First post, please be kind!

[wonderdog451]

Now those bullets seem to be pretty close to what I am looking at making myself, would you mind sharing the details about your manufacturing process?

[FatMcNasty]

corbin 6s 308 die set.
Normal Swage core to size. drop in a 1.25 length jacket. swage core in then tipping die till its almost a flat point with a hint of a HP. Of course cleaning the lube off between each step. nothing special really. i have yet to get out and shoot the test batch I made up.

[gunguychuck]

Why would a boat tail bullet give you nothing in performance with a subsonic round when the boat tail has no effect until the bullet has slowed to subsonic. QUOTE=Reload3006;1954216]on a subsonic projectile a boat tail will give you nothing in terms of performance. If you are going to make long range bullets that you want to stay accurate as the bullet transitions from sonic to subsonic flight a boat tail is the way to go. But if your never super sonic that boat tail gives you nothing but expense.[/QUOTE]

[JonB_in_Glencoe]

regarding using a 5.7x28 case for a jacket.
This thread of BT's talks about it.
http://castboolits.gunloads.com/show...-5-7x308/page3

I posted how I sized a cutdown 5.7 case using a modied 280rem FL size die,
Jon

[Reload3006]

The reason is aerodynamics as a projectile flies through a medium. In our case the atmosphere or (Air) it creates a vortex at the base of the bullet. this neither enhances or impedes the projectile until such a time as the projectile starts to transition from sonic to transonic flight at what time the vortex at the base of the bullet begins to shift. that is where the boat tail shape comes in. It has the ability to slip through this buffeting easier than a square base because the shape of the boat tail approximates the shape of the vortex essentially giving a smaller surface area at the base of the bullet to be buffeted. In subsonic flight there is no transition to subsonic flight so no buffeting or very minimal hence a boat tail has no effect.

[gunguychuck]

A boat tail bullet will reduce drag at all speeds but very little until the bullet has slowed below the speed of sound, when it reduces drag the most. A boat tail bullet does much more for a bullet going 1130 fps or slower than a bullet that is supersonic. This is from technical papers on Dave Corbins Website. Check it out.

[7of7]

The rebated boat tail, is designed to deflect the gasses away from the bullet, so it doesn't fly through the turbulence of the muzzleblast. The regular boat tail, allows the gasses to flow around and in front of the bullet as it exits the barrel, before the base exits.
I have Corbin equipment, I do make some of my own punches for my specific needs. Dave Corbin has been very helpful with tips on making the bullets, which shortens the learning curve.
I have two CSP1 presses, and 30 cal dies, 3/4E, 6S, and 8S point forming dies, as well as the RBT dies. I have also made a spreadsheet for bullet weight which will effectively give you the core weight needed for the finished bullet weight. Jacket weight is based on .05 increments, from .6 inches to the 1.25 length jacket.
Corbin jackets, have a thicker wall at the base, that extends .5 inches up the jacket, then the wall thickness decreases. This effectively gives you a jacket that will expand easily, and control that expansion when it gets to the thicker wall. I buy the bulk box of jackets when I buy them.
As far as cores, I picked up a 4 place adjustable weight core mold. So, I cast a core, swage it to the weight I need.. however, I swage a bunch for the bullet weight I use.
The 300 AAC, I would say is pretty close to the 30-30 as far as velocity. I think it would be a hoot to shoot.. (just have to get the upper, dies, and some brass...) I could seriously have some fun with that...
Also, short jackets... or long gas checks... work great. no leading, and don't need lube. I make my own gas checks too, and have used some with swaging..
When you have the equipment, the fun is just beginning.. I have quite a bit of fun with mine, and trying new things.. creating new things too.
But, I do have a large garage that has additional space for workbenches.

[Reload3006]

Daves brother Ricard disagrees.

