Just got back my 6gt and just test fired a couple shots. Unfired brass was only .005 small than fired brass, I have never had such a tight chamber before. Is this too little?
Too little headspace?
- Thread starter Dmagna
- Start date
Help Support Long Range Hunting Forum
MagnumManiac
Well-Known Member
No, but you will have to plan to make good judgement on sizing, because it will be very easy to not size enough.
I have 3 chambers that are zero headspace, this requires sizing .0015" below SAAMI minimum, shell holders are turned down to accommodate this. Another is .002" above minimum and requires sizing to minimum, most dies are incapable of doing this correctly unless you plan. I use body dies and Forster BR dies with honed necks and keep neck expansion to .003" over seated diameter…match grade means just that.
Most don't calculate springback in their measurements, this is critical for PROPER sizing, and more clearance than necessary is not conducive to precision.
The biggest problem most make is to size excessively once they realise that the initial sizing has made the case longer and the brass won't re-chamber…avoid this at all costs.
Cheers.
Thanks. This is my first rifle with this small of a headspace. Thanks for the help.
elkaholic
Well-Known Member
We intentionally only run .002" head space from my brass to chamber on new brass. The reason .005 seems like a lot to you is because a lot of commercial ammo has far too much head space. They do that to make sure it will chamber in about anything, but its not a good thing otherwise. Its hard on brass and not conducive to great accuracy. If I were you, I would buy a shoulder bump gauge and not count on the std die instructions of letting the die touch your shell holder with the ram fully up. All that does is get you somewhat in the ball park. Brass fully formed in your chamber should generally be bumped about .002" and you can only achieve that with good measurements. If you don't measure, you can do a careful trial and error. Start with slight bolt close resistance and go back in very small adjustments on the die until there is no resistance, and you'll be close.
Thanks. I usually have experienced at least a .02 of expansion on non belted brass. Belted brass cartridges a little bit more. I have hornady dies for the GT. I think I will probably change them to the SAC dies or something with some better quality. But these should get me a ways
FireFlyFishing
Well-Known Member
Seems ideal to me.
BrBa.
Well-Known Member
Does the bolt close on a Go Gauge?
That's a huge chamber to me. Gigantic. Most of the ones I chamber for myself don't grow more than .001" after multiple firings.
MagnumManiac
Well-Known Member
SAAMI chambers run .010", so brass runs smaller than this when new. Even if the brass was undersize to begin with, this chamber is most likely .003" above minimum.
Cheers.
I chamber all my personal to .002" longer than the brass I intend to use.
