Boattail Bullets w/o the rebate

[30yrcaster]

Anyone know how Sierra, Berger, Hornady, Nosler etc. make the non-rebated boattail bullets? Only Laupa makes rebated boattail bullets and the design is from the '30's. Speer stopped selling the Speer/Lapua around '78. Speer Manual #9 had them then #10 didn't. Lapua's Scenar is their premier bullet, not the D46.
http://www.lapua.com/en/products/new-products/2

If you make the boattail punch thin enough not to have a rebate, the punch fly's apart. I wouldn't think it's proprietary since all the major mfgr's make them. Maybe the process it too expensive for the home swager to afford.

Berger did a tour of their plant on the Outdoor Channel this year but didn't actually show how they do anything.

Thanks

[williamwaco]

http://corbins.com/rbt.htm#whynot

http://corbins.com/rbt.htm


I have no idea what these cost.

I have been looking at this site for years but I could never figure out the price schedule.


Never mind. I mis-read your question.

[Wolftracker]

This is probably a proprietary secret of the manufacturers. Personally, I like the RBT and make them in 3 calibers for myself. My speculation is that un-rebated boat tails may be formed at the core seating phase in a die made much like a point former, but I'm probably wrong. So far, I've been un-able to prove or disprove the claims commonly made about the superiority of Rbt's. It's best to make a bunch of them at one time to get consistency as it may vary some from lot to lot. They tend to shoot accurately for me and the elk and deer don't seem to notice the difference.

[30yrcaster]

This is probably a proprietary secret of the manufacturers. Personally, I like the RBT and make them in 3 calibers for myself. My speculation is that un-rebated boat tails may be formed at the core seating phase in a die made much like a point former, but I'm probably wrong. So far, I've been un-able to prove or disprove the claims commonly made about the superiority of Rbt's. It's best to make a bunch of them at one time to get consistency as it may vary some from lot to lot. They tend to shoot accurately for me and the elk and deer don't seem to notice the difference.

Thanks for your thoughts.
Been to Perry many times and shoot with many high masters. Don't know anyone that uses RBT's. Back in the 70's yes but even then the Sierra 168 Intl Boattail Match were mostly used for 30 cal. Just recently army Seargent Green won Camp Perry and I doubt he used rbt's and he isn't sponsored. I know the AMU guys I've talked with use Sierra. I've shot plenty of my rbt's but at least in my rifles the Sierra's shoot much better @300 & 600.

Not trying to get into what's better, just would like to know how they make the non-rbt's. Like I said, maybe the equipment can't be ported to a hand press or isn't affordable to some of us.

[aaronraad]

You already know the answer 30yrcaster

Either you reduce the pressure exerted on the tip of a thin punch or you design a thick punch to take the load.

For a thin punch you need to make sure it's always well supported in the point form die, especially before it takes on any load. A thin punch is also assisted by preforming the boat-tail as close to it's final shape before it sees a thin punch. This means that the thin punch is engaging in the least amount of deformation work in the point form die and all you effort is focused on forming the shank, ogive and meplat.

For a thick punch, think of the Corbin die which is basically a blind die, which will split at either the ogive/shank junction or the ogive/base junction.

When you're running a 10-16 station BAM you learn how to take advantage of all those extra 'stations' to minimise the forces from each forming operation, or effectively you get use to replacing more tooling than you have to.

I'm a just a little bit over boat-tails, rebated or otherwise at the moment. My biggest gripe is identifying cracked punch tips because every punch will fail. A failed punch means a variance in my tolerances. A variance in my tolerances means a RBT or straight taper will be less accurate than it can be. I get horribly paranoid about punches that seem to last longer than the average when doing a batch run. I've found several now that have had hairline cracks in them as opposed to the punch that chips right out so that you can see them with naked eye or you feel/hear them go under load in the die. This means I have to go back through the batch and check all those that might be affected by the hairline crack. Boat-tails aren't all they're cracked-up to be!

[MFG_BOP]

Thanks for your thoughts.
Been to Perry many times and shoot with many high masters. Don't know anyone that uses RBT's. Back in the 70's yes but even then the Sierra 168 Intl Boattail Match were mostly used for 30 cal. Just recently army Seargent Green won Camp Perry and I doubt he used rbt's and he isn't sponsored. I know the AMU guys I've talked with use Sierra. I've shot plenty of my rbt's but at least in my rifles the Sierra's shoot much better @300 & 600.

Not trying to get into what's better, just would like to know how they make the non-rbt's. Like I said, maybe the equipment can't be ported to a hand press or isn't affordable to some of us.

I have a few carbide dies from George Ulrich. At the core seat stage a boat tail is formed, BUT the length is smaller and angle is a bit "bigger" than the punch of the point up die. This punch then, with the final BT dimensions, will make it look "beautiful" giving it its final shape and it is very thin, not a razor blade sharp, at the very tip. Breaks easily though if dropped. I think it may be heat treated and tempered???
Hope I've answered your question.

[runfiverun]

my money is on them using B/T formed jackets right from the start.
a B/T core seat die would basically final form the base.
then the point form stem wouldn't need to do much work other than point forming. [no stress]
let the dies do the work.

[supe47]

I have a boat tail die from BT Sniper. It is a boat tail core seat die accompanied with a VERY sharp edged point form punch. I have to admit, I've only run about a hundred bullets through the point form dies (both 6s and 9s) so I can't speak of punch life. I've wondered about how the big manufacturers do it, also. Seems like a punch that delicate would not last long under production conditions. Here's the first 5 I tried after receiving the die. I used a wee bit to heavy a core so I couldn't close up the tip the way I like. I did notice the pressure ring (visible just above boat tail) is slightly less than that of flat base. Straight from the PFD, not prettied up.

[30yrcaster]

supe47,
Nice looking boattails. What caliber are they?

Wonder why Corbin or RCE can't do the same. Would be nice to know how many bullets can be pointed before the punch flys apart. Maybe BTSniper figured out what the big guys already know and the punch won't fly apart.

[supe47]

Thank you. The bullets in my previous comment are .224". Boat tail length is also adjustable. Those pictured are at near max length. I do treat my PF die punch for the boat tails with kid gloves.

[BT Sniper]

I'm certainly getting it figured out. Just made some awesome looking 142 grain 6.5mm bullets with a beautiful boat tail. The point form base punch is........ well... pretty critical in all aspects when it comes to these boat tails. Has to be a perfect fit with perfect alignment, also has to be the right material of steel. It has a very sharp and very fragile edge to the ones I have been making, sharp enough to cut yourself.

Here is a look at the bullets I made this weekend, hope to get to shoot them soon. It is a 7.5s ogive nose with a 9 degree boat tail and .062 meplat made from RCE jackets. This bullet most closely matches the Nosler Custom Competition 6.5 match bullets. I have a reamer for the 11s ogive to closely match the SMK 142 grain bullet as well.











I'll have more info to share as soon as I get some time to actually go out and do some shooting. These 6.5 bullets have been a couple years in the process for my personal wish list of swage dies.

Good shooting and swage on!

BT

[30yrcaster]

Those are some sweet looking boattails!! How many bullets can you make before the PF punch begins to fail?

Thanks

[kc3ak]

I agree, BT, those bullets are awesome looking. I have never used a boattail bullet, but those sure look like they would get the job done. I love reading your posts, and learning from you. Thanks for your informative posts.

[rickv100]

In 1941, using a transfer press a boattail punch for a .50 caliber bullet had a life of 60,000 pieces. The transfer press took 4 stations to form the completed boattail.