What cast bullet shape/design for .510 whisper

[Jolyon39]

I am new here and am trying to complete a project rifle. CZ 550 in 416 Rigby converted to 510 Whisper

50 Cal Projectiles are very very expensive here in New Zealand ($7 each) so I am going to learn to cast my own. I am a complete learner but have about 200Lbs of lead lying around.

To run sub sonic I have questions

1. Shape of a bullet for subs. I have seen a lot of bullet shapes from mold suppliers and am guessing that the ribs I see are for lube but what is the right bullet shape for hunting Reds and Japs?
2. Do Gas Checks come off in silencers? This is a silenced only rifle.
3. Weight of bullet. Again there are so many variations
4. What twist rate for a lead bullet? The recommended twist rate for this calibre with FMJ projectiles is about 1:8
5. Can I get Hollow Point lead bullet molds to increase expansion? How do I purify and then create the correct lead mix? My lead is mostly old diving belts and casings for underground wires so it is just "Lead" to me.

[Digital Dan]

Before I start to babble, how far out will you be shooting?

How much pain can you stand?

What are the dimensions of the case?

[Tatume]

Your lead is probably very soft. You might want to add a bit of tin, just to help it flow and fill out your mold. However, at the speeds you propose soft lead will probably shoot well.

You probably do not need a hollow point. Expansion is superfluous with a bullet that big. You might want to add some antimony as well, in case you need to take out a feral cow or some other large, tough animal.

I do not have experience with sound suppressors, but have read that gas checks are a cause for concern for some people. At the speeds you wish gas checks are not needed. Therefore, plain based bullets appear to be the way to go.

Any 50-caliber bullet that is accurate in your rifle should be excellent for hunting kangaroos. However, I suggest that a semi-wadcutter might causing feeding troubles in your magazine rifle. With a bullet that big, I would try to optimize reliability, and depend on diameter for terminal performance.

[Digital Dan]

OK, googled up the cartridge and see what you're playing with....

Lead shielding for electrical cables is pure or close to it, at least on our side of the planet. Your dive weights could be anything and probably are. I never handled a dive weight that wasn't a hard alloy...they ring when dropped on hard surfaces. There is plenty of info here on assessing alloy hardness, do a search.

Bullet shape and weight are your call, but in the subsonic world your most efficient shape is a round nose form like the .22 rimfire. These are some I use for a .30 caliber suppressed rifle to good effect. 183 grains of 30:1 alloy, NO gas check. The GC is unnecessary and you really don't want one to come off the bullet in the suppressor.

http://img.photobucket.com/albums/v298/muddler/Guns/Sneezer/Ducks_zpscqr0rx5a.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Sneezer/Ducks_zpscqr0rx5a.jpg.html)

http://img.photobucket.com/albums/v298/muddler/Guns/Sneezer/LG2_zpshq59nb9c.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Sneezer/LG2_zpshq59nb9c.jpg.html)

You also don't want conventional lube on a suppressed rifle. It will make a mess of the interior of the suppressor. Dry wax, Alox are what you're looking for, or perhaps powder coating. Again, more info on that here available via a search.

Off the cuff I'd say something around 550-600 grains will be a good target weight. Probably 18" twist will do it, but I'd have to have a bullet length to figure that. http://www.geoffrey-kolbe.com/barrel_twist.htm might do the trick for you. As said above, expansion isn't really necessary with a .50, but precision won't hurt.

http://img.photobucket.com/albums/v298/muddler/pig%20pen/DSCN2953_zps5684c330.jpg (http://smg.photobucket.com/user/muddler/media/pig%20pen/DSCN2953_zps5684c330.jpg.html)

Also.... http://www.geoffrey-kolbe.com/drag.htm will help design a bullet if you are inclined.

