Anybody Cast for 458 Socom
- Thread starter Gary
- Start date
http://www.artfulbullet.com/index.php?threads/458-socom-anyone.2255/
Ian is the man to talk to about this.
Ian is the man to talk to about this.
Ian
Notorious member
Whoa, Gary, back up. First, we need a LOT more data than "458 Socom" to even hazard a guess beyond confirming that "yeah, you can shoot cast in those". Second, the place to start with reloading for one isn't with load data, it's with getting the tools needed squared away and figuring out how the chamber is cut.
Having bona-fide Tromix or Teppo Jutsu parts and a Sheridan case gauge to start off with will solve 90% of the headaches associated with the caliber.
Having bona-fide Tromix or Teppo Jutsu parts and a Sheridan case gauge to start off with will solve 90% of the headaches associated with the caliber.
Gary
SE Kansas
Thanks Ian; what my grandson did was buy an assembled upper last month. He hasn't brought it by yet but he knows I want to find out the particulars. I do know that the barrel is a 16" barrel (don't know the maker). I want to slug it and come up with a mould. Probably looking at a 450 - 500gr bullet. I'll keep you posted. BTW, enjoyed your write up.
Ian
Notorious member
Ok, so it's an AR-15.
This is not a SAAMI-recognized cartridge, and correct chamber specs are very much kept private by the inventors. If the chamber was cut by anyone other than the two I mentioned, the reamer was reverse-engineered and it's a pig in a poke regarding headspace, shoulder placement, case body taper, neck diameter, throat angle/length, and bore diameter, so a chamber/throat cast will help a lot. There is pretty much zero room for error to make cartridges that function and shoot straight, since neck clearance is so tight and the AR-15's action must labor very hard to poke one of those massive cartridges into the chamber and lock into battery. The difference between .4580" and .4585" sizing on the driving bands meant the difference between keyholing patterns and ragged hole groups. The difference between .4520" and .4515" bullet noses meant either it would feed on its own or I could not force a round to chamber even with the forward assist. .4590" bullets made a slight interference fit between cartridge neck and chamber neck, which could be a dangerous situation with no room for the neck to expand to release the bullet.
Lancer magazines are your friend with the Socom. Others will work, but trust me, buy some Lancers. Pmags are no good with heavy bullets due to the rib on the front wall. If he's planning on using a suppressor, he will benefit from learning how to powder coat his cast bullets.
Watch all of Full.Lead.Taco's u-toob vids (start with the one he linked in my other thread), he gives a great overview of how he's doing things, but keep in mind he has the correct barrel, bolt, and chamber gauge to make all his fitment testing super-easy.
This is not a SAAMI-recognized cartridge, and correct chamber specs are very much kept private by the inventors. If the chamber was cut by anyone other than the two I mentioned, the reamer was reverse-engineered and it's a pig in a poke regarding headspace, shoulder placement, case body taper, neck diameter, throat angle/length, and bore diameter, so a chamber/throat cast will help a lot. There is pretty much zero room for error to make cartridges that function and shoot straight, since neck clearance is so tight and the AR-15's action must labor very hard to poke one of those massive cartridges into the chamber and lock into battery. The difference between .4580" and .4585" sizing on the driving bands meant the difference between keyholing patterns and ragged hole groups. The difference between .4520" and .4515" bullet noses meant either it would feed on its own or I could not force a round to chamber even with the forward assist. .4590" bullets made a slight interference fit between cartridge neck and chamber neck, which could be a dangerous situation with no room for the neck to expand to release the bullet.
Lancer magazines are your friend with the Socom. Others will work, but trust me, buy some Lancers. Pmags are no good with heavy bullets due to the rib on the front wall. If he's planning on using a suppressor, he will benefit from learning how to powder coat his cast bullets.
Watch all of Full.Lead.Taco's u-toob vids (start with the one he linked in my other thread), he gives a great overview of how he's doing things, but keep in mind he has the correct barrel, bolt, and chamber gauge to make all his fitment testing super-easy.
Ian
Notorious member
Since it's a Tromix upper (good call, by the way, guaranteed to be on-spec and match the chamber gauge which you will absolutely LOVE), the Lee 340, 400, and 500 RFN moulds will all fit, but you might have to lap them or powder coat them to make them a full .4585" and for subsonics in a carbine I'd suggest sticking with the heaviest bullet you can get. If you powder coat, check out that bullet FLT designed, it's an NOE and he's having really good luck with it in his rifle.
The problem with a lot of 45/70 bullets is when they get up around 450 grains, the noses are too long for the Socom. The 45/70 single-shot rifles don't have an OAL restriction, but do have a black powder capacity limitation, so with heavy bullets, traditionally the extra metal is put on the nose end rather than crowd powder space. For example, the Lyman 535 Postell and 505 hemispherical nose bullets will not work well in the socom because the front driving band will be halfway down in the neck.
