Making Cases for 30 Gibbs
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Timnterra
Well-Known Member
You will need to make an enlarged false shoulder before you load and fire form it. The reason for using 280 brass is the longer overall length which will net you a longer neck on the Gibbs case. However, the round will have excessive headspace if you just run it through the Gibbs die. In my brass prep I use a 338 neck expanding button to open up the neck then I run the brass into the 30gibbs die which leaves a false shoulder to headspace against in the chamber. With 280 brass You would probably need to run the brass through the 30 cal expander and then the 338 expander before you run it through the 30 Gibbs die. The other option is to seat the bullet way out and cram it into the lands, but I don't really trust the neck tension to hold the round in place like a false shoulder.
imyourhuckleberry
Well-Known Member
Since you have 30-06 brass, my Manual of Cartridge conversions states to "taper expand the '06 case to about .315 diameter F/L size in the Gibbs die. Square case mouth and fireform in the Gibbs chamber.
what velocity advantage does the Gibbs have over the 30-06?
.270/.280 gives you an additional 1MM length over .35 Whelen. I just did 100 .280 Rem from Peterson using COW over the weekend. The sizing, as noted by Tim, is exactly how to do it. I started a .30 Gibbs post a few months ago with plenty of information >>> https://www.longrangehunting.com/threads/30-gibbs-is-finally-ready.242088/page-14
You should end up something like the ones on the left and right ...
NOTE: Make sure you're trial run fits in the chamber before going further.
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It depends on your load combination. I am currently propelling the 190 Berger at 2806 FPS out of 24" barrel using RL-17, still have more room to spare. Just playing around with powder I have already open.
That is pretty impressive beltless magnum
whirlwindjml
Well-Known Member
What would r 26 do in that?
Also after you necked it up....could you hydro form it it from there?
Hot glue in primer hole.
Fill with water.
Insert case into die and press with decap pin out.
Drop .308 punch into neck through die hole and punch.
?
Also after you necked it up....could you hydro form it it from there?
Hot glue in primer hole.
Fill with water.
Insert case into die and press with decap pin out.
Drop .308 punch into neck through die hole and punch.
?
Instead of using hot glue, I use a spent primer.
Timnterra
Well-Known Member
Does that actually work as a hydraulic form die?
If your question is addressed to me using spent primer, yes, it does. I have John Whidden's custom hydraulic forming die for my wildcat, and it is what John recommends. Check out the video at ~1:28 minute mark ...
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whirlwindjml
Well-Known Member
So do you use the cream wheat after the hydro form? @ feenix
Negative! For pre-forming .30 Gibbs, I only use the COW method (). I use the hydraulic forming die on my .30 LARA. The picture below is with .35 Whelen brass ...
From L-R
1. .35 Whelen virgin brass. For .270 Win/.280 Rem brass, I have run a .309" and .339" expander mandrel first.
2. After re-sizing with .30 Gibbs sizing die.
(Prepped for pre-forming, with 11g WSF, COW to the false neck shoulder, and then stuffed with a cotton ball)
(COW pre-forming at the range)
(After COW method pre-forming)
3. After COW method.
4. After re-sizing with .30 Gibbs sizing die.
Let me know if you have any other questions.
