The concern is magazine feed and slamfires. After you've neck sized a case a number of times (how many depends on how warm the load is and who made the brass) your case body fit will start to get pretty tight in the chamber and you'll eventually need to run a full length resizing cycle to keep them fitting. That increasing tightness, while it's happening, increases the odds a round won't chamber smoothly, which increases the odds of getting an out-of-battery slamfire due to the added chambering resistance.
If you want to keep experimenting with it, that's up to you. But as a courtesy to others, please stay at the right end of the range when chambering these to make sure nobody is to your right. Nothing like hot, sharp brass and bolt face fragments to ruin the day of the person to your right if one lets go.
One fellow on another board used to be test director at Aberdeen Proving Grounds. He said he once investigated an out-of-battery slamfire in a machinegun that killed the soldier to the right of the ejection port. So, even if the chance is one in a million against it, prudence says you'll feel a lot worse if you not only turn out to be that one in a million guy, but then also have the injury of another person on your conscience.
Glen Zediker suggests that you will be fine setting the shoulder back 0.002" at each loading. That is, you can tighten the neck in the collet die, then use a body die to set the shoulder back that far, and it will feed. For single loading 0.001" setback is good enough. Plus, several benchrest shooters claim they get better accuracy that way, they believe it to be due to allowing room for a bit of cartridge body self-centering. Worth a try, anyhow.
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