510 Whisper Build Advice (Stock/Bottom Metal/Magazines/Twist/Barrel Length)

[45-90]

Instead of outside neck turning each case, could one not machine a dummy chamber and run a precision reamer down the inside of the neck? I bought 400 cases and it's going to be SLOW to turn the OD on each one.

Edit: I could bush the reamer to run concentric w/ the neck in the cartridge holder.

I just tried it in a lathe...it won't chamber...

Cut 338 Lapua case to length leave only a bit extra to final trim length.

Use your sizing die WITHOUT the expander ball and lube;& size.

Made a steel case holder similar to Wilson to hold the case for boring.

Bore case wall to around .013

Put expander ball back in ...use some Lee resizing lube on the inside of the case and expander ball, pump it into the FL die with the die all the way down, redo the bottoming out on the shell holder a couple of times.

But it still does Not fit my gauge or the rifles chamber.

Here's why...the die doesn't have the sharp 7 degree shoulder needed. The die is made to neck turn the shoulder.

I could make this work by making a die in the lathe to push the shoulder back at the correct angle since its so close...but pushing sharp shoulders it not friendly to brass cases...they'd rather collapse and buckle rather than move, especially anything sharper than 30°.

Since I have a lathe it's easier for me to neck turn ( about 15 seconds in and out) and work with the factory die as originally designed rather than doing these extra steps.
The runout was within .001" on this sample, and is always good with a snug fitting mandrel and a lathe.

So that's why they are neck turned...but this way is very close and only a tiny bit of neck turnig would be needed to get this to fit the gauge and the gun.

Use any part of this procedure if it will make your case making easier...

I could make the final die but this way takes more time, right now...and I'm not in the die business for others, and have other projects I'm working on.
It's just another way, that will work, if I make the final die.
Might do it later just for fun...but that doesn’t serve anyone but me. And I have all the 510 whisper cases I need.
It's a fun caliber with many power levels, too bad the industry who created it doesn't support it better. Starline could easily produce cases for it...

 

[45-90]

So I went out and did it.
Built a double die, cause it needs a sharp shoulder to finish up the last tiny bit.

First die hornady die, 2nd die home made with a sharper shoulder. Then the other side of that die or 3 rd die to shave the sharp shoulder...it leaves metal shavings in the die so it needs cleaned and the case od deburred.
It finally fits the rifle chamber and a primer inserted to test fire the case.

So it can be done, but it takes longer then neck turning in a lathe.
But its only the final 1/16" that needs to be neck turned as you can see on the photos where it won't completely enter the gauge, when you ream or bore the neck ID for thickness first.
The last die with the sharp edge takes care of that 1/16".

So it's possible if ya want to try something different, but the whole idea was to neck turn and use the FL die to set the headspace.

 

[rosey]

I had the same thought about forming the shoulder and cutting the ID, good to know it's most likely going to be even more trouble.

I'm just starting this journey. Don't even have a rifle yet but plan to get an MRAD barrel made soon. I'm not a machinist so I'm still trying to dial in the neck turning process. Couple questions if you don't mind...

A regular 50 cal mandrel was a no go, at least with my brass. I was going to make a mandrel that's tight on my brass (~.520") in the neck area and tapers down so it can bottom out on the bottom of the charge cavity for consistent positioning. Is this what you do?

Do you grind a tool to hit the shoulder angle? I was thinking about trying a 43 degree KM cutter and just finishing it with the die.

I'm trying to do these at least a few hundred at a crack on a manual lathe, is there a trick to getting parts in and out of the lathe quickly? With a mandrel in the chuck and a center in the tail stock its pretty time consuming to move the tail stock out of the way and yank the tightly fit work piece off the mandrel.

I made a quick sketch of the case off the PTG reamer, not completely sure on the specs but I couldn't find anything and wanted something to go off of.

 

[45-90]

On the shoulder angle you'll have to check your reamer...I grind the tool at 41.5° but the reamer was 83° as it came from PT&G and so is the drawing I saw.

It appears the shoulder angle has been changed a few times.
Mine is only 7° off perpendicular or 83° off centerline.

I did a bunch at 41.5° and held short and let the die finish the last few thousandths.
The height is so short of you make the angle a bit off and hold off a few thousandths and let the finish die do the shoulder.
I ran the shaving die at 7° off perpendicular....its not square across the face...but 7°.

This is the lathe setup. Mandrel turned to fit ID of the brass in question.

I mill all the brass to length in a Bridgeport mill and collet closing fixture... only takes one or two seconds cut down from 338 Lapua...fast and clean.

I do not use the 3 way cutter heads like Henderson are a piece of crap for jobs like this slow and inefficient.
I tried them, $120 wasted on two inefficient cutter heads...
Way faster to do the deburring operations separately.
The 6 fluted end mill does an excellent job when cutting long lengths of brass down to finish length, it just cuts off 1/4" or 1/2" of brass in 2 seconds.