Using GI or Lancer magazines, the bullet can stick out of the case an absolute maximum .690". The Lee 500 RF gas check bullet must be seated just a tiny bit deeper than will crimp in the crimp groove, just about .015" or so, and at that depth the front driving band is just about to "kiss" the throat leade.
OK, for the loading, you're probably going to be stuck using Reloder 7 for subsonics, since that barrel will have a carbine-length gas system. Walk that line between reliable cycling and cracking the sound barrier. Hopefully a faster powder will work, but pressure drops off fast and velocity also builds very quickly in a 16" barrel. You'll just have to play with it and find out.
You'll need a neck expanding die, a real one, not just a belling die. Unless your bullets are over 15 bhn, you're going to have trouble with the Lee expander not making the neck large enough to prevent the bullet being swaged. It's perfect for jax though. I made a custom spud for mine (I forget the size at the moment), just for softer cast bullets.
Some people cuss the Lee dies and everyone seems to recommend Hornady, but my Lee set works fine. Full cam-over makes the brass .001 below flush of the case gauge, right where Tony wants it. Don't use too much crimp, just barely turn the mouth past straight. Do chamfer your new brass on the inside before loading the first time. Check EVERY cartridge in the gauge before trying to shoot it. Don't drop a round in the chamber and slam the bolt home on it, the thin pistol primers can slam-fire, and DO NOT use Federal primers, they are too sensitive. Get a Caldwell rail-mount brass catcher if you don't already have one, brass disappears and you'll cry a lot.
When re-sizing fired brass, check headspace. Fired brass likely will likely stick out of the case gauge .020" or more, don't be alarmed, it extracts under pressure and the shoulder can move forward a lot and that doesn't mean the headspace is excessive. Probably less of a factor in a carbine system than my pistol system, though. Brass will shorten ten thousandths after firing, and probably stay short when resized, so watch your crimp die settings very closely. For this reason, the Lee factory crimp die is highly recommended, you can use it to remove the mouth flare after seating and there's a good bit of length tolerance there so you aren't having to constantly re-adjust your seating die to deal with the moving target of case length.
I'm dumping all this info on you because I'm taking a vacation for a couple weeks starting tomorrow and am not sure I'll have good internet where I'm going. Should have, but who knows.
The problem with a lot of 45/70 bullets is when they get up around 450 grains, the noses are too long for the Socom. The 45/70 single-shot rifles don't have an OAL restriction, but do have a black powder capacity limitation, so with heavy bullets, traditionally the extra metal is put on the nose end rather than crowd powder space. For example, the Lyman 535 Postell and 505 hemispherical nose bullets will not work well in the socom because the front driving band will be halfway down in the neck.
Using GI or Lancer magazines, the bullet can stick out of the case an absolute maximum .690". The Lee 500 RF gas check bullet must be seated just a tiny bit deeper than will crimp in the crimp groove, just about .015" or so, and at that depth the front driving band is just about to "kiss" the throat leade.
OK, for the loading, you're probably going to be stuck using Reloder 7 for subsonics, since that barrel will have a carbine-length gas system. Walk that line between reliable cycling and cracking the sound barrier. Hopefully a faster powder will work, but pressure drops off fast and velocity also builds very quickly in a 16" barrel. You'll just have to play with it and find out.
You'll need a neck expanding die, a real one, not just a belling die. Unless your bullets are over 15 bhn, you're going to have trouble with the Lee expander not making the neck large enough to prevent the bullet being swaged. It's perfect for jax though. I made a custom spud for mine (I forget the size at the moment), just for softer cast bullets.
Some people cuss the Lee dies and everyone seems to recommend Hornady, but my Lee set works fine. Full cam-over makes the brass .001 below flush of the case gauge, right where Tony wants it. Don't use too much crimp, just barely turn the mouth past straight. Do chamfer your new brass on the inside before loading the first time. Check EVERY cartridge in the gauge before trying to shoot it. Don't drop a round in the chamber and slam the bolt home on it, the thin pistol primers can slam-fire, and DO NOT use Federal primers, they are too sensitive. Get a Caldwell rail-mount brass catcher if you don't already have one, brass disappears and you'll cry a lot.
When re-sizing fired brass, check headspace. Fired brass likely will likely stick out of the case gauge .020" or more, don't be alarmed, it extracts under pressure and the shoulder can move forward a lot and that doesn't mean the headspace is excessive. Probably less of a factor in a carbine system than my pistol system, though. Brass will shorten ten thousandths after firing, and probably stay short when resized, so watch your crimp die settings very closely. For this reason, the Lee factory crimp die is highly recommended, you can use it to remove the mouth flare after seating and there's a good bit of length tolerance there so you aren't having to constantly re-adjust your seating die to deal with the moving target of case length.
