spring back on brass

joes

I am shooting range brass 308- all federal head stamp. I have loaded the brass one time with "several" giving a hard bolt close. On the second load there are many more that has resulted in a hard bolt throw. I full length size- even went much further than touching the shell holder pushing the shoulder even further back (after the FL did not do the trick), and trimed all cases. If it is spring back is there something I can to save the cases? Will another loading with the stiff bolt form closer to the chamber? TY.

243winxb

The web area near the head is not sized by most dies. If the brass was fired in another rifle with hot loads, the web could have expanded, causing hard bolt closing. This is not corrected by more firing. IMO. You could try Small Base Dies. These dies push the shoulder back a little more, and size the case body differently.

joes

I just read RCBS does not recommend small base dies for bolt action rifles...? Is it OK to use?

gcs10

Small base dies are not normally needed for bolt action rifles but can be used. The small base die sizes the base of the case while normal dies do not. Sizing the base just works the brass more. This can lead to early failure of the casing. Automatic rifles sometimes need cartridges resized with small base dies in order to chamber properly. In your case, if the web of the case is oversized then resizing with a small base die will fix the problem.

Measure the case at several spots along the entire length of the case and compare the measurements to a factory new cartridge and/or dimensions listed in most reloading manuals of the correct readings for a SAAMI case. You will probably see what is causing your problem. If the base is oversized, then you have to decide if the "free" range brass is worth the cost of a small base resizing die.

Cort

Rocky Raab

I think you are OVERsizing them. When you come down that hard against the shellholder, you force the brass to flow to wherever it can - and that is often into that unsized area inside the shellholder lips.

That also can cause excessive headspace if the dies and your chamber aren't a perfect match. Unfortunately, the next firing can cause the cases to crack or stretch just above the web, which ruins them. There is no way to fix the problem, if that's it.

If you have any fired but unsized cases, try backing the die out at least a full turn. Test a sized case in the gun. If it chambers smoothly, chances are the problem was oversizing. If not, it could be case length, so measure that case and trim if needed. Try it again for smooth chambering (but don't size it again first).

If that test case chambers smoothly, lock the die. If it chambers with only a little "feel" on the bolt, begin turning the die in a fraction of a turn at a time until the case chambers with only the barest whisper of feel. Lock the die. This is your semi-final setting.

If subsequent firings start to chamber a bit harder, screw the die in one more fraction of a turn - not over 1/8 turn. That should be the perfect setting for that rifle. Check case length often as that can also cause hard chambering.

joes

I measured the base as suggested and the fired cases are larger than the unfired ( by .02- Does that mean my chamber is larger causing the cast to fire form to the chamber size? If so will I always need to small base size the cases after each firing?

Rocky Raab

Maybe not. I still think your expanded bases are from oversizing. The unsupported base area of the case is simply "smooshed out" by the die. Back out the die as described above and try one case. I bet ya that fixes the issue - and saves you the cost and trouble of using a small base die.

If that is a fired but unsized case, your load may be a bit too hot. Federal brass is often a wee bit softer than WW or RP, and can swell more with a given load. (It can also be thicker, which only makes a hot load even hotter, in effect.)

243winxb

quote: the fired cases are larger than the unfired Your loading is to hot, you are expanding the web area. Primer pockets will also become loose. If there was something wrong with the brass below the web, towards the shoulder/neck area, firing would expand the brass to your chamber and spring back, fixing your problem. But the web is much thicker and should never expand with normal pressure loads. Brass fired in a machine gun or M14 may be larger & require a small base die.

243winxb

SAAMI drawings give the measurement for brass & chambers here >http://www.saami.org/specifications_and_information/index.cfm?page=CC Web maximum is .4703" Here is the 308 drawing> http://www.saami.org/PubResources/CC_Drawings/Rifle/308%20Winchester.pdf