I bought a 458 upper a little while back. When it arrived, I was a bit surprised to find that it had no ejection port cover, no forward assist or brass deflector. I do not care about the lack of forward assist or cover, but the lack of a brass deflector may be a hinderance to shooting left handed. The upper was also too thick to fit well in my upper vise blocks, but they fit well enough to get the barrel nut off. I will be turning down the barrel for a suppressor.

Anyone know how to install a brass deflector? I'm thinking that a shaped piece of aluminum or plastic epoxied onto the upper might work. Any ideas? I might put a brass catcher on the upper soon.

I loaded up 405 grain cast and jacketed (remington) bullets with WC820(like H110) and pistol primers. While 17-18 grains gave me about 1050 fps and good accuracy, they did not eject the brass. Even loads up to 21 grains moving at 1250 fps would not pick up the next round in the mag or hold back the bolt on the last round.

I am not complaining about the new upper, it is a light, short and handy carbine that I enjoy shooting. I just need some hints on how to make things fucntion better. I'm thinking of casting bullets up to 500 grains, or installing a lighter spring or recoil buffer. Would a slower or faster burning powder change things enough to make it run right? Thanks.

Ranb

This is a nice cartridge with potential, but lead bullets? Might they not block the gas port eventually? Regardless I recently had the opportunity to fire a Rock River .458 socom and would recomend sticking with the jacketed bullets. As to brass deflector, if you are using a flattop maybe juryrigged something could be hung off that. On the buffer/spring I don't know what you are currently running so I don't know if lighter would help or not. Lighter buffer would be more recoil and wear, but for a dedicated load for subsonics... I assume the can will be able to handle the gas volume and pressures of a rifle cartridge? Port pressure and dwell time affect the cyclic action rate and impluse, so good luck on that front. Enjoy the big boy! My pet AR sports the bastrad child 7.62 X 39, a fine little .30 it is!

I honestly don't know anyone else shooting cast bullets in their SOCOM, including me but I can tell you that Reloader 7 works well for me. I use up to 41 grains with 350 gr bullets and up to 43 gr with 300 gr bullets. You might want to try about 38 gr with the 300 gr cast bullets and work up slowly until it cycles right.

I tried 296 which behaves just like H110 in mine and had cycling problems that I think were due to uneven ignition. The pistol primers just don't light off small charges of 296/H110 in such a big case very well. I would think cast bullets have such low starting pressure that they would be even worse.

I use 500 gr Hornady soft points for my subsonic loads. I'll have to check the charge weight but it is a lesser charge of Reloader 7.

do you have an adjustable gas port on it? Actually before you get that far, I would talk to Marty from Teppo Jutsu, or the individual you purhcased the upper from. If you did purchase it from Marty, he has a handle in accuratereloading. I believe it is MartyTW.

http://www.laser-cast.com/AboutTrueShot.html

try using these...you will have less typical lead issues. good luck

One thing I should have mentioned, I am keeping the velocities subsonic, partly for sound suppression, and to keep the recoil low. This cartridge when subsonic uses less powder than the 44 magnum, so I would put it in with the pistol rather than the rifle loads. The suppressor will be an aluminum can on a form 1. I will get a hold of Marty, it is one of his uppers from a dealer.

Ranb

Yes,
please do talk with marty on these things.

since this is a GAS operated action, I would not expect it to use the same gas system settings as a supersonic load..volume and velocity of the gas will be different, and lower, in your load vs a supersonic load.


If you intend to ONLY shoot subsonic, I have little doubt your AR will need a tune-up to work in that envelope..


but, try this.. run some 405s at full speed and see if they exject propery

jeffe

If you shoot light bullets subsonic you won't have enough gas volume to cycle the action reliably; that's why it was developed for the 500 gr bullets. The rifling twist is set so they are very unstable at that velocity range. They tumble when they impact and are devastaing for hunting. They don't have much recoil, either.

BTW, I ordered mine without the forward assist and cover too. Wish I hadn't. I am going to have the barrel switched over to my old 223 upper to get that stuff back.

You might get where you want to be with an adjustable gas block but then you're always fiddling back and forth and if you forget in the middle of a hunt, well, you just lost your second shot or worse.

If you stick with the round's performance as designed, the gun functions fine with a standard fixed gas port. Shoot the light bullets supersonic and the heavies subsonic.

I got a reply from Tromix saying the 500 grain bullets should be better. I will try those, then a differant powder if needed. I'll go with a lighter spring before I mess with making the gas port larger. Thanks for the help.

Ranb

I believe there are adjustable gas cylinders that replace the recoil spring. They are supposed to be better for the gun and the shooter. They eliminate the "POING-Chang-Ching" you hear through your cheek bone with the AR. May help your problem too.