I'm dumping all this info on you because I'm taking a vacation for a couple weeks starting tomorrow and am not sure I'll have good internet where I'm going. Should have, but who knows.
Gary
SE Kansas
I'm a fan of NOE equipment and have several expander plug that slips into a Lee expander die and has worked for my 44/40 and 357's; so I'll get an expander from NOE and probably a set of Hornady Precision Dies and also a Lee FCD. I presently have 10 or 15 different powders, soon to have 16 with the addition of Reloader 7. Thanks again for all your help. Have a great vacation.
BTW, I PC everything I cast.
Gary
BTW, I PC everything I cast.
Gary
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Ian
Notorious member
Thanks!
See if you can get your hands on one of those NOE moulds that Full Lead Taco has, I haven't checked NOE's site but they might have one left. Failing that, I'm pretty happy with the Lee 500 RF gas check mould, without the check. They're just right for casting with clip-on WW with little to no extra tin and then powder coating them, they come out just small enough that way that there's room for the PC and you shouldn't have to size the nose for them to chamber. Run them through a .458" sizing die and they come out around .4584 or so, which is pretty near perfect. With these huge pills I found that if I didn't bake them for 25-30 minutes the PC didn't fully cure, it takes a long time to soak the bullets to full temperature before the cure time begins.
See if you can get your hands on one of those NOE moulds that Full Lead Taco has, I haven't checked NOE's site but they might have one left. Failing that, I'm pretty happy with the Lee 500 RF gas check mould, without the check. They're just right for casting with clip-on WW with little to no extra tin and then powder coating them, they come out just small enough that way that there's room for the PC and you shouldn't have to size the nose for them to chamber. Run them through a .458" sizing die and they come out around .4584 or so, which is pretty near perfect. With these huge pills I found that if I didn't bake them for 25-30 minutes the PC didn't fully cure, it takes a long time to soak the bullets to full temperature before the cure time begins.
Full.lead.taco
Active Member
a quick +1 to Ian's recommendation to get one of those Tromix slotted case gauges. Those will help immensely in the loading and troubleshooting process. As far as molds for the 458 socom, the NOE HTC 459-500-SP mold was designed specifically for the 458 socom for some 500 gr powder coated subsonic shooting. It also doubles as a single shot 45-70 bullet. I think this mold is the fastest pot drainer that I have. I picked up two of those in a 5 cavity configuration to help speed up my production. Running two of those at the same time drains the pot fast! I've shot a bunch of these, and it is sure fun to lob them out a ways. And if you have any questions (that I can answer) I'd love to help!
Ian
Notorious member
Find out how your system is going to work with 500+ grain bullets before going lighter. The powder needs a lot of mass to work against to make the 5,000-ish PSI minimum port pressure in a carbine-length system and yet not push the bullet supersonic.
Powders in the Herco to 2400 burn range drop off pressure pretty fast by seven inches of bullet travel, so you might need something as slow-burning as Reloder 7 to keep operational pressures up at the port, but that's a double-edged sword with the Socom because fast rifle powders only will burn about 60-70% in a 16" barrel, so they're still making pressure at the muzzle and thus adding velocity to the bullet. Trying to balance port pressure that will cycle the action yet stay sub-sonic can be a little tricky, and something you should be aware of as you try different loads. I doubt you could make the rifle work and keep a 300-grain bullet subsonic with carbine gas system. Pistol system wouldn't be a problem with a 300-grain bullet, just use something like Unique....but as far as I'm aware all the Tromix 16" barrels have a carbine-length gas system that is more oriented toward full-power ammo with lighter bullets than it is for heavy subsonics.
Powders in the Herco to 2400 burn range drop off pressure pretty fast by seven inches of bullet travel, so you might need something as slow-burning as Reloder 7 to keep operational pressures up at the port, but that's a double-edged sword with the Socom because fast rifle powders only will burn about 60-70% in a 16" barrel, so they're still making pressure at the muzzle and thus adding velocity to the bullet. Trying to balance port pressure that will cycle the action yet stay sub-sonic can be a little tricky, and something you should be aware of as you try different loads. I doubt you could make the rifle work and keep a 300-grain bullet subsonic with carbine gas system. Pistol system wouldn't be a problem with a 300-grain bullet, just use something like Unique....but as far as I'm aware all the Tromix 16" barrels have a carbine-length gas system that is more oriented toward full-power ammo with lighter bullets than it is for heavy subsonics.
Ian
Notorious member
I tried Trail Boss in a few things long ago, found very little use for it. Let me show you something that I think you're missing here about AR-15s and gas port pressure.
