284 brass sizing..will small base body die resize shoulder ??

42MTD

42MTD

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I just aquired some 284 Winchester brass to reload my 284 with. This size of brass is tough to find so I grabbed what I could get.

The problem is it won't chamber in my match chamber but it will chamber in a friends hunting rifle.

You can see the shoulder is somewhat elongated and does not have the crisp taper to the neck and this is obviously causing the issue.

Will a small body base die help size the brass properly..my Redding FL die does not seem to size the shoulder tight enough.

Thanks

Matt
 
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Matt You didn't say if the brass you "grabbed" was new or once fired? I'm suspecting it was once fired. Full length sizing dies are supposed to resize cases to Sammi specs. New factory cases are usually slightly smaller than Sammi specs so they will chamber easily in pumps,levers and autoloaders. Small base dies are supposed to resize cases back to new factory dimensions . If you have a match chamber you will likely feel some resistance when you close the bolt on a case resized in a small base die but you should be able to chamber it. When you fire that case it will fireform to your chamber and that resistance will be gone. Hope that helps
 
Yes it is once fired brass, but it seems the chamber it was fired in must have had a very "loose" chamber as the shoulder is not as crisp as factory..I tried to chamber it in mine and there is no way I am going to force it more than I have already tried..It certainly works fine in my buddies Remington 284..my dies don't seem to bump it back into a tight enough spec for my chamber.
 
Go a step at a time, in any case I doubt if small base dies are going to solve your problem. Full length resize first, then attempt to chamber the resized case. If that's a no-go, take the expander ball assembly out of your FL die and resize it again. If this works, it might mean that you have to turn the case necks in order to chamber a loaded round in your match chamber. If its still a no-go, get a Redding body die, and bump the shoulder back in small increments until the round chambers. This die will prove to be a handy thing to have around from time to time anyway. Something else to consider is the shell holder. If you're using the wrong number shell holder, or its out of spec, it might be a tad high, preventing the shoulder of the case from being bumped enough during the resizing process.
 
42MTD said:
Yes it is once fired brass, but it seems the chamber it was fired in must have had a very "loose" chamber as the shoulder is not as crisp as factory..I tried to chamber it in mine and there is no way I am going to force it more than I have already tried..It certainly works fine in my buddies Remington 284..my dies don't seem to bump it back into a tight enough spec for my chamber.
Click to expand...

That's right. Standard dies do not resize cases back to factory new dimensions. That doesn't mean there is anything wrong with your dies. Your rifle has a tight chamber and you are likely going to have to use new brass or try a small base die. I have a SB 284 die. If you like send me about 3 of your cases that will not chamber I will size them and mail them back to you. All you have to loose is a bit of postage. If you want to try that, PM me and I will send you a mailing address. I will be away until after Thanksgiving
 
Assuming that you are indeed FULL LENGTH RESIZING (Shellholder bounces off bottom of die) then your issues are more than a SB sizing die could fix, I would suggest finding the gunsmith or owner of the rifle and getting the exact reamer dimensions the rifle was chambered to. It is possible that all is factory except the base dimension but someone that goes to the trouble doesn't stop at base dimension modifications they aslo touch body, neck and lead dimensions. Try measuring a factory fired round from your rifle this might answer some of your questions.
BB
 
I use my small-base dies a lot; often for exactly the same problem that you are having. It comes up often enough, in my case because I have several rifles in the same calibers and some have tight match chambers whereas some are factory. A normal FL die may not resize a case enough to fit in a tight chamber if it was fired in a sloppy one. In extreme instances they won't work between two factory rifles either.

Small base doesn't mean that it just squeezes the base down a bit more, it takes the case down to new dimensions.
 
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