458 Socom feeding problem

[Circuit Rider]

A friend recently purchased a Rock River upper,458 Socom. He left it with me to work out a problem and work up some loads. He was told, and I called R.R. this morning and was told also, the 223 magazine would feed fine single stacked. Not happening, jams each time it tries to feed. It appears the larger brass is held too low for it to feed properly, too much angle. Looks like the top of the magazine needs to be opened up to let the round ride higher thus feed at less of an angle. Not a 'smith so just an old man's opinion. Any help would be appreciated. Circuit Rider

[Lloyd Smale]

first try a differnt magazine. If that doesnt do it consider polishing up your feed ramp. Id also give a different bullet a try. Some guns just wont feed a particular bullet.

[Circuit Rider]

 Thanks Lloyd, I tried a 3 different mags, didn't help. Going to try different ammo, some we have loaded, with different bullets. Circuit Rider

[Lloyd Smale]

I know my beo can be fussy about some of the bullets ive tried. Also seating dept is real critical in them. Even if you try seating your bullets a bit longer and shorter and seeing if that helped. I just bought a bushmaster in 762x39 and it was nose diveing all the rounds into the feed ramp. the bullets looked to level in the magazines. I sent it and all the mags i bought to bushmaster and what they did was polish the feed ramp and repaced the mags with mags that had heavier springs. If you have the time go to wolf springs and buy a extra power mag spring for a ak47 and put it in a 30 round ar mag. Alot of guys with 762s do this and it helps and id bet it may help in your case too. if you want to try it email me at lws43@hotmail.com and ill send you one as ive got some extras and if it works you can order one and replace mine.

[Circuit Rider]

Thanks Lloyd, my friend purchased some pieces for me to try with the Socom, and I'll report when I see what I've got. He drives long haul, so I'll have the weapon for a month or so to play with. Yes I'll try different seating depths and bullets also. Circuit Rider

[RB1235]

Loyd is giving you some very good info I am trying to post some load data for you I found online.

 I have a good 300 gr rem jhp load at 2.08" col. And a good 500 gr hornady rn at 2.25". I dropped way down from the data provided and hope you will do the same as they are max to reach a computer generated 35,000. I dropped 5 grains for a start then stopped a little short of their max when groups started to open up.

Mine runs c-products and usgi mags in 20 and 30 rnd with + power springs. Still have the 5.56 followers in them. Just made sure the rounds would clear the lips. The chamber was polished. What I'm trying to say I guess is to listen to this guy, he will get you running good. I went through this problem last year. It was extremely frustrating since I could never find corbon bullets to get a col off of. The key to getting it cycling right was the col, but I would do the other things over again as well to ensure better cycling. I don't shoot as much as a lot of folks. I have maybe 350 rounds through mine since it has been running good without a hiccup. Wasted a good 100 rounds with it jamming 300 gr at 2.25" col.

[Circuit Rider]

RB, thanks for the info. Yes, I know Lloyd knows of what he speaks. Being an old coot, I'm going to print out the info and have it to refer to and not depend on my memory. Circuit Rider

[Circuit Rider]

Guys, wanted to let you know what we found with the 458 Socom feeding problem. Didn't matter what bullet or load we tried, it would only feed one or two without hanging,sometimes none. Finally found that  Rock River is having problems and we're sending it back. Thanks for all the help, Circuit Rider

[Lloyd Smale]

hope they get it worked out for you. there cool guns when there running right