Since 400 grain loads would not bring the bolt back far enough to extract the spent case, I cast some 500 grain bullets from a Lee mold. The experiment ended as soon as I tried to chamber a dummy round. The ogive of the Lee bullet is about .450†and the barrel throat is short and narrow. The rifling engages the ogive just in back of the nose. The Lee bullet would have to be seated with the crimping groove down to the shoulder to chamber a loaded round.

Does anyone know where I can get a mold that drops a bullet with an ogive equal to or less than .445 inches? Commmercial cast and jacketed bullets have ogives of about .445 inches and chamber properly.

Does anyone know where I can get a mold that drops out a bullet with an ogive equal to or less than .445 inches?

I might try cutting the spring this weekend to see if the 400 grian loads work. How much of the spring can I cut off and still expect it to have enough force to chamber a round? Thanks.

Ranb

It isn't bullet mass that cycles the action like a blow-back pistol, it's gas pressure. It simply won't work right until you get the pressure/time curve correct for that mechanism, regardless of what weight bullet you are loading.

As to cutting the spring; well, we won't even go there. Stop before you either ruin the rifle or hurt yourself.

quote:

Originally posted by tiggertate:
I believe there are adjustable gas cylinders that replace the recoil spring. They are supposed to be better for the gun and the shooter. They eliminate the "POING-Chang-Ching" you hear through your cheek bone with the AR. May help your problem too.

That sound gets so annoying after a while. After a while, that noise gets louder than teh muzzle blast.

If you have to, send your rifle back to whomever you got it from with some handloads, and ask him(or her) to make it work. So what did Marty have to say?

Have you posted this over @ the AR15.com forum?

I wrote to Tromix, they said to try the 500 grain bullets.

Ranb

oops, I missed that part. you get the bullets yet?

Can not find any .458 500 grain bullets in western Washington, have to order them. I am getting a Lyman 1-Cavity Bullet Mold #457125. Hopefully this heavier bullet along with a 20 grain or so powder charge will do the trick.

Ranb

Please TRY loading 400 to marty and harry's spec and go shoot them... then report back on if that made it cycle due to gas pressure/volume

I loaded some 405 grain bullets with a full charge today, they operated the action correctly.

Ranb

Ran,
excellent news... if you would like subsonics AND full house, you might call marty and talk with him.. good guy, just remember he's running a biz

jeffe

31.1 gr of Rel 7 will get you high 1300s with the 500 gr Hornady RN and 2.225 COL. That's Marty's numbers. I load 28 gr and get just under subsonic with the same bullet. With cast bullets you may need to drop it a little due to lower friction.

The 500 grain bullets out of the Lyman mold were just the ones I was looking for. I am able to load the cartrdge to an OAL of 2.26" and they chamber without engaging the rifling. 21.9 grains of WC820 gives 1067 fps but with a spread of 55 fps. I will try magnum primers to see if they provide more uniform ignition.

The brass extracts and ejects well clear of the action. A few of the brass hit my shoulder, but none them hit my face, I guess it does not matter if the upper has a brass deflector or not, problem solved.

I had to use the pistol range to clock the ammo, so I was not able to test for accuracy. I have added a muzzle brake to vent into the silencer I made for the upper, but it should not affect accuracy much, I hope.

All and all, this upper is a very nice addition to the collection. The 458 socom is more fun to shoot than the 300 whisper (tame) or the 510 whisper (punishing).

Ranb

Good deal! Do you shoot cast bullets in the big Whisper too? Sounds like a decent hog gun.

Yea, Maybe I need to look into that 500! Glad to hear you got your problems sorted out. Who knows, maybe a shorty 510 on a bolt action could be pretty cool. Let us know how accurate your gun is with that load. Take pics of targets and post em in the fav loads forum!

I normally use surplus M33 bullets in the 510 whisper. The barrel is an SSK 20" stainless machined down for my silencer. My Encore is a 2 moa gun when I shoot surplus bullets, even less accurate with cast 950 grain bullets from a CBE mold. The rifle shoots poorly when on a bipod, but improves when shot from a sandbag. Best accuracy is when using Amax. The recoil was enough to wreck a tasco SS scope, a redfield, and strip the forend screws. It has also damaged my Leupold VX3 mag adjustment.

I have not heard too many complalints from those that shoot this cartridge in Sako or Remington bolt guns. My Encore weighs only 7.5 pounds with the scope. The silencer weighs two pounds and takes the edge off of the recoil, but as I live in WA state, I can not use it much. I need to get my hands on a 500-600 grain mold for the 510W.

Ranb