.458 SOCOM experiences and results with cast

[the_ursus]

Since 458 SOCOM load data is hard to find and A.R. 15 style rifle’s are new to me I thought I would start a thread to get some discussion going on this subject. I hope to compare notes with a few of you guys and possibly spread more information about cast bullets and the 458 socom. I knew from the start that I couldn’t afford to shoot factory ammo through this rifle so reloading was the answer, particularly cast bullets.
I am shooting a Tromix 16” upper assembly purchased complete from the company. Palmetto lower receiver and hyper fire sharpshooter trigger.
I cast up some bullets with the 458 300 grain flat nose from RCBS. My Alloy is 75% wheel weight and 25% range scrap water quenched. Everything has been sized to .459 with White label lube 50-50 beeswax.
Powder of choice is Reloader 7 since I have a few pounds and seemed like it fits the bill with CCI 300 primers.
My questions to start off with are as follows:
Has anyone had problems with fouling in the gas tube from lubed bullets?
Since chamber pressure is around 35,000 PSI how do I look for pressure signs on the primer rated for much higher than that? From what I understand by the time you see pressure signs on a pistol primer you have exceeded the working pressure of an AR.

[boman250]

I have used both a 330g and a 285g cast bullet in mine. Mixed results. I most definitely needed a gas check in both cases as the accuracy without them was abysmal.

I have only used H110 and H4198 I think with good results. I have also swaged 45 ACP cases into bullets and those were very good. I will be doing more of that soon as well.

Pressure has not been an issue as I have not pushed it, but I have heard people going as high as 38g of H110 with 300 grain bullets. Not for me. That is crazy.

[the_ursus]

My bullets cast at 335gr with gas check and lube, I’ll post pics of my results tomorrow and maybe get some discussion on that matter as well.

[the_ursus]

Took the rifle back to the range for more testing. 40 grains Reloader 7 yielded 4 shots all touching, about 3/4” group maybe less. I’m beginning to really love this rifle!

[roharmon]

I started shooting 500 grain cast bullets from the Lee mold, which is a blast. The only target so far is a 10” Locust tree which the bullets go straight through with 24.4 grains of IRM at 50 meters.

[the_ursus]

Would that be IMR 4198? I’m thinking about a heavy slow moving bullet for my next load, possibly a Lee 500gr.

[ewlyon]

I have just started loading 458, haven't even tested my loads for accuracy yet, just worked up a load for pressure and function with the NOE 500gr from a Tromix 10.5in upper. Regarding pressure I was mostly looking for breechface impressions and strange ejection, and although I wasn't waiting for the primers to flatten I did look at them for difference from the low level loads. At the top end of my testing I did see very slight cratering but that was well above the charge needed to cycle the gun. Regarding the lube fouling I can't be any help since I coat my bullets

[roharmon]

Sorry, yes IMR 4198. I didn’t think I would like the Lee bullet, but it is fun to shoot. We have moved to KY and I hope to starting shooting it at 100 yards soon.

[the_ursus]

Well, I havn’t seen any impressions on my primers from the bolt and cases seem to eject just fine, I think I’m still in the safe zone. After about 100 rounds I havnt noticed any crud building up from lube, yet.

[pmer]

http://accuratemolds.com/bullet_detail.php?bullet=46-305S-D.png

I shake and baked a few hundred of this boolit. They weigh about 315 grains coated. I'm having trouble getting it to shoot as accurate as want though, the best I can get is about 3'' at 80 paces. 5 will be about 1.25" but flyers mess it up each time. It likes 40 grains IMR 4198 or 11 grains of Unique. The Unique wont cycle the AR but it does better than the 3" 4198 load. I've tried Lil gun, 300 MP, 2400, 296 and 5744 but these weren't too good on target.

My rifle has a A2 stock and I filled the cleaning kit area with coated .224 boolits. The rifle stands vertical by itself and weighs 9.5lbs now and it's a lot easier to shoot full power loads.

It does real good with other projectiles but I'm hoping to use the 46-305s for 150 yard plus deer hunting. This is my first smooth sided mold and I'm learning as I go. The bore is .4595, the mold drops at .458 they grew to .459 and approximate Lyman #2 in hardness. With the coating I've been shooting them at .461 I have the Sage groveless checks and they do help on the higher end. I've read you don't need gas checks up to 1900 FPS with coatings but in this case the bore is cleaner and the groups are better. I chamfered the mouth of my H&I sizing die and use a little sizing wax to install them. On the next batch I think I'll try spraying the boolits and see if that helps.

This is a neat cartridge, 405 grain boolits going 1620 FPS with Lilgun :p

[the_ursus]

233666
335gr (3:1 WW to range scrap water quenched) 40gr Reloader 7 50yds CCI 300 LP primers
4 shot group. Going to creep up the charge and may start working at 100yds.