Do not turn off the spindle, load and unload while running, spin tailstock handwheel in and out with live center installed. This is easy for me been a machinist for 35 yrs...I go to indicator zero mounted on the lathe.
Should be able to do 200 to 300 per hr.

After trying both methods neck turning is the best way ...faster more precise and how the cartridge was designed.
Plus no one is making dies for OD finishing but me...your FL die won't work unless you neck turn to finished the shoulder, then ya have to ream or bore ID....and I ain't gonna make dies for others in my spare time.
I did the 510 Whisper brass on an industrial scale...1000 finished and annealed pieces.

 

[smdub]

45-90, thanks for the great pics (as always.)

Well, it looks like someone has thought of this before. Was on the CH4D site and they sell a reamer die for 510W. I need to call them anyway so will ask for details about that.

https://www.chtoolanddie.com/calibers/510Whi

 

[smdub]

What is the neck size on finished/loaded brass? Per wikipedia (not the most tusted source but since there is no SAAMI spec...) the neck is 0.549". Bullets measure 0.510. My brass is 0.015" at the unsized neck. So thats 0.540. No neck turning would be needed? Something doesn't add up... Ok, they list base AND shoulder diam both as 0.587". Lapua has a bit of taper to it so I know the shoulder will be smaller than that. Ok, the wiki numbers are wrong then.

 

[45-90]

.mm..mm.m.....++

What is the neck size on finished/loaded brass? Per wikipedia (not the most tusted source but since there is no SAAMI spec...) the neck is 0.549". Bullets measure 0.510. My brass is 0.015" at the unsized neck. So thats 0.540. No neck turning would be needed? Something doesn't add up... Ok, they list base AND shoulder diam both as 0.587". Lapua has a bit of taper to it so I know the shoulder will be smaller than that. Ok, the wiki numbers are wrong then.

First neck turning is a must...if you do not understand that, you do not understand the concept of the cartridge.

This cartridge headspaces off the shoulder you cut into the case!
What are you gonna headspace off of?

It does not headspace off the case mouth like a 9mm.
The cartridge, dies, and reamers are not designed that way.

My neck size is .537" plus or minus .001".
All the fired brass is .538" on the neck even with heavy loads like 300 gr at 2875 fps or 750 Atips at 1500 fps.
Brass usually springs back a thou or two for easy extraction.
Two at .540" will not fit the gauge...as shown in pic...the 650 gr military "pulled bullets" must be sized in a .5095" dia die because they spring back .0005", to get the pull marks which can be .012" high, down to .510".

These pull marks (pic)will interfere with chambering as it will slightly bulge the brass case neck.

 

[smdub]

My neck size is .537" plus or minus .001".

I understand everything you said and how the cartridge works. Absent a SAAMI spec the wikipedia numbers were all I had to go in. Adding up the bullet diam and the brass thickness didn't add up . Your 0.537" makes sense. The wiki 0.549 is an impossible number as its BIGGER than the bullet + unturned brass neck - which would be impossible to headspace. I don't have a cartridge or reamer in front of me yet but I knew something was off.

I already have a bullet swager as I've been buying as many M33 pulls as I can afford/store for the 50BMG guns. One of the big reasons I'm interested in 510 Whisper. I have the bullets. I have a VERS50 suppressor. I have the slow powders. I love 300BLK subs. I just need the big gun!

 

[45-90]

I wish Starline would make 510 Whisper brass...there is quite a bit of interest in with sub shooting becoming more popular these days. And SSK does not really support the .510 they are always out of brass and dies, and just 10 pcs their brass would get ya started and give you the dimensions needed to make your own...
But that's not how it is.
I can make it fairly easy, but I have the machine tools to do so, most do not... so even it I duscuss, or show the machining in action it helps only a few.

Drawings found in the internet are not always accurate.

I shoot the 300 blk, 8.6 blk, 338 Spectre, 338 ARC, 450 bushmaster fast twist for 500 gr subs, & Newly built 375 Raptor ...and of coarse the 510 whisper.
The 510 can be the most fun because it has a whole host of bullets from 300 gr to 1002 gr available.
I run the supersonic 300 gr Barnes at 2875 fps, for max energy more energy than some elephant guns... or military APIT popping off at sub speeds louder than the initial muzzle report...
Subsonic APIT impact with plywood or light metal post set them off...would it go off if ya hit a hog shoulder bone? Probably...cook a portion of the ham?

Subsonic APIT at 1100 fps and slower do not harm your AR 500 plate above 1200 fps damage occurs. Around 1400 to 1500 it starts to penetrate 3/8" AR 500 armor plate.
Today ...I recieved some new 700 gr AP to try...

I tried these powders with the military M33 hard ball 647 gr in 510 whisper...one can use just about any powder ...some powders are much better than others ...you have to adjust charge for your barrel, as some are above sub speed. So ya bring em down in velocity making sure they exit the barrel before firing the next round.
The 510 Whisper is a very fun sub caliber.