350 Legend and Cast Boolits

[Oldfeller]

The B slider block cuts deeper than the A block generally speaking, and generally gets it all out of the way on just one pass. Don't waggle it around or try to dig deeper with it intentionally, you WILL dig a lot deeper real fast. B slider moves right along and you have to watch it at the lip end of the magazine or you'll cut completely out of the magazine because you weren't watching what you were doing ........

The C slider block removes the entire center long rib in one pass so don't try to manipulate it to cut deeper, you WILL cut a lot deeper real fast. C slider moves right along and you have to watch it at the lip end of the magazine or you'll cut completely out of the magazine because you weren't watching what you were doing ........

You will have to use the narrow edge of the flat bastard file to do fuzz cleanup duty in the nose area, and you can create some deep scratches off the sharp corners unless you are mindful when using the edge of the file. Good news is the bullet nose doesn't go in that deep, so any scratches are purely cosmetic and do not affect magazine function at all.


ADVANCED USES

You must cut all 3 of the ribs away before trying the following tricks ......

If you find you need to cut the A rib deeper at the start/base area and the tool doesn't seem to want to cooperate, install the B slider arrse-backwards in the magazine well and have the shaft sticking out from between the loading lips of the magazine side then re-starting your re-cut from the mouth-lip end the magazine and run it to the base opening. Be careful as you go along, as doing this cuts deeper --- sometimes more than you really needed.



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WARNING: Winchester factory stock 350 Legend brass won't load, stack and feed right from the 30 round converted 5.56 PMAGs. The extra head width of the Winchester brass causes a slow building "binding action" that stops the rib trimmed 5.56 mag from loading more than 10 rounds reliably. There are also issues with bullet nose forms and the narrow nose form of the 5.56 PMAG.

Simply wait until aluminum construction 30 round mags come out specifically for 350 Legend and save yourself the aggravation.




TODAY IS DECEMBER 19TH ---- THE PMAG RIB CUTTING TOOLING IS AVAILABLE FOR LEND

This tooling uses the most common plastic 30 round 5.56 PMAG as raw material for the trimming conversion to 350 Legend magazines.

I have cut all 3 of the ribs out of 8 plastic PMAGs now, and the instructions up thread have been tuned until they offer a pretty much flaw free set of "how to" instructions.

Send me a PM requesting to use the tools. Understand that you must have a real mailing address that you are willing to share and you must have a good image here on the list to have my tooling lent to you. You get the tools delivered at no charge, but you agree to PM message their arrival to you and to again PM the departure of the tooling when it leaves you to go to the next person --- and to pay the $9.99 small box postage to send it on to the next user. (flat mailers are damage prone and we don't use them as shafts can get bent and blocks can get crushed and broken when shipped in flat mailers)

So, using the tooling costs to you are about $10 (and the risk of that first plastic PMAG to your learning curve). That is the cost of a new small hard mailer box at the post office.

This is "tuned and adjusted" wooden block (re-enforced w/ JB Weld) tooling, with solid brass sleeve bearings, a HSS steel cutter burr head and a T-6 aluminum shaft to connect to your 3/8" drill. The shaft requires being lubricated with grease and it is easy to use (and also equally easy to mis-use) so try to follow the instructions.





WARNING: Winchester factory stock 350 Legend brass won't load, stack and feed right from the 30 round converted 5.56 PMAGs. The extra head width of the Winchester brass causes a slow building "binding action" that stops the rib trimmed 5.56 mag from loading more than 10 rounds reliably. There are also issues with bullet nose forms and the narrow nose form of the 5.56 PMAG.

Simply wait until aluminum construction 30 round mags come out specifically for 350 Legend and save yourself the aggravation.

[cwlongshot]

Anyone tried IMR4198 in the Legend with cast?

Looking thru my log tonight I see somehow I have never tried it and quick look theu my Maxi loads I dont see it there either.

4198 is a good CB powder in other calibers. Hoping it is here with this “legend”

My bullet is a Saeco 354 its a 180 as cast sized .356.


CW

[P Flados]

I remember seeing a few 4198 loads for the max. However, AA 1680 is the slowest powder commonly used in the max and 350L.

4198 is just slower than AA 1680.

AA 1680 loads are typically real close to 100% load density or they are compressed.

If 4198 is less dense than AA 1680 (my guess), normal compression may not be adequate to get the load up to the desired pressure range.

[cwlongshot]

Thats kinda why I am trying it. Max recommended is 20g and that dosent fill the case to bottom Of the bullet. There is slight air space. Knowing that most , best loads are 100% density I tried it in the Legend. I have found so far across the board max, maxi loads are fine in my Legend and have been safely increased. As we know the case holds more volume and its loaded to higher pressures.