[dkf]

I don't forsee you needing gas checks with running subsonic. You don't need the possible liability of the gas check hitting a baffle either. If your throat has room you may want to consider a bullet design similar to the Accurate 50-680B in plain base.(if it isn't too light) Accurate can cut practically any design you want so you can modify one of their current designs or come up with your own bullet.

http://www.accuratemolds.com/bullet_detail.php?bullet=50-680B-D.png
http://www.accuratemolds.com/catalog.php?page=15

A .430" metplat is going to be more than enough to put down game and you don't have to worry about expansion. Though you could make soft point bullets for hunting if expansion is desired. Not knowing what BHN your lead is, I can't say if it is too soft. For your application you don't have to have hard lead. You may want to consider Hitek coating or powder coating the bullets instead of lube to keep the suppressor cleaner. I'm no twist rate expert but I'd wager if jacketed is using 1-8 twist barrels then cast will work with the same twist with bullets of similar bearing surface. Though for cast they often do like a little slower twist vs jacketed.

[Tatume]

I have stacks of dive weights and have been an active SCUBA diver for many decades. I have never seen a solid dive weight that was not pure lead.

Some dive weights are bags of shot. I do not know the composition of the shot, having never cut on open.

[Jolyon39]

Thanks for the information, very helpful

To answer your questions:-

Range probably up to 100m (dense bush, not open forest)but once I get used to the drop, maybe 200m
Purpose is hunting Japs and Reds (deer), not Kangaroos
Lead is from 1960's weight belts, cast from scrap my dad found way back then. The rest is from telephone cable work, sealing big joints.


From what you all say, I should do the following:-

Bullet shape - looks like a round head from what you all say (or a small flat head, .430 metplat)
Lube needs to be a Dry wax or powder coat (Will powdercoat negate the need for any lube at all?)
No Gass Check
Bullet weight is about 750 grain to 850 grain according to the write ups on this calibre.
Twist rate for barrel????????


A question:-

Should the base of the bullet be same Diameter be .510 or slightly tapered and therefore smaller than the diameter of the barrel? I would like the base to be smaller so that the column of Gas held behind the bullet is smaller. The problem with silencing 50 cal is that the Diameter of the big bullet carries this extra wide, noisy, column of gas straight through the silencer. This column of gas is the big problem for Silencing 50 cal.

I will do some more searching on here

[Lloyd Smale]

if you plan on killing stuff with it id think seriously on looking at designs for the 500 linebaugh that have flat noses vs round nosed rifle bullets. I agree with the others that in if your shooting subsonic a gas check isn't needed. A good alloy is some of your pure lead mixed 5050 with clip on wheel weight if your looking for hps and expansion.

[Blackwater]

FWIW, most think a pointy nose retains velocity best at all velocities. T'ain't quite so, though. When a bullet goes subsonic, usually at long range, that pointy nose contributes more to INstability, and a rounded nose stays stable better/longer. Below sonic speeds, a boat tail really comes to have significant effect, but also adds to loading problems. I'd likely stick with a flat base for my choice, and take the easier loading and longer bearing surface. Those advantages would be more likely to give the best results, I think?

And the nose shape: Tests with BPCR's tend to indicate that the parabolic "rocket nose cone" type RN's tend to hold up a little better at long range, like the Lyman 458132. However, just as Lloyd points out, the flattened nose produces better impact effect.

So, combining all that, if it were me, I think I'd go with something in the heaviest wt. you can seat in your case without the base extending down too far into the powder chamber, with an OAL that would feed in your gun, and a moderate FP (something like 40-50% of dia.?), and a good, nicely tangent ojive from shank to the flat point. That ought to do workmanlike service, I think, and it'd have no GC for the above stated reasons. No need to go subsonic if you aren't using a suppressor.

Ultimately, though, only way to really tell what works best is to try them. FP's should work best on animals, but when you're shooting a .50, any shape should be a real killer on game. All you really have to do is put them in the right place. A .22 LR in the right place beats even a .50 in the guts, etc. I've long wanted a .50 to play with, just "because," but have never pulled the trigger on that one. Now that Starline makes .50/110 cases, and since that's all I'd ever likely want or be able to take these days, that would probably be my choice, and probably in a #1 or #3 Ruger, rebarreled and restocked. I STILL have a yen for one, even though I'm not as tough as I used to be. I guess it's a "pride of ownership" thing?