[JZdryfly]

I've shot hundreds of NEI 458-333 that average 338 grains with #2 alloy and have had no problem with lube residue fouling my gas tube. Favorite loads are 29.5 gr 296, 38 gr 1680, 26.5 gr LilGun, 41.0 gr ReL 7. The NEI is a gas check bullet. I also shoot the plain base Lyman 457658 480 gr bullet with 24.0 gr of I4198 with excellent results and no leading or fouling. All my shooting is at gongs or steel silhouettes, as can be seen on Bang and Clang Alaska

[sqlbullet]

After my panic with my Garand and plain base powder coat, I am sticking with gas checks in gas guns.

I thought I would save some money and powder coat some Lee 200 grain bullets and load them up with BobS' load. They shot fine, but about the third en-block I started to have cycling issues. It ended up being lead fouling in the gas cylinder, but initially presented like a bent op-rod.

YMMV, but that scare was enough to make gas checks seem cheap to me.

[gnostic]

'I understand by the time you see pressure signs on a pistol primer you have exceeded the working pressure of an AR.'

I'd think pistol primers would fail way below the AR's 55k or the 35k PSI working pressure you're loading too. I've always used magnum pistol primers for 35k PSI magnum handloads. I would think a standard pistol primer would blow out before 35k PSI.

[P Flados]

gnostic,

I think the 55k pressure limit for the AR15 platform is for rounds based on the 223/5.56 case. The 458 has a much bigger diameter case and the pressure limit was reduced based on gun stress limits.

I am pretty sure few if any pistol primers fail at 35K. For example, the 327 is rated for 45K and does not specify rifle primers.

Good load data is needed for any gun with a 35K limit. Looking at brass or primers is not going to detect exceeding 35K nor is "sticky" extraction a useful tool.

I actually wish someone would market "pressure indicating primers" with specific features useful for judging lower pressure. However, such a product would never make past the company lawyers since misuse and/or misunderstandings would be likely as would the resultant lawsuits.

[nun2kute]

Excellent thread. I was shooting a Accurate mold that came out to 472g with PC and GC. The only part I remember was 1 inch groups at 100 yard. Alas, my laptop crashed and took everything with it. It's such a FUN gun to shoot, I won't mind doing it again, soon as I get my current project finished. Tromix (or is it Teppo Jutsu ?) has a bunch of good data on it too.

[gnostic]

gnostic,

I think the 55k pressure limit for the AR15 platform is for rounds based on the 223/5.56 case. The 458 has a much bigger diameter case and the pressure limit was reduced based on gun stress limits.

I am pretty sure few if any pistol primers fail at 35K. For example, the 327 is rated for 45K and does not specify rifle primers.

Good load data is needed for any gun with a 35K limit. Looking at brass or primers is not going to detect exceeding 35K nor is "sticky" extraction a useful tool.

I actually wish someone would market "pressure indicating primers" with specific features useful for judging lower pressure. However, such a product would never make past the company lawyers since misuse and/or misunderstandings would be likely as would the resultant lawsuits.

You might be right about the AR, the 458 Socom and the lowered PSI, but I don't think it would affect the primer. It would definitely effect the force blowing back the bolt. I can't imagine how a AR lower puts up with the increased recoil, but apparently it will... I don't know where a pistol primer would let go, but I sure wouldn't want to find out. I once pierced a rifle primer and I had to beat the Model 70 bolt open with my shoe. For magnum handgun handloads I use magnum pistol primers, it's my understanding they're harder and less likely to blow out. Also, 296/H110 and 2400 light up better with magnum primers.

[dkf]

The 35k psi limit was put in place due to the bolt thrust limitations of the AR15 platform. going over some is not going to hurt anything but best to keep it under 40k psi at all possible in an AR15. In a bolt gun or similar solid action you can ream for large rifle primers and bump the pressure up considerably.

All I use are CCI 350s for .458socom. You can read the primers somewhat with experience but it is just approximate. Once you start seeing ejector and extractor printing on the headstamp you are over 40k psi by a sizeable amount.

[pmer]

Something I learned about the SOCOM is my kinetic bullet puller can't grip the rim because the body diameter is so big. I learned I can hold the cartridge in place with a shell holder then screw the cap down on the shell holder.

[dkf]

I use a shell holder for th efew I have to pull. You have to watch though, on stubborn bullets you can mess up the rim of the brass.

[the_ursus]

I’ve heard the new Lyman manual has .458 socom data but I thought I read somewhere that the amount of data published was limited. Anyone here have a copy?

[dkf]

The don't have the new Lyman book. I have the Lyman book for AR rifles and .458socom data is very limited there. I use the data from the Teppo Jutsu website mostly.

[tsubaki]

The data for the .458 SOCOM is the same in Lyman’s 50th Edition as their AR Handbook.
234202

[pmer]

I tried a new mold this weekend. A 459-375 from Mountain Molds, seems pretty good with a couple loads from some of my 405 grain data. Gas checked bore rider with no crimp groove. I got it out of a group buy discussion that seems to have pooped out.

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[diddlyv]

Anyone have a 1200 FPS 500 grain cast load to dupliciate the old TD springfield load

[boman250]

It is not hard to get 500 gr to 1200 FPS. Most people load down to subsonic loads with their 500 gr boolets. I believe I got mine up to 1375 fps using H335.