Here is a QuickLoad prediction for Trail Boss and the Lee C457-500F, using all the actual parameters from my cartridges and bullets that fit my gun:
What you should pay particular attention to is the graph at lower left, and the chamber pressure indication of 2317 psi, which is what the pressure is predicted to be at the point that seven inches (approximate gas port location) of bullet travel crosses the pressure curve. You need about 5-8000 psi to operate the bolt of a DI AR-15, depending on gas port diameter and bore diameter. What this means is a fast-burning powder like Trail Boss won't work the action. Also, with a 500-grain bullet seated to fit the AR-15 magazine, a case full of Trail Boss will only generate around 900 fps from a 16" barrel, unsuppressed. Actually it will be less due to gas port losses, probably about 860 fps or so. It won't cycle, but it will be quiet, clean, and slow due to (respectively) 1023 psi muzzle pressure, 100% powder burn early in the cycle, and pressure dropping off very quickly due to large expansion ration and fast-burning powder.
Now, let's look at something that WILL cycle your AR:
Note here, with Reloder 7, that you can get just over 5000 psi of port pressure and stay subsonic. If this in fact turns out in real life as predicted here, the action should cycle reliably with standard M4 parts or even a full-auto BCG with no issues. The drawbacks are relatively high muzzle pressure (= noise and more to suppress if you use a silencer), and the 81% burn rate, which means powder kernel mummies accumulating in the action, FCG, and magazines. I can tell you from experience that Reloder 7 is very consistent at low pressure and will work well, but will eventually foul the works, so plan on frequent cleanings. Same for any other powder that won't burn completely. But it will WORK and it will stay SUBSONIC.
See what I mean about pressure curves of fast and slow powders? Now I ran the numbers with Alliant 2400 and Hodgdon Lil'Gun and both look like they might work. Actually, Lil'Gun looks to be about like Reloder 7 but burns much better. Alliant 2400 looks like it might be about the fastest-burning powder you can use with a 500-grain bullet in your system and still be subsonic. Keep in mind predictions are notoriously off with QL and the Socom, and I've already been bitten by a serious mis-prediction with Hodgdon Longshot, though Herco and HS-6 were spot on for me. You'll just have to try some some loads and see what happens, always using a chronograph and always erring very far on the side of caution with starting loads until you know how your powder and bullet, will react in your rifle. HTH.
Here is a QuickLoad prediction for Trail Boss and the Lee C457-500F, using all the actual parameters from my cartridges and bullets that fit my gun:
What you should pay particular attention to is the graph at lower left, and the chamber pressure indication of 2317 psi, which is what the pressure is predicted to be at the point that seven inches (approximate gas port location) of bullet travel crosses the pressure curve. You need about 5-8000 psi to operate the bolt of a DI AR-15, depending on gas port diameter and bore diameter. What this means is a fast-burning powder like Trail Boss won't work the action. Also, with a 500-grain bullet seated to fit the AR-15 magazine, a case full of Trail Boss will only generate around 900 fps from a 16" barrel, unsuppressed. Actually it will be less due to gas port losses, probably about 860 fps or so. It won't cycle, but it will be quiet, clean, and slow due to (respectively) 1023 psi muzzle pressure, 100% powder burn early in the cycle, and pressure dropping off very quickly due to large expansion ration and fast-burning powder.
Now, let's look at something that WILL cycle your AR:
Note here, with Reloder 7, that you can get just over 5000 psi of port pressure and stay subsonic. If this in fact turns out in real life as predicted here, the action should cycle reliably with standard M4 parts or even a full-auto BCG with no issues. The drawbacks are relatively high muzzle pressure (= noise and more to suppress if you use a silencer), and the 81% burn rate, which means powder kernel mummies accumulating in the action, FCG, and magazines. I can tell you from experience that Reloder 7 is very consistent at low pressure and will work well, but will eventually foul the works, so plan on frequent cleanings. Same for any other powder that won't burn completely. But it will WORK and it will stay SUBSONIC.
See what I mean about pressure curves of fast and slow powders? Now I ran the numbers with Alliant 2400 and Hodgdon Lil'Gun and both look like they might work. Actually, Lil'Gun looks to be about like Reloder 7 but burns much better. Alliant 2400 looks like it might be about the fastest-burning powder you can use with a 500-grain bullet in your system and still be subsonic. Keep in mind predictions are notoriously off with QL and the Socom, and I've already been bitten by a serious mis-prediction with Hodgdon Longshot, though Herco and HS-6 were spot on for me. You'll just have to try some some loads and see what happens, always using a chronograph and always erring very far on the side of caution with starting loads until you know how your powder and bullet, will react in your rifle. HTH.
Full.lead.taco
Active Member
Trailboss is too fast for a semi-auto. It does work great in bolt guns and single shots as a subsonic powder, but like Ian says, you won't have a high enough gas port pressure to cycle. I've had good luck with imr4198 powder with the heavy subs, but still need to try some hs-6 loads. A5744 cycled nicely and shot well, but was too dirty, especially with the suppressor.