Jacket length vs. bullet weight

[rossi]

Hi to everybody,

I’m new to bullet swaging and need some help in choosing the right jackets. I want to swage 168 and 150 grains .308 bullets with a 7S ogive. I have to buy jackets, I thought about J4, in fact I do not know any other source.
But I don’t know what length I need to buy.
Anyone can help?

[talon]

It's a basic thing to keep records for every lot of bullets you make. Size and length of core, make and length of jacket, and all the details involved. While I don't have a 7S .308 PF die, here's what I used for 6S: for a 150 grain Lead tip, use .90" Speer jacket. For 168 gr Open Tip, use 1.025" long jacket.  If you have a supply of longer .308 jackets you can cut (file?) a few them down to about those lengths and run a few test bullets. A lot depends upon the amount of lead you want showing at any 'lead tip' bullet you make, or how far recessed you want the core in an 'open tip'.   

[Rick Teal]

I have 6S .312 dies, but I start with the same jackets used for .308 bullets.  My bullet design includes a somewhat open (hollow) tip before i insert my tip in them.  My tip weighs 14 grains, and the lead is set a fair distance back from the mouth of the jacket.  I can use a 1" jacket and produce a 168 grain bullet.  My experience with my .35 calibre bullets is that the weight is almost identical if I make them with my tips, or if I fill the jacket with lead and end up with something much like a Mag Tip.

I've estimated that a 1.1" jacket would produce a bullet a little over 180 grains (though I haven't tested this).  I've never considered making lighter bullets.

I use .030 jackets made by Butch Hairfield.

[rossi]

Thanks,

When I ordered my set of dies (I still have to receive them)  I chose from a list, and with the .308 dies the pamphlet said “can make up to 168 grains flat base and use up to 1,200 inch long jackets” so my conclusion was 1,200 jackets for 168 grains. But I was just guessing. I suppose that adding a boat tail will reduce slightly the weight I can achieve with a  given jacket length. Right?

[talon]

rossi, did you order a boat tail set? Yes, a  Boat Tail ( or RBT) bullet the same length as a flat base bullet, given all else is the same, will be a few grains less in weight. But, more importantly, make sure the jacket supplier knows you'll be making BT or RBT bullets, as some jacket heals are too thick to make those type of bullets. A .308 jacket 1.2" long is good to make bullets at least up to 200 grains. FYI: If a die maker says his dies are good for a jacket up to 1.2" long, that means that the minimum cavidy debth of his dies are 1.2"+1 caliber, which is, in your case, 1.508" (it takes about 1 caliber for the die punch to become stable enough in the die body before swaging force can be applied.)   

[iiranger]

Bullet jackets are not all that common. brunoshooters.com has J-4s at good prices, usually and sometimes Sierra. Sierra also makes and sometimes has jackets available. Mr. Harrifield is the other source and I don't have his e info at hand. Usually Mr. R. Corbin (rceco.com) will give it to you for the asking. Amazingly, jackets are not uncommon on ebay and sometimes you get a real "buy." But you have to search.

Since you are making your own, I would encourage you to think hard about one length and vary the weight by core size. Stability of a projectile for a given twist will be dependent on length. With the bore "setting" width/diameter... length is all you got. If necessary, use a bit of filler in the nose to support forming, ... IMO    luck

[rossi]

I am waiting for a flat base set and an additional boat tail forming die. I want to try both. I have seen Sierra sells .30 cal jackets,  1,155 long, on their site. I think I will try them, along with J4 1,150 and 1,080 long jackets.

What might be used to fill the tips while forming? I think something that can be easily removed, right? Something like wax, that can be melted away?

[475AR10]

Rick,
Above you spoke of using your bullet tips, are they poly? do you make them your self, if not do you know a source to get poly tips?

[Rick Teal]

475AR10:

No, my tips aren't poly, they're made from inverted .22 calibre jackets that I reduce in diameter and form myself.  I partially fill the inserts with lead to anchor them in place and retard expansion and increase penetration after the initial pneumatic expansion of the tip.

I don't believe there is a source of poly tips anywhere.  The investment in an injection molding machine is cost prohibitive for the home swager market.  If you knew someone with a machine that has some down-time its possible you may be able to reach some kind of agreement.

Something I've considered, but haven't tried yet is to get some poly rod and:

a) cut it to length, and cut both a point on it as well as a beveled groove to accept the jacket top, or
b) simply insert it into the bullet as a square tipped rod, and form the case with a flattened tip (similar to the mag-tip) with the plastic tip flush with the top of the jacket.