Well Im gonna stop later today and send a few down range.

CW

[bikerbeans]

CW,

I tried both 4198 powders with 200g jacketed in the 357 max and the velocities were slow. I would expect the same in the 350L. IMO, both powders are too slow for the 350L or 357 max. As mentioned AA1680 is a good choice, and a safe choice too, either in the max or legend.

BB

[cwlongshot]

I love 16&0. Believe u me, tbere aint a load this boy aint fired.

Its not as good in the legend as it was in the maxi. Its OK... Not great conversly RL7 wasnt all
That in the Maxi but its been good in the legend. Its also a slow powder thats kinda what brought me to 4198

I dont want or need velocity. 14-1600 is plenty fro
My needs.

CW

[Oldfeller]

Gents,

I am getting ready to do a bit of mid-winter mold making. Since the steady on folks on this thread are pretty well known to me now I could see building two molds out for the Legend and putting one out to lend among ourselves.

The mold will be a 4 cavity cut on the larger LEE rifle mold block that Titan is now selling.

It could have 2 shorter cavities (located over the pins) and two longer cavities in the middle.

And by shorter cavities, that is everything up to the P Flados Big 'un in length. The two longer cavities could be anything up to a full sized High Ballistic Coefficient (pointy) subsonic. Such a long pointy bullet would be inherently unstable, relatively inaccurate over any longer distances and it would always want to swap ends inside the first 12 inches of meat penetration --- behaving similar to the 30 cal subsonic Blackout cast slug (except being MUCH MUCH bigger, of course).

Actually, it is even possible to cut a sampler mold with 4 different bullets in it (could be different calibers even).

Question for the group: What speed? What weight? What meplat size?

Bullets will all be a powder coat smooth form, so the gas check & grease lube guys need not apply.

[cwlongshot]

Well it appears to be a viable choice at least in my gun. Data came from a Contender manual and 20g of 4198 under a RCBS 180 Cast Sillouette bullet garnered 1559 fps from a Super 14”

All things equal (I know they are not) I should see about 75 fps increase.

Fully prepped Winchester cases primed W/S&B SR primers and IMR 4198 Powder. As seen very light loadings. Deep FP indentations. These primers come out of the box with a fairly sharp shoulder and appear flattened before firing. They also appear slightly protruded but they are not. There was zero case head expansion and resizing probably wasnt even needed. .

Again Bullet was a Saeco 354 180g TC powder coated and sized .356. These bullets are about a 15BHN.

Accuracy with the 20 shows good promise. 21 not so much.
One bullet out of group could well have been all me. Conditions where 19degrees. I did bring one sand bag but had no butt bag. Distance was just 50Y Site was Leupold 2/7 and I did not gave my glasses. This optic is a “shotgun” so its reticule is bolder then normal duplex Leupold reticule. No excuses here just facts. All Shots felt fine.

CW

[colonelhogan44]

Gents,

I am getting ready to do a bit of mid-winter mold making. Since the steady on folks on this thread are pretty well known to me now I could see building two molds out for the Legend and putting one out to lend among ourselves.

The mold will be a 4 cavity cut on the larger LEE rifle mold block that Titan is now selling.

It could have 2 shorter cavities (located over the pins) and two longer cavities in the middle.

And by shorter cavities, that is everything up to the P Flados Big 'un in length. The two longer cavities could be anything up to a full sized High Ballistic Coefficient (pointy) subsonic. Such a long pointy bullet would be inherently unstable, relatively inaccurate over any longer distances and it would always want to swap ends inside the first 12 inches of meat penetration --- behaving similar to the 30 cal subsonic Blackout cast slug (except being MUCH MUCH bigger, of course).

Actually, it is even possible to cut a sampler mold with 4 different bullets in it (could be different calibers even).

Question for the group: What speed? What weight? What meplat size?

Bullets will all be a powder coat smooth form, so the gas check & grease lube guys need not apply.

I'd vote for one of the cavities being a round nose type subsonic bullet in the 300-350 grain range. From my understanding of ballistics, a spitzer profile bullet has essentially no ballistic advantage at subsonic velocities. So getting the bullet as short as possible for weight is better for stabilization and preserving case capacity.

The other long cavity could be a long pointy secant profile bullet in the 180 grain range with a boat tail for supersonic loading.

[Oldfeller]

I'd vote for one of the cavities being a round nose type subsonic bullet in the 300-350 grain range. From my understanding of ballistics, a spitzer profile bullet has essentially no ballistic advantage at subsonic velocities. So getting the bullet as short as possible for weight is better for stabilization and preserving case capacity.

