6BR Pressure Found Low Charge

[DanSavage]

.268 nk 68 grain bt. Old brass still showing sine wave.

I’ve tried to achieve sign waves over many cartridges with no success,, only factory ammo will produce a sign wave in my experience,,, what gives, I’ve tried everything from more clearance, more tension, less tension and less clearance lol

 

[Larry Koch]

I’ve tried to achieve sign waves over many cartridges with no success,, only factory ammo will produce a sign wave in my experience,,, what gives, I’ve tried everything from more clearance, more tension, less tension and less clearance lol

The only rifle calibers I shoot- 30BR, 30 major, 6mm ppc, and 6br. all show a sine wave. Now early on I had difficulties in getting there. You need a clean neck, a proper neck chamber fit, and your good to go. If the brass neck is harden annealing will help.

 

[Larry Koch]

I always get sine wave type powder residue on my reloads.

That’s it.

 

[MikeG08]

I took the barrel off and put another project I was having trouble with back on. I had a 308 barrel that was very inconsistent. Long story short the dowel pin was dragging in the shroud. That action is off to Speedy and I am putting that barrel on this one and restarting that project. If I have trouble with the barrel I get back from speedy I think the trigger puller may be the issue.. .. I will come back and update this thread once I have my new barrel and do some load develop.

 

[Schippergreg]

I didn’t go back through all of the posts so sorry if this has been answered but explain your heavy bolt lift. Is it hard to raise the bolt or hard to pull the bolt back? If you have to snap the bolt open I would guess that your die doesn’t match the chamber and it’s hanging up at the base.

 

[MikeG08]

I didn’t go back through all of the posts so sorry if this has been answered but explain your heavy bolt lift. Is it hard to raise the bolt or hard to pull the bolt back? If you have to snap the bolt open I would guess that your die doesn’t match the chamber and it’s hanging up at the base.

It does it on virgin brass. On my fired brass I use a Cortina Mandrel which squeezes the base.
It’s a heavy lift up on the handle.

 

[gunsandgunsmithing]

It does it on virgin brass. On my fired brass I use a Cortina Mandrel which squeezes the base.
It’s a heavy lift up on the handle.

Are you familiar with bolt click and how it happens, etc? Is it that or is bolt lift heavy all the way through the lift?

 

[Schippergreg]

Sounds like a clicker to me. Strange that it’s happening with virgin brass.

 

[gunsandgunsmithing]

Sounds like a clicker to me. Strange that it’s happening with virgin brass.

Yes, really strange. There use to be some very tight 6BR reamers and ppc reamers. That would do it but most moved away from spec'ing around virgin brass a long time ago. Too tight is no good.