher internal volumes will take more powder (and usually more velocity) at reduced pressures. As much as you don't want it to be, the brass might be your problem

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[bsumoba]

There are many people I know that had to bush their firing pin. One was a R700 and another was a Panda action. They were shooting LR primers just fine, but when they switched to a 6 dasher (SR primer), they were getting pierced primers faster when working up a load, resulting in really low velocities.

My suspicion is you need the firing pin bushed. You might even consider going to to a smaller diameter firing pin when you get is bushed

[Stormin_67]

I will give my builder a shout tomorrow and load up some Hornady rounds. I have never noticed any cratering out of my factory Hornady brass and I have checked.


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[jayfarley3]

How much powder are you using? I'm getting good results with cci br4 and 41 grns of 4451. No pressure signs at all using a standard r700 bolt/firing pin. I'd try regular primers before you do anything to the rifle