6BR pressure signs low loads

[boltfluter]

The first thing to do is eliminate either the case or the powder, then you can focus on the final problem. At least this is how I would move forward. Keep us posted on your progress.

Paul

 

[Walt Schmidlin]

Wild ass guess, have you checked your scale with a know weight?

 

[darkangel_r2]

This is 2x fired brass… no issues with fire forming the brass

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.

 

[Dolomite]

Wild ass guess, have you checked your scale with a know weight?

Yes checked with 2 digital scales.

 

[Dolomite]

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.

The bolt lift was heavy just no ejector marks on the case head which should be normal blowing out the shoulders.

 

[Dolomite]

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.

 

[243winxb]

bullet seated above the NSJ

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.

 

[moondog]

My BRA and BR fired brass won't chamber. Sizing it in a Harrells, it's fine, 2960 and 2840 respectively. No hard bolt lift in either.

 

[Dolomite]

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.

 

[pdhntr]

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

 

[moondog]

The Harrells boys are great to deal with!
They'll set you up with a die that'll work great. Plus, you get a bump gauge with it!
You'll be happy

 

[Dgd6mm]

I thought I read in the past where they pick a # die. Is this so or am I thinking of a different company?

 

[Dolomite]

@SPJ @moondog Would you happen to know how much does the Harrells die size the neck?

 

[Dolomite]

When I ordered a press I offered my card number for payment, guy says no worries the invoice will be in the box just send a check.

They are bushing dies , so you can tune your neck tension to what the rifle wants.

Ahhhh so they can use the Redding bushings?

 

[davidjoe]

In the past, there has been such an unlikely thing explored, - aptly referred to as a squeeze bore - with a gradual taper to a smaller diameter at the muzzle. While I would expect, with no experience within this hypothetical, - much more severely dramatic effects than what you describe, - if a 5.56 barrel was accidentally chambered for a moderate size 6mm case and with a long free bore, such that it would chamber and fire, would it be possible that with a modest starting charge, there actually wouldn’t be a major malfunction and brass would just “age” at an exceptionally accelerated rate?

 

[jaybray]

Not sure if this has already been posted yet but I had the exact same problem with my 6BR and after many many hours of pulling hair out, asking questions and scouring the internet I found the answer. I was not wiping the case lube off the cases good enough and eventually enough lube had also built up on the chamber walls (which I also neglected to clean) that it created major high pressure issues. Many on here with far more knowledge than myself will know what im talking about. Anyway once i swabbed out my chamber real good and used brake clean on my cases after sizing no more problems. I found the answer to my issue on these forums. "Maybe" this is also the original posters problem as well.

 

[LCazador]

Ahhhh so they can use the Redding bushings?

Harrells dies pretty much same as Redding and use either Redding or Wilson bushings. Is your chamber a Norma chamber or 6BR Remington chamber? 27 gr of Varget is max for 6BR Rem in the Berger book. Also the velocity for that max load with a 105gr bullet as stated in the Berger book is 2656 out of a 24 inch barrel.
Very similar to what you are getting. Do you have reamer print?

 

[Dolomite]

In the past, there has been such an unlikely thing explored, - aptly referred to as a squeeze bore - with a gradual taper to a smaller diameter at the muzzle. While I would expect, with no experience within this hypothetical, - much more severely dramatic effects than what you describe, - if a 5.56 barrel was accidentally chambered for a moderate size 6mm case and with a long free bore, such that it would chamber and fire, would it be possible that with a modest starting charge, there actually wouldn’t be a major malfunction and brass would just “age” at an exceptionally accelerated rate?

Interesting I do dry the chamber after cleaning the barrel. I use Hoppes barrel blaster.

I also tumble the brass in walnut to remove the imperial wax case lube. Maybe I’ll try the brake cleaner on the brass next time.

 

[243winxb]

I’m using a Redding type S die (.267 Bushing) and noticed that the base of the neck that is unsized is .2705 and I have a .272 neck.

Talk to Redding, if you think its the die. They may want the die back, with fired brass from your rifle.

 

[Dolomite]

Talk to Redding, if you think its the die. They may want the die back, with fired brass from your rifle.

Good point I assumed the bushing dies left a portion of the neck at the base unsized.