[wonderdog451]

The rebated boat tail, is designed to deflect the gasses away from the bullet, so it doesn't fly through the turbulence of the muzzleblast. The regular boat tail, allows the gasses to flow around and in front of the bullet as it exits the barrel, before the base exits.
I have Corbin equipment, I do make some of my own punches for my specific needs. Dave Corbin has been very helpful with tips on making the bullets, which shortens the learning curve.
I have two CSP1 presses, and 30 cal dies, 3/4E, 6S, and 8S point forming dies, as well as the RBT dies. I have also made a spreadsheet for bullet weight which will effectively give you the core weight needed for the finished bullet weight. Jacket weight is based on .05 increments, from .6 inches to the 1.25 length jacket.
Corbin jackets, have a thicker wall at the base, that extends .5 inches up the jacket, then the wall thickness decreases. This effectively gives you a jacket that will expand easily, and control that expansion when it gets to the thicker wall. I buy the bulk box of jackets when I buy them.
As far as cores, I picked up a 4 place adjustable weight core mold. So, I cast a core, swage it to the weight I need.. however, I swage a bunch for the bullet weight I use.
The 300 AAC, I would say is pretty close to the 30-30 as far as velocity. I think it would be a hoot to shoot.. (just have to get the upper, dies, and some brass...) I could seriously have some fun with that...
Also, short jackets... or long gas checks... work great. no leading, and don't need lube. I make my own gas checks too, and have used some with swaging..
When you have the equipment, the fun is just beginning.. I have quite a bit of fun with mine, and trying new things.. creating new things too.
But, I do have a large garage that has additional space for workbenches.

I too, was always told that the Rebated Boat Tail on a bullet was there to deflect the gases from the propellant away from the base of the bullet and as an additional bonus, it had a slight improvement on aerodynamics. I really do think that the 300 Blackout is an excellent alternative to traditional SMG calibers and if I am going to stay with this caliber for any appreciable length of time, I would like to be as thoroughly informed about as many different aspects of it as possible. It is just too bad I no longer have a garage to convert into my new man cave, rest assured that if I did have one, it would be set up for reloading rifle,pistol, shotgun and bullet swaging and casting.

[Reload3006]

From Richard Corbins swaging book
Rebated Boattail Bullets
The rebated boattail bullet is usually made by home bullet makers. There is little advantage or disadvantage between the standard boattail and the rebated boattail. Barrel life will be the same, accuracy is the same, ballistics are the same.
The reason for the rebated boattail is that the tooling that makes the bullet will last much longer and is not as easily damaged as that for the standard boattail. The punches that form the rebated boattail are enough stronger that they will be more forgiving of the occasional “oops”. The rebated boattail is simply a much better design for home and small commercial bullet makers.

[nhrifle]

I love my Blackout and shoot it every chance I can. It digests everything I feed it with no problems whatsoever and is very forgiving.

As far as the boat tail is concerned, I would say go with whatever bullet style you like best. If that RBT style looks awesome and you just have to make em, go for it! Certainly can't hurt. However, my personal recommendation would be to go with a flat base design as tooling costs are less and I honestly havn't noticed a difference in practical accuracy between FB and BT until I cross 800 yards or so. That distance might be a stretch for subsonic loading!

Also, try some cast boolits in yours. That's mostly what I shoot, and I've found them to be just as accurate as jacketed. A couple great moulds are the Lee C312-155-2R and the Lyman 311299. Both are minute-of-squirrel accurate at my plinking distances (under 200 yards) and I have yet to have any bad leading of the barrel. My initial fears were that the gas tube would foul with lube and lead, but the gas system stays clear.

A final thought. The neck length on the brass is short and subsonic bullets tend to be long, so I would recommend a long ogive on your projectiles, somewhere around 8 or 9, to give best feeding in magazines. Both Barnes and Sierra have bullets made specifically for the Blackout. Take a look at those and you will see what I mean.

[BT Sniper]

Here is what I came up with for a customer's idea for a good 300AAC bullet. Think it was a 200 grain lead bullet with small gas check jacket next to a 180 grain nolser BT

I would imagine that bullet should expand well at sub sonic speeds

BT

[nhrifle]

BT, that looks interesting, but what about the chances for leading with all that exposed lead and no lube grooves? Maybe I'm not seeing something right but that would be a worry of mine.

