I'd like a fast but soft .308 bullet.

[qajaq59]

I'm wondering just how much difference a gas check does make? If i used a soft bullet that would give me good expansion, but normally would have to have a velocity of say 1200 fps, how much faster could I drive it if I put a gas check on it. I've searched around some, but I really haven't found anything definitive on it. There must be info about it in here somewhere.
Thanks

[Boerrancher]

When it comes to cast boolits there is nothing definitive, each gun/boolit/powder charge is a law unto its own. I would start out with a 170 gr WW boolit with about 2% tin added, with a gas check sized 2 thousandths over bore dia. For a powder charge I would start with about 37 grs of IMR4064. That should give you a starting velocity of around 2300 fps. or better. You can increase your powder charge until you fill the case with IMR4064 or get leading which ever comes first.

For my 30-06 I use a 50/50 pure and ww alloy cast into a Lee C309-180-R. I shoot this boolit with 54 grs of AA3100, for a velocity of 2500 fps. You can substitute IMR4831, or H4831 as well, though you may have to adjust the charge slightly. The size of your boolit and your lube are the critical components the next thing is using a slow enough burning powder to not exceed the tinsel strength of the alloy. It also helps to have your boolit seated out as far as you can. I hope this helps you out some.

Best wishes from the Boer Ranch,

Joe

[atr]

I have an older Ideal loading manual.....and I've noticed that for the same wt boolit the manual switches to a gas check whenever the velocities get above 1600 +/- fps and usually the boolit is listed as "hard" for the higher velocities.
But as Joe said, "each gun/boolit/powder charge is a law unto its own"...

[qajaq59]

Can I use the Lyman 450 to lube, size and put the gas check on that C309-180-R? or do I need the Lee sizer?

[Echo]

Your Lyman 450 will work just fine to seat the GC and lube/size your boolits. Seat the GC on the shank first, then insert into the H/I die set and have at it.

[qajaq59]

Thanks to all for the help.
I guess I'll order that mold from Lee today and give it a try. I'll also give the IMR4064 a try if my local guy has it.

[pdawg_shooter]

You want to move a soft bullet fast, Paper Pitch! You can take pure lead 2200fps or so and WW to 2500fps.

[pdawg_shooter]

You want to move a soft bullet fast, Paper Pitch! You can take pure lead 2200fps or so and WW to 2500fps.

Duh.... thats Paper Patch, never could type worth a hoot!

[docone31]

Dennis, I was waiting for you to pipe in.
I feel kinda bad proclaiming paper patching on this category. I do not know why, but I do.
I agree with Pdawg. If you want speed and accuracy, paper patch! Especially for the .308.
I am getting great results with that technique.
I could never get gas checked castings to do anything but litter the berm behind everyone else's targets but mine untill I paper patched.
How about 40.4gns of Surplus 4895 and 1" at 100yds!
Paper patch.

[runfiverun]

you can run a plain cast boolit at higher velocities too, but the softer alloys do need some help and paper patching is one way to get there.
i usually switch to a g/c at between 14and1600fps.
i am able to use 50gr. rl-19 behind a 245gr. boolit cast from ww's and pure, with 1% tin.
and no p/p.
however i am considering p/p in my model 700 8 mauser. just cause.

[oso]

qajaq59, have you slugged your rifle's throat yet? You might want to consider the Lee C312-185-1R instead of using the Lee C309-180-R and counting on the soft boolit bumping up if the throat is large.

[docone31]

I have accidently loaded the C312-185R in .308.
It did ok. The nose is .304, rather than .301 but it did not affect things. No primer pressure sign, and no excessive leading.
It does size down nicely.