30 Gibbs, 30-06 JDJ?

S

saudst

New member
Hi People.

I have a project that my son and I were going to tackle and have some questions you all might help me with.

1, Have any of you loaded either one of these and chronographed the loads? If so, what were your results? I came across these rounds in my Cartrages of the World and there seems to be a big difference between case volume and the velocities they are claiming, unless the Gibbs data was taken in a 36" barrel.

2, Because both of these rounds are a pushed shoulder design, can I just get 35 Wellen brass and create a false shoulder to headspace and fire form brass?

We have a Rem. 700 BDL 30-06 that we would have rebarreled and correctly headspaced and go from there, but I need to know which chamber would be the best as I know no one who know anything about either of them. I am not trying to create a 300 mag. just thought it would be an affordable project that my son and I could do together. I am pretty sure I want a 26" barrel and think this should add about 200-250fps. from the standard 22" factory 30-06. What are your thoughts?

Thanks for your time, Tim.
 
Saudst: Using 35 whelen brass would work, but you can use 30-06 brass you already have. You can expand the neck, and then neck down like you would with the 35 whelen brass. A .311 expander might be enough, but a .323 would be better. You might also consider using a cornmeal load to start the forming process, but reduced case forming loads wouldn't be a problem with either cartridge. While I've formed the 30 Gibbs, I have no experience with the JDJ, so I can't comment on it. I have seen the drawings of the JDJ and remember thinking there wasn't a lot of difference between the two. Either cartridge you choose will be a fun project.
 
Just trying to draw a parallel for you here. I saw the chronograph results of a 7mm Gibbs compared to a 280 Rem, and the gain was about 120 fps (4%+/-) using about 15% more powder. You could gain the same amount of velocity by putting a longer barrel on the rifle, as you are already considering. If the Gibbs really turns you on, go for it, but with today's powders you can almost match most of the improved cartridges by just finding the right powder.

As far as forming the cases, yes, you could use Whelen brass, but you still need to fireform the brass with reduced loads. Or you could form the shoulder like sadsack suggested and fireform. Same results, in the end.
 
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Thanks

Thanks guys, I think I'll call JD this spring when I have the finances for this. I think it would be better to go this route as he has the latest data with the newer powders availible and will make it easier to work up a good load.
 
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