17-223 ackley problem

[ok41]

Anybody have advice or experience with sizing 223 brass into 17-223? I just received my VERY EXPENSIVErcbs dies for forming 17-223 ackley from 223 brass. Being trying to size brass, looks good, but won't chamber (bolt won't close). The dies were made from a chamber cast and the rcbs tech had a chamber reamer in the same caliber to check headspace, so I don't think the dies are off, but what's outta whack?
The rifle is a Sako L461 that was barrelled by Ackley and has been fired (I assume) as it's 25 plus years old, with a nice Lyman scope.
What am I doing wrong?

 

[Vern Humphrey]

First of all, what is it you're trying to chamber -- a sized case, or a loaded round? You should try the former before the latter.

Have you full-length resized the formed case after forming? Are you loading the sized case with a stripped bolt, thus ensuring that extractor, etc., and not interfering?

If an empty case won't go with a stripped bolt, try smoking the case and re-inserting it to find where the interference is.

If it's a loaded round, your problem may be bullet seated out too far, or it may be the neck needs thinning.

 

[ok41]

I am only trying formed cases, no loaded rounds, and yep, they were full length sized before forming the neck down to .17. And while it appears they will drop into the chamber, the bolt will not lock. I have forced bolt closure before with other calibers and old 98 actions with no problem. Butr the 461 Sako is a delicate little thing and I don't feel I should force battery.
Been loading since early sixties but never formed cases from other calibers.
Will try the smoking on a round to see if I can identify the resistance. Thanks for the info.

 

[dcloco]

A green, blue, or red Sharpie works well...instead of the smoke trick.

Did you neck turn the brass?

 

[Vern Humphrey]

they were full length sized before forming the neck down to .17

Full length resize them again, after necking down and see if that solves the problem.

When you force the neck into the .17 die, the case walls are stressed and may slightly bulge. Full length resizing ought to iron out that bulge.

 

[ok41]

Thanks for the tips, fellas. Moving kinda slow this morning. Haven't had a chance to 'play' with my new dies yet today. Wil try marking a case to see where resistance is and will full size again, but I don't think that's the problem. The new sized 17 case drops freely into the chamber, I just can't get the bolt to close down on it. I trust RCBS to have made the dimensions correctly or I would think a problem may be headspace from the newly formed case? In reducing the neck to .17, did I perhaps make the case a bit too long?
I miked the new case and compared it to a sized .223. They are still the same length. Matbe I'm holding my mouth wrong?

 

[highlander 5]

If you can get a few fired 204 Ruger cases and reform them that might solve the problem. Resizing from 20 cal to 17 cal might stress the case less. This is a guess as I don't have 204 Ruger case dimensions handy

 

[Vern Humphrey]

I would think a problem may be headspace from the newly formed case? In reducing the neck to .17, did I perhaps make the case a bit too long?

There are several possible problems:

1. The case walls are slightly bulged from the pressure needed to force the .22 neck into the .17 die.

2. The case is slightly stretched from dragging the expander ball back throug the neck (use more lube.)

3. The neck is too long after re-forming , and is entering the throat. Trim.

4. The walls of the neck are too thick (you'd usually see this with a loaded round, not a case -- but could be.) Neck turn the brass.

5. The dies are not to spec -- but full length re-sizing after forming should cure this problem.

6. You are not using a stripped bolt to test the cases -- the extractor is preventing the bolt from closing.