The other long cavity could be a long pointy secant profile bullet in the 180 grain range with a boat tail for supersonic loading.

I guess that pre-supposes that your subsonic round nose is going to flatten or to upset in some fashion at those very low speeds --- maybe you can tell us more about what you mean so we can understand it a bit better.

The way the current subsonic Blackout works in 30 cal right now is to swap ends (low stability) making a huge swipe cavity while flying sideways in meat due to that minimal ballistic stability.

The Blackout boys LIKE their high BC numbers so they can keep more impact energy after longer and longer subsonic flying distances --- the fact the bullet always swaps ends when it hits meat is just icing on their cake.

Lastly, the construction method of the cavities limits the mold to more traditional flat based bullet shapes, like this one. We also know that the Legend has some magazine resistance build up issues with fat nosed bullets interfering with the magazine nose forms and the AR rifles themselves have some inherent auto-loading "failure to chamber on the way past the splines" type issues with fat bullet noses getting banged up and hanging up on the splines or jamming on the gouge material before seating all the way in the throat.







Here are the gel tests that I based this opinion upon.

[colonelhogan44]

I guess that pre-supposes that your subsonic round nose is going to flatten or to upset in some fashion at those very low speeds --- maybe you can tell us what you mean so we can understand it. The way the current Blackout works in 30 cal right now is to swap ends making a huge swipe cavity due to a lack of stability.

The Blackout boys like their high BC so they can keep more impact energy over more subsonic flying distance --- the fact the bullet always tumbles when it hits meat is just icing on their cake.

Lastly, the construction method of the cavities limits the mold to more traditional flat based bullet shapes, like this one.

What I mean is that ballistic coefficient as published is not linear. For example, a very pointy bullet that has say a high BC of 0.6 at high velocities will have a much lower real BC at subsonic velocities. Subsonic drag is mostly caused by turbulence at the base. See this page: https://www.grc.nasa.gov/www/k-12/airplane/shaped.html.

Supersonic drag is all about controlling/eliminating shockwaves. It's totally different, and as such bullets that are stellar performers at 2500fps might not be optimal at 850. Check out this page for a more bullet specific explanation: http://www.corbins.com/subsonic.htm

[P Flados]

With swaged bullets, the round nose hollow point seems to make sense.

With cast subs, a flat meplat is probably a better choice given that expansion is not likely to be reliable. The loner mold I made had a smaller meplat to help with feeding smoothly in the mag and going into the chamber. The profile behind the meplat was also selected with consideration for allowing rounds to stack right in the double stack p-mags.

A little larger on the meplat and a little more rounded on the ogive should do all of the above and yet allow a little more weight for the same length. However, seating said boolit to Max COAL may not work out due to the short throat unless you include a short nose rider transition from ogive to full diameter shank.

My 200s can probably be reshaped some to make some dummy ammo to work through the choices.

Once you get your nose profile, you make a reamer to match. Then you adjust cut depth to get different weights.

[Oldfeller]

P Flados,

Please don't change your mold, it is just about perfect the way it is.

I can grind multiple versions of a nose form (sequentially, starting with the largest) into a single drill bit about in 4 times as much elapsed time as it takes to post this once I move the bench grinder up to the work room.

Sink a hole to the proposed depth in a block of wood using the depth stop (mocking up the as cast volume) then zero the wooden block's weight then cast hot WW lead into it and you can rough check the bullet's weight before cutting any aluminum.

[P Flados]

I feel the existing molds are OK as is for their purpose.

I was really discussing potential profile changes for you and / or others.

Good luck with the drill grinding. I tried and did not like the results.

FYI, the reamer that I used for the loaner is no longer as it was. I updated it just a little to make a nose punch with a little bigger and sharper meplat. I went out to the shop and could not find it.

Not a big deal, I could fab up a similar one and mail it to you if you want. Material cost would be negligible (W1 drill rod, $7.16 for 3'). I am pretty sure it could be shipped cheap in a padded envelope.

[Oldfeller]

I wrap a piece of cut typewriter paper snugly around the drill bit, about 5-10 layers deep going all the way to the end of the bit and run the drill in reverse while concentrating on getting a light force, nice and smooth slow contour grind. The paper tells me how far back I am grinding on the ogive and what kind of blend I am getting, which is a good thing to know.

As a flute comes back around into the grinding stone the leading "back edge" of the flute catches more grind force than the trailing "front cutting edge", with my fingers and the rolled paper acting like shock absorbers and providing a "bump absorbing suspension" to the intermittent grinding load. The drill bit spiral effect also helps even out the grind force a good bit.