[Digital Dan]

The bullet above in my previous post doesn't slow much over distance, this with a 1025 fps MV. Calculated BC is in the ballpark of .390 and shooting between 50 and 100 yards tends to support that.

Range


Drop
Drop
Windage
Windage
Velocity
Mach
Energy
Time
Lead
Lead


(yd)
(in)
(MOA)
(in)
(MOA)
(ft/s)
(none)
(ft•lbs)
(s)
(in)
(MOA)


100
17.6
16.8
1.5
1.4
973.0
0.872
384.6
0.300
0.0
0.0


200
-0.0
-0.0
5.6
2.7
928.5
0.832
350.3
0.616
0.0
0.0


300
-57.9
-18.4
12.3
3.9
890.2
0.797
322.0
0.946
0.0
0.0


400
-159.7
-38.1
21.4
5.1
856.2
0.767
297.8
1.290
0.0
0.0


500
-308.9
-59.0
32.9
6.3
825.2
0.739
276.7
1.648
0.0
0.0


600
-509.3
-81.1
46.7
7.4
796.8
0.714
257.9
2.018
0.0
0.0


700
-764.7
-104.3
62.9
8.6
770.3
0.690
241.0
2.402
0.0
0.0


800
-1079.0
-128.8
81.4
9.7
745.3
0.668
225.7
2.800
0.0
0.0


900
-1456.5
-154.5
102.4
10.9
721.7
0.646
211.6
3.211
0.0
0.0


1000
-1901.6
-181.6
125.9
12.0
699.5
0.627
198.8
3.636
0.0
0.0





325 fps velocity loss at 1,000, less than 100 at 200 yards. The same form in .50 cal would slow less. One might gain some with a spitzer form, but I doubt it would be meaningful. There is a world of difference in aerodynamic theory between subsonic and shazzam.

[M.A.D]

On my 500 HBH case , in lead for plinking i use a 975 grain gas check bullet from Cast Bullet engineering in Australia... Handles 1-9 twist barrel very well.
Castbulletengineering.com.au He charges about $150 and the part number is 512-975GC Single Cavity (http://nz.castbulletengineering.com.au/bullet-moulds/rifle/50-calibre/512-975gc-single-cavity)

[Digital Dan]

Hey MAD, how much that gun weigh you're plinking with?

[MT Chambers]

No matter how many diff. cast bullets I use in my 50/90, long ones, short ones, I always come back to Lyman #515142.

[Digital Dan]

The question posed to M.A.D. was not idle and I think the weight of the Lyman 515142 is perfectly viable for the OP. Reason I asked goes to my experience with BP bullet guns, or slug guns as they are often called. BP muzzle loaders from the old days that still have a following. A case in point:

http://img.photobucket.com/albums/v298/muddler/Guns/Black%20Powder/DSCN3202_zps4dffc135.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Black%20Powder/DSCN3202_zps4dffc135.jpg.html)

It's a .50 caliber that shoots a 850 grain paper patched slug in the velocity range of 1050 fps. It is a stunningly accurate rifle out to several hundreds of yards. It uses 200 grains of BP to make that happen and the gun weighs in the mid to high 20 pound range. It won't make your eyes water when you shoot it, but it is not gentle by any stretch of the imagination. A friend shoots another of .56 caliber which uses either a 900 grain or 1300 grain projectile, depending on mood or objective. 250 grains of BP to get the same approximate velocity. It weighs in the mid 40# range and WILL make your eyes water.

http://img.photobucket.com/albums/v298/muddler/Guns/Black%20Powder/DSCN0187_zps19e3eed3.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Black%20Powder/DSCN0187_zps19e3eed3.jpg.html)

Anyone "plinking" with a .50 cal sporting rifle with "subsonic" bullets in the 900+ grain weight range is tougher than old boot leather. It isn't going to be conducive to a lot of shooting on any particular day, week or month.