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6BR pressure signs low loads

The .200 line is only a delta whereas the case body slightly further towards the middle is more telling if you turn your calipers lengthways.

I might turn the necks a bit to ensure a min of .003 neck clearance. There is no down side to having that extra ..

The .002 resizing your die is producing at the CSJ is about perfect, in contrast your .200 seems like it could benefit from a tad more than .4695, I would rather chamber freely than worry about clickers and pressure
You can send 3-3x fired cases to Harrel’s precision for a semi custom die at $90 it’s a steal.

Most of us br guys go with 105 class bullets running near 30 gr Varget at 2850 ish fps in a .100 free bore chamber.
I wouldn’t even worry about ES/SD until the barrel is broke in, I would just fire form a 100 rounds at 29 grains and then do a charge ladder with at least a couple thou of neck tension followed by seating test and then primers before returning to NT .
Jim
 
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1sickPuppy said:
Bolt face has no burrs I double checked. I’ll try another lot of varget.

I’m not sure why I get heavy pressure and low velocity. is that from the powder being too fast?

I wonder if I could color up a piece of fired brass insert it into the chamber and look for any rub marks? If not I’ll try and find a way to cut up the brass as you mentioned.

I do have a 308 small base die which I could try. Would it be sizing the upper body of the brass too small? The 308 small base die really squeezes the upper portion of the brass down a lot.


I believe the blown out shoulder is causing by the heavy pressure which is causing the heavy bolt lift.
Click to expand...
Yes, to a fast lot of Varget. A buddy has an 8 pounder that is unusable in his 6 Dasher. A standard .308 die is what I meant to say. Just sizes the base and nothing else. I honestly believe you have two problems going on here.

Paul
 
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One way to eliminate "powder" and/or "primers" is to load a few at an obviously low charge ... for several hundred fps lower ... and shoot them. If you still see the same pressure signs, then something about the case and/or sizing is the issue. Just a thought ... probably not very helpful.
 
1sickPuppy said:
This is 2x fired brass… no issues with fire forming the brass
Click to expand...
If you had no issue fire forming add some more clearance in the chamber (size the brass more) and see if its too tight in the chamber. I'd be surprised if thats it because your velocity wasn't great. Chamber to tight around the neck? Maybe turn a thou or two off the brass and try again.
 
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darkangel_r2 said:
If you had no issue fire forming add some more clearance in the chamber (size the brass more) and see if its too tight in the chamber. I'd be surprised if thats it because your velocity wasn't great. Chamber to tight around the neck? Maybe turn a thou or two off the brass and try again.
Click to expand...
The bolt lift was heavy just no ejector marks on the case head which should be normal blowing out the shoulders.
 
Update from the last test:

1. Squeaky clean barrel and dry chamber.

2. I didn't anneal the brass and the case mouth now measures .271 and a bullet drops freely in the fired case.

3. Shot 6 rounds 95 gr Berger's which had the base of the bullet seated above the NSJ (advice from another member) shot a sample with BR4 and 400 primers (Primers didn't make a difference) which reduced the heavy bolt lift. Going to test more on seating the bullet longer closer to the lands.

4. 29 grains 2750 FPS. (guessed at powder charge) not sure if this load is in the ball park in terms of FPS.

5. 3x fired lapua cases will not chamber after fired.

Took the advice of another member and colored the brass to see where it was hanging up in the chamber.

Found the the body just below the CSJ is where the brass is hanging up.
 
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1sickPuppy said:
bullet seated above the NSJ
Click to expand...

When fired brass will not fit back into the chamber it came out of, means a few things.
1. The bolt face is not square to the chamber.

2. The chamber is oval.

3. High pressure, no spring back of the brass after firing.

Yours is caused by high pressure. Seating a shorter buller at a longer COL, is removing the bullets shank from the neck shoulder junction.
This removed the pinch point. Turn the necks for a tight neck chamber or open the chamber to a no turn diameter.

Just how i see it. But not sure i trust these new glasses. :cool:
 
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Thanks guys, before I head down the neck turning path, what will the harrels die do to help? @SPJ & @moondog

will it size the body below shoulder more or less?

The reason I ask is I just received a Forster FL die and it sizes the body below the should smaller than the Redding Type S die.
 
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I called Harrells to find out exactly what I was supposed to send in for my 6Br die, and a nice lady answered the phone, and said she had to go in the back to get one of the guys to take my call.

A minute later she came back on the line somewhat flustered, "THEM BOYS WENT FISHIN'! I will have to have them call you back tomorrow". (they did)

Jim
 
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