.458 Socom sizing issues at the range today.

[jeeptim]

Had a good range day even though broke my polymer 5.56 lower broke in half an the rear take down pins.
We'll open that in another thread.
So...
Was having trouble with 458 Socom brass not resizing not feeding trouble ejecting every 10 or so rounds. So bought a ammo checker checked all prior to the range.
All fed and ejected even the flat nose lead flat nose p/c and Barry's 350gr plated flat nose.
Had several friends and family at the range was a joy to pass it around all had a good time. Big smiles.
So have a bunch of brass I sent to starline waiting to hear back and have a bunch maybe 30 loaded that are a lil big also waiting on the small base die set.
I posted about this trouble and like troopers you guys came through with excellent advise on fixing this up.
Thank you was a good day!!

 

[LoonWulf]

Glad you had a good day at the range....it's been a while since I've gotten out to shoot for fun.

 

[Blue68f100]

Glad you had a good day at the range.

Who made your upper for your 458 SOCOM?

So you broke a tupperware upper

 

[jmorris]

Was having trouble with 458 Socom brass not resizing not feeding trouble ejecting every 10 or so rounds. So bought a ammo checker checked all prior to the range.
All fed and ejected even the flat nose lead flat nose p/c and Barry's 350gr plated flat nose.

I’d say your “ammo checker” doesn’t agree with your chamber. Although I am not certain about the “not resizing not feeding trouble ejecting” part. Resizing is done on a reloading press, feeding/ejecting will be done on the rifle.

I had problems with the 458 Socom dies from Lee not sizing the case enough for a RRA upper so I turned .010” off the face of the die and it was good to go.

I use stock Colt 20 round mags and they have fed fine for my 458 and 450 rifles. If you have feeding issues, I’d look at the mag. This is assuming you can take (just the upper) a round and drop it in the chamber then (with the charging handle in place so you can get it back out) lower the BCG down and snap the extractor over the rim. If the back of the BCG is flush with the back of the receiver, you should be good to go. If it won’t close at all, you might not have sized enough or you sized too much.

For ejecting it could be your combination of powder, charge and bullet or it could be something with your gas system.

First thing I would suggest is to get some “factory” ammunition. If the gun runs on it, we can eliminate the firearm as a suspect and focus on your ammunition.

 

[jeeptim]

Starline came through like a trooper.
Sent them the offending cases...
Hunter ran them through his Redding dies all chambered after.
Early lee .458 Socom dies were good but not perfect they don't size the last 1/8" or so of the case.
Got a set of Redding small base dies on back order.
I couldn't get past why most sized and some not.
Dies!!!

 

[Toprudder]

For ejecting it could be your combination of powder, charge and bullet or it could be something with your gas system.

Add to that the upper, 458 is a mighty big case and the ejection port is usually milled out much larger on 458 uppers. If cases are not being ejected reliably, look at the edges of the ejection port and see if there are brass smudges that may give an indication of where the problem might be.

 

[jeeptim]

It's the cases that were not sizing.
Until recently I had no case gauge once I found that some cases were not sizing removed oversized cases and the .458 ran well no ejecting issues or chambering trouble.
Once I receive the small base die I think it will be smooth shootin