[wonderdog451]

BT, that looks interesting, but what about the chances for leading with all that exposed lead and no lube grooves? Maybe I'm not seeing something right but that would be a worry of mine.

I was thinking the same thing, what are the chances of the barrel getting leaded by a projectile with with no lube grooves and jacket Or will that not be an issue with a subsonic bullet? I also saw the specifications for the new MSAR Stg 556 E4 rifle that has a soon to be available option of a 16.5" 300 Blackout barrel and am thinking that a heavy 30 caliber bullet at subsonic speeds out of that weapon will be devastating.

[Mountain Prepper]

First - welcome to swaging (or more kind would be to shout a warning and have you run away as fast as you can).

Ok, so it is not so bad... but like casting - this entire "roll your own" can get addicting - I have left in my personal collection three corbin swage presses of various designs. I have been selling off my unused swaging equipment a little at a time (some things I just do not shoot enough to bother with.

If anyone is interested I have a full set of .308 8sVLD dies with the two die RBBT added dies available and possibly a press to go along with it.. My eyes are no longer my friends and my days of long range shooting are just about over, I will be shortening my distances and concentrating on hunting bullets (have a set for that in .308) and hopefully retirement hunting in less than a decade. PM me if anyone is serious about a set in excellent like new condition without waiting, the price will not be cut rate, I would rather not sell if that were the case.

[Mountain Prepper]

From Richard Corbins swaging book
Rebated Boattail Bullets
The rebated boattail bullet is usually made by home bullet makers. There is little advantage or disadvantage between the standard boattail and the rebated boattail. Barrel life will be the same, accuracy is the same, ballistics are the same.
The reason for the rebated boattail is that the tooling that makes the bullet will last much longer and is not as easily damaged as that for the standard boattail. The punches that form the rebated boattail are enough stronger that they will be more forgiving of the occasional “oops”. The rebated boattail is simply a much better design for home and small commercial bullet makers.

One other benefit of the RBBT bullet is simply a shorter "shank" so the extra weight of lead in the BT will not have the same pressure effects as one of the same weight and a flat base (longer shank).

I certainly did see a great effect when I started making RBBTs but that could be simply that I have much more control over the bullet weight, jacket, jacket weight, core and everything else - and could be similar to hand loading - when you do it yourself and control everything you get a higher quality product... Only bullets that come close are the custom swaged benchrest bullets, and I have an edge there in that I can modify further to match the exact rifle.

[MUSTANG]

I was thinking the same thing, what are the chances of the barrel getting leaded by a projectile with with no lube grooves and jacket Or will that not be an issue with a subsonic bullet? I also saw the specifications for the new MSAR Stg 556 E4 rifle that has a soon to be available option of a 16.5" 300 Blackout barrel and am thinking that a heavy 30 caliber bullet at subsonic speeds out of that weapon will be devastating.

Low velocity, the 300AAC is at 1000FPS (+) in a 200 grain bullet. Seems that other than shape, it would be in the same range as a .41/.44Mag less the lube groove/s. Perhaps a Lee Tumble Lube or other similar lube, or a Moly will provide sufficient film lube to preclude leading. (Think over sized 22LR, similar velocities, but ratio of surface area is much greater for the .308)) The swaged Gas Check should protect against gasses.

I had thought about the same concept in a low velocity .308, swaged lead .308 bullet using gas check at bottom, making bullet using a set of CH .308 dies I bought 5 years ago but have not explored to date.

Mustang

[nhrifle]

I saw somewhere that Lyman has a moly spray that would work as you describe Mustang. Of course, in a low pressure, low velocity load leading may not be an issue despite my earlier fears. My airguns shoot raw, dead soft unlubed led pellets anywhere between 1300 and 1500 fps and I have yet to remove any leading from the bore.