issue with small base die or ???

[queen_stick]

I either have a funky die, or my brass may need to be retired?

details:

6mmbr
Lapua brass
HEAVY loads for 1K br shooting.
Chamber is minimum spec (tight)

After about 5 reloads, my brass is still stiff going into the chamber (tight bolt closure) AFTER full length sizing. It's not shoulder bump, as I can bump them back .010" and it's still tight. The cases are too fat down around the case head/webbing area. SO, I ordered a small base die.

Unsized cases are measuring .4727 (avg) at the base of the casing (right above the extractor groove). After using my small base die, they are measuring .4699. That part is all fine and ok, however the bottom of the die is actually shaving the case body in the process. There's a little ring of brass in the extractor groove (shaved of the side of the case) after sizing. And, the sizing process is very tight... takes quite a bit of force on the press.

I'm thinking this brass is expanded too far, before trying to save it with the small base die, but I'm really not sure. I would love to hear from the forum gurus about what's happening here.

Walt

 

[LHSmith]

Sounds like the reamer used was for 6 mm BR Remington brass., and not the Norma version

 

[queen_stick]

Sounds like the reamer used was for 6 mm BR Remington brass., and not the Norma version

and which one does Redding use to make their die?

 

[Laurie]

Sounds like the reamer used was for 6 mm BR Remington brass., and not the Norma version

Yes, I'd agree with that explanation - same thing happened to me. The proper answer is to get the smith to hone the chamber out a little if you want to use Norma or Lapua brass. As we never see Remington 6BR brass in the UK, I tried the small base die solution (Redding SB body die) and found it worked very well provided I used it on new cases. Keeping loads sensible saw it only needed for the first loading and a Forster FL sizer worked fine as a body die afterwards, a factory custom version used with the neck-section honed out to suit my brass and chamber.

That was for my chamber and brass though. About a quarter or third of new Lapua (gold box) cases were OK, maybe half a little tight and a quarter or so really tight especially on extraction. (So much so I took a soft-face mallet with me to the range - tapping the bolt with such gets Range Officers real nervous abouyt what sort of pressures they think you're running, as well as it being a PITA.)

I wouldn't like to say the small base die solution would always work. You're talking tiny amounts of interference fit here and a variance of a couple of tenths of a thou' either way in chamber + brass dimensions might change things for better or worse.

 

[LHSmith]

FWIW- I have a minimum spec chamber in a .222 and it is a PITA. I will refrain from using tight spec reamers in the future. I offer this info on the chance you decide to set the barrel back a bit and re-chamber to the Norma cartridge.

 

[queen_stick]

FWIW- I have a minimum spec chamber in a .222 and it is a PITA. I will refrain from using tight spec reamers in the future. I offer this info on the chance you decide to set the barrel back a bit and re-chamber to the Norma cartridge.

I had a discussion with a friend of mine about this exact subject. Tight spec chambers are a major PITA. I agree with that 100%!

 

[bglenn]

For me I like to have the bottom of the case (where you are talking about) about .001 smaller than they go in the die. You could polish a little off the bottom of the die (inside) and make sure there is a small radius at the bottom. Then size with this die every time. When you are finished you have a custom die. You can't measure the area because of spring back of the brass.

 

[Turbulent Turtle]

It has been my experience that if you try to use a small base die after several loads, you will not get the benefit you were hoping to get with the die; if the OD at the base has increased, the small base die will not shrink it back.

However, if you start with a smal base die from the first relod, you are able to control that expansion, but you must use it every time.

 

[Old Navy]

Sounds like your heavy loads have expanded the web area (right above the rim) of the case. You cannot re-size this area. That is why you are shaving brass. Even .0005" expansion is too much. Later! Frank

 

[queen_stick]

thanks guys.

I guess I have a bunch brass headed for the scrap bin... Brass is cheap compared to the possible effects of case head separation.

I intend to polish the edge of the die, and use that die every time on my new brass. if only they made a small base bushing die so I didn't have to size all the brass twice

 

[Turbulent Turtle]

Redding offers a Small Base Type S bushing die for the 6mmBR Remington as part no 77201. They also have one for the 6MM PPC, and of course for .223 and .308. I have been using the last two for several years.

 

[queen_stick]

no shit! didn't know that. gonna have to pick one up.

 

[Keith Hansley in NC]

Walt,

I may have a cure-------------PM inbound


Keith