30 cal match boat tail bullets!

[BT Sniper]

Been working on the 30 cal dies and the challenging boat tail base punch. Think I just about got it perfected. Check out the results.

Here is a look at my 30 cal 10s ogive 9 degree boat tail with .075 meplat bullets with the Sierra 175MK bullet in the center

http://i636.photobucket.com/albums/uu87/BTSniper/4e5bf28a-b204-4955-a8f3-e42348a56331_zpszzbhppsv.jpg (http://s636.photobucket.com/user/BTSniper/media/4e5bf28a-b204-4955-a8f3-e42348a56331_zpszzbhppsv.jpg.html)


http://i636.photobucket.com/albums/uu87/BTSniper/e20698ec-d261-4fa8-8376-601c62c07a5e_zpsprxznrmz.jpg (http://s636.photobucket.com/user/BTSniper/media/e20698ec-d261-4fa8-8376-601c62c07a5e_zpsprxznrmz.jpg.html)



Here you have the Sierra 175MK bullet next to my 6.5 ogive, .092 meplat, boat tail bullets made with RCE jacket, drawn down 9mm and a flat base FN 5.7x28 (made from the same dies, flat base punch of course) Had this been a .062 maplat the bullet would be very close to the 175SMK
http://i636.photobucket.com/albums/uu87/BTSniper/91781f0a-36f6-4d2a-a456-f76482e64c2e_zpsjqm4af9u.jpg (http://s636.photobucket.com/user/BTSniper/media/91781f0a-36f6-4d2a-a456-f76482e64c2e_zpsjqm4af9u.jpg.html)


http://i636.photobucket.com/albums/uu87/BTSniper/3e818f9f-eefc-4252-ad5b-68815f5fffaf_zpszi3ipsoy.jpg (http://s636.photobucket.com/user/BTSniper/media/3e818f9f-eefc-4252-ad5b-68815f5fffaf_zpszi3ipsoy.jpg.html)


Here is a closer look of the SMK on the left next to my 6.5S on the right.
http://i636.photobucket.com/albums/uu87/BTSniper/9e64e282-ed25-4285-89cc-94f7a50a39af_zpsr7bfri0g.jpg (http://s636.photobucket.com/user/BTSniper/media/9e64e282-ed25-4285-89cc-94f7a50a39af_zpsr7bfri0g.jpg.html)


Good shooting and swage on!

Brian

[IllinoisCoyoteHunter]

Very nice! Those look great!

[clodhopper]

Picked them up today at the post office. The mail man waited until yesterday to see if I would sign the sorry we missed you slip so he could leave it at my mail box.
The box is 1\2 mile from the house, the medium flat rate box would have set on top in plain view of all kinds of disreputable people passing by while my other time comittments would have left that box out there for 3 hours after dark.
I was okay with waiting a few more days until I could pick it up at the post office intact.
Have not got to use any of it yet, but the weekend is coming.

[BT Sniper]

Glad you received everything.

Look it all over carefully and be very carful with that boat tail point form base punch.

BT

[runfiverun]

Mark:
let me know how these work and the jacket length you use.
I have some longer jackets that would be about right for a 180-190 gr bullet.
I could send you up a handful if you want when I get home.

[kweidner]

Brian,

I am assuming this base punch is why most die makers do not offer a boat tail other than a rebated. do you have a picture from the top,of the punch so we can see just how delicate that rim is? I often worry about my RBT and how easy it would be to damage it. I would be interested in comparing the two.


thanks

[BT Sniper]

I'll get a picture up after the weekend. Yes, imagine your RBT punch with the edges extended out to a very thin sharp edge. I'm actually going to be experimenting with some sort of floating sleeve that will be held in place over the boat tail base punch protecting it until the bullet enters the die and the sleeve is then pushed down and out of the way allowing the bullet and base punch to enter the die in perfect alignment free from any damage, think of the primmer systems for our reloading presses, how it holds the primmer in place till it is seated in the case.


What I would be really curious to know is how the commercial bullet makers, Sierra, Hornady, etc. can make these boat tail bullets in there big presses at such high rates of production? How do they keep from dinging up this delicate boat tail base punch?

BT

[clodhopper]

I'm going to guess the commercial bullet makers are very focused on alignment.
I have not even taken the boattail punch out of the protective package yet. I made a few bullets from 5.7 brass.
Sized them down then seated cores without re annealing. The result was poor quality bases of uneven dimensions.
I plan to size down some 5.7 brass, and some .380 brass this weekend. Should be able to clean them and get them dry enough to work by next weekend.
Having some trouble with the core swageing, at least some of it is tracable back to core mold not fully closed before pouring.
The thickness of the walnut hill top strap, and the threaded bushing make it quite a ways up in there the core needs to be aligned perfectly to enter the die before deforming. Might have to drill a bleed hole in the lock ring.
Thanks for the offer Lamar, Should be getting some jackets from RCE soon, going to stick with 175 and down, my 30 cals are just 308 and .30'06.

