Small base sizing for .30 carbine??

OK, I did manually run a few empty cases of each brand that are being used and all chambered very easily, including the LC military that were the worst offenders of all. However, as reported in a previous post the steel die has been received and all cases were sized first with the steel die. The bases on all cases were sized to .348 or .3485 which is an improvement over the carbide sizers. Also cleaned out the chamber and removed a circular ring of copper that had apparently been the accumulation of copper from the plated bullets. A similar ring was also removed from the chamber during an earlier cleaning. So things seem to be looking up.
 
Bottom line: steel sizing die resolves sizing problem for new mfg Inland carbine.

Using a second micrometer where a Sierra Match King 168 gr bullet accurately measures .308, more meaningful results were obtained for various measurements with the cases used for reloading. The following figures all represent base measurements at various stages of the firing, sizing, etc operations:

Federal brass
New factory ammunition. .352
Fired in old military carbine. .355
Sized with carbide die. .355
Sized with steel die. .354

Winchester brass
Reloads fired in military carbine .355
Brass then sized with carbide die. .355
Brass sized with steel die. .354

Armscore brass
New factory ammunition. .352
Brass then fired in military carbine. .355
Brass fired in Inland carbine. .352
Fired brass sized with steel die. .352

LC military and Remington brass
Essentially the same
New unfired brass. .353
Loaded and fired in military carbine .357
Loaded and fired in Inland carbine .355
Sized with steel die. .354

All loaded brass sized to .354 or less chambered properly in the Inland carbine thanks to the steel die. A few sized to .355 were tried but would not chamber reliably but all chamber in the military carbine and will be used with it.

Maybe .001 difference with the steel die doesn't exactly qualify as small base but it was enough for satisfactorily reloading with the Inland and might be a necessity with others. The carbide dies just weren't quite sizing enough at .355.
 
Based on the info; you have a tight chamber.
I have run across this only once with a 30 carb rife and it was on one that had a new after market barrel installed.
Sent it out and had the chamber reamed and never had another issue.
Case length is the most common issue with 30 carb not cambering since it head spaces on the case mouth.
 
Note that on about all failures to chamber, it is still lacking 1/4 inch from chambering which would seem to eliminate case length as an issue. Most of the brass is new or once fired. I've mentioned cleaning out the chamber after firing sessions and every time a ring of copper, or copper flakes, I'm assuming from the plated bullets, are removed by the cleaning. Perhaps that copper build up could have something to do with things. Chambering does seem to improve after each cleaning.
 
More and more cooper rings it seems left in the chamber after each shooting session that can't be helping the situation and perhaps a major contributor towards the chambering hang up. I've been using x-treme plated bullets; would you think a more sturdy fmj bullet would prevent leaving the copper rings in the chamber, and what bullet might you suggest? Invariably each carbine behaves better after chamber cleaning. Today even the military carbine got to the point where the rounds refused to feed and previously this was unheard of. The Inland accumulated more of the copper rings than usual.
 
Well I think I've finally got the chambering problem solved. As pointed out several times, the steel sizing die reduces the base to .354 as opposed to .355 for the carbide dies. That's all well and good but not the whole picture. Most of the times the rounds jam when they are only half chambered and at that point are tightly jammed, often requiring taps with a mallet to dislodge and clear the round. This would suggest that the hangups are occurring at the case body and not just at the base.

Back to the carbide dies. It turned out that sizing with the carbide dies reduces the case body near the center some .002 over the steel die at the same location. So the outcome has been to use one of the carbide dies along with the steel die. Using a Dillon 550 the steel die with decapping stem is placed at station1 and a carbide die with the decapping stem removed placed at station 2, leaving stations 3 and 4 for powder charging and bullet seating. This sizing technique, chambering the sized cases without bullets yet seated, for safety considerations, provides excellent chambering without a single hang up and with all five case brands being used.

These newly sized rounds were then loaded with Sierra 110 gr FMJ bullets which hopefully will eliminate the copper rings being left in the chamber by the plated bullets. Test firing with the new rounds will take place in a couple days when the rain subsides here in the southland.
 
You must log in or register to reply here.
Back
Top