I.E. Using this trick I can grind a small cutting relief into the thing automatically and naturally by just using a good steady elbow resting slow hand grinding technique.

Then I hand stone "side stroke hone" the back 90 degree side of the cutting edge of the nose profile (following the flute contour side) to get rid of the raised burr edge and to get full cutting sharpness on the nose profile using some Gesswein mold maker stones that I have.

I use lots of lube and low cutting force while going back down the existing aluminum hole (just below 9mm hole) that had I pre-drilled, the modified head form is the only cutting depth that the finish bit really has to do. I leave the work holding assembly locked and fixed between pre-drill and finish drill, so I get very minimal bit changeover marks.

I would also like to try raw cutting a hole in a piece of waste stock just to see how well the bit can do it without playing "swap the bit" with the pre-drill, but I suspect not using a pilot hole will mean a larger (somewhat uncontrolled) finished hole.

[Oldfeller]

I added a warning to the info upthread about the rib trimming tooling --- the 5.56 PMAG as trimmed will load a full rack of my 5.56 conversion cases with an appropriately narrow nosed bullet BUT IT WILL NOT LOAD MORE THAN 10 STOCK WINCHESTER 350 LEGEND CASES WITH THE SAME BULLET AT THE SAME OAL WITHOUT BUILDING UP A BINDING ACTION.

This binding issue exists separately apart from bullet nose forms and such, this particular binding is due apparently to the larger diameter head of the stock Winchester Legend case head causing a resistance build up as the doubled-up round stack gets longer and longer.

My recommendation at this stage is to simply WAIT until aluminum or steel 30 round magazines come out built specifically for the 350 Legend.

I have somewhere close to 800 cases that I had converted from 5.56 that will work OK with the converted PMAGs, so my money and effort on the rib trimming tooling aren't totally wasted --- but yours might be if you aren't careful.


============================================


In the future, when this becomes an issue with not enough 5.56 converted cases left, I will develop some sort of sanding apparatus to sand the inside the magazine. This will likely be based upon foam or "sponge" sanding blocks which can be bought on Amazon in fine grits and in smaller thicknesses. Some 3M spray adhesive on a wooden mounting paddle and you can build up the thickness you need in that stackup by picking your material for the paddle.

I might drive the thing off the 3/8" stroke of a variable speed jigsaw or the 1" stroke of a variable speed cutsaw to speed the internal sanding paddle removal rate up some ......

[Oldfeller]

A day for making chips ......





Doing the finishing machining steps






Admiring the stream catching cones and how they flow lead from one to another






Applying a fine finish






And from the chips and sanding dust rises something pretty ......




Functionally, the design of the heavy sprue plate will require no outside clamping force as it swings smoothly (with set screw stabilized "carefully tuned" pin resistance) and it weighs enough to stay flat during casting. As the first sprue jells it applies clamping force to hold the sprue plate down tightly for the next 3 cavities, ditto for each cavity as it jells and the slight contraction pulls down on the plate.

Casting order will be from the pivot pin (left hand) cavity going along the line to the handle (right hand) cavity, with me planning on cutting the sprue with a gloved hand when the puddle last puddle hardens. Bullet ejection from the cavities depends on the smooth bullet form and the use of a wet rag to make a steam cloud on each cast, shrinking the bullets for easy release.

The cavity next to the pin required an offset sprue hole and the cone itself is offset some even to that offset sprue hole, simply to get it all into the limited space that is provided.




..................... all three sprue plates are done and sanded and back in the LEE boxes .......................


Do you think this 4-up mold might jest tend to get a little bit on the warm side while in use ???

[bikerbeans]

I have 2 cavity lee molds that get hot too quick. I can't make myself use the wet rag trick so I just take a break and let the mold cool off. Nice work by the way, I wish I had that talent.

BB

[Oldfeller]

I bought me a 5 pack of 9mm bits, figuring I'd mess up a few of them. I forgot there is lots of extra length that comes with each one, so minor screw ups become "try overs" and nothing gets scrapped.

Yes, I have a form for .200 long nose meplat and a form for a full streamline HBC jobbie. I have a block of scrap gummy aluminum alloy to try the bits out on --- like LEE's special alloy, all soft and gummy. The meplat form cuts gummy aluminum much better than the streamline form, but that minor failure becomes a "try try again" until I can figure out the trick completely ......

[tomme boy]

If you have room, attach a plate of alum on each side of the bottom to pull heat out of the mold.