[runfiverun]

Their .95's make a nice 152 gr soft point with a 116gr core.
I am starting to work up some loads to use for deer hunting in the 0-6
with this set-up.
The sAme 116gr core works super nice with the 5.7 brass and makes a very accurate 175 gr hollow-point.
I fill the nose with tumbling media (and anneal the nose ) of these and use them on rock-chucks.

[clodhopper]

Do you anneal the nose by dipping it in the lead pot?

[runfiverun]

No I done the same as I did for my 223's and drilled a board so that the base dropped in the holes and left the front third exposed.
Then I anneal the front third with a torch and run through the pin tumbler and go from there into the media tumbler with a little nu-finish.
This makes the thinner cases super soft in that area and the media filled tip acts as an initiator
it is a little overkill maybe but who else
makes a 175 gr varmint bullet in 31 caliber

[aaronraad]

I'll get a picture up after the weekend. Yes, imagine your RBT punch with the edges extended out to a very thin sharp edge. I'm actually going to be experimenting with some sort of floating sleeve that will be held in place over the boat tail base punch protecting it until the bullet enters the die and the sleeve is then pushed down and out of the way allowing the bullet and base punch to enter the die in perfect alignment free from any damage, think of the primmer systems for our reloading presses, how it holds the primmer in place till it is seated in the case.


What I would be really curious to know is how the commercial bullet makers, Sierra, Hornady, etc. can make these boat tail bullets in there big presses at such high rates of production? How do they keep from dinging up this delicate boat tail base punch?

BT

How are you spec'ing your core seating die relative to your point forming boat-tail punch? I noticed there is a difference in your boat-tails from the first picture either side of the Sierra, in length if not base squareness. Not that I make a true truncated conical boat-tail myself, I'm happy enough with a double taper rather than the rebated boat-tail. I've got my suspicions regarding a fully stepped RBT vs standard boat-tail (in terms of accuracy/long range BC) as I've never seen any documented evidence supporting the claims of the RBT.

Commercially I suspect that are 3 ways.

First is easy, short sharp boat-tail that allows enough meat behind the punch tip to stand-up to a normal production run (e.g. Nosler BT etc) but not really looking for long range BC and accuracy.

Secondly a die set-up that splits at the ogive or effectively the same, with an ejection pin that is full ogive sized. The die would also be made to nearly exact calibre and weight. Similar to Corbins blind die set for the FX-1 and FX-2 series.

Third set-up would be similar to one used by Simonson in his article a few decades ago. Basically you want to reduce the forming pressure all the way along the line right back to the lead core. Essentially you preform everything as much as possible to fit so you use the minimal amount of pressure at each successive stage. So cores match the jacket shape and ogive. Jackets are preformed with the boat-tail before core seating. Boat-tail punch fully supported and guided into point form die. This means the fit of the punch along the die wall has to be exactly parallel as soon as the punch comes under any back-pressure. Hence why the ogive is sometimes done in two/multiple stages to avoid pressure from a single stage long ogive. Anything to reduce the force required from the ejection pin and the boat-tail punch. This last method requires a lot more than the basic 3-die set-up obviously but I believe is most likely to achieve the base concentricity tolerances required.

That's my stab in the dark anyway. Can you imagine if there was an industry expert (e.g. ex-Sierra employ) as a castboolits/swaging member, they'd never have a chance to get away from the keyboard responding to all the questions!

[runfiverun]

I wonder if they form the jacket into the BT in one punch and die set.
and then insert the core in the seat die with the same rebated shape at the base.
This would easily punch in and out on the press.
Then point form with the same shaped rebated punch to square everything up.
If I were making them on a high speed machine set up for super long runs,
I would be doing something like that.

[BT Sniper]

Good eye there Arronraad with the different length boat tails pictured above, it was actually two different boat tail base punches used during final point forming, and some good ideas on the commercial operation of making boat tails.

I'll get it perfected even more so soon enough. Got some new ideas to try out.

BT

[aaronraad]

Good eye there Arronraad with the different length boat tails pictured above, it was actually two different boat tail base punches used during final point forming, and some good ideas on the commercial operation of making boat tails.

I'll get it perfected even more so soon enough. Got some new ideas to try out.

BT

Larry Blackmon makes and adjustable core seating ejection punch which you need when changing boat-tail length. Matching the length and angle of your boat-tail in the core seater with point-form punch is important. They are not an exact match, but you need to hold them within a certain range or you will start to see significant changes in your diameter across the base/shank junction, which is critical for sealing.