IMO... NO...there's enough gap in a factory chamber to begin with, I usually get .006-.009 per side in a factory neck when measured. Unless you got a rechamber/new cut smaller your just going to make the gap larger in a factory rifle overall something you don't need or want. Modern brass may need a little cleanup BUT not in a factory hunting rifle...IMO
Is it worth it.If so should I buy inside pilot-reamers or just use case trimmer pilots?I don't know much about it.
The answer is maybe!
Seriously, I have never had a 'need' to turn necks on most all of my brass. However, when I have to make brass (8x57 or 7x57 to 257 Roberts) the necks get pretty thick and I get a donut inside as well (on the 8mm to 257 convert). I have to ream AND outside turn the necks....fortunately I can do it all in one pass with my trimmer.
You really under estimated the ramifications of the boondoggle you have just perpetrated!
Thanks for the input.I decided to buy 200 bullets,superformance powder and 6 Hornady die lock rings to test.Let you know how it works out in my 22-250 40 XB.I really think the lock nuts are better than the RCBS type.I will let you know.My birthday present to myself.I already have 100 neck turned brass for this rifle.
Neck turning factory chambers to make them uniform probably won't hurt, but I also don't think it will make a noticeable difference in accuracy. You would be much further ahead to use bushing dies and only size a portion of the neck. You will see an improvement on factory chamberings using that method.
The donut formed on the inside of the neck is common after multiple firings. The best solution is to keep your bullet seated out far enough so it doesn't come in contact with the donut. Some guys use inside neck turners to combat that problem but I never have.
All of my comp guns have tight necks, with a clearance of .0015" to .003" overall clearance. They are all very accurate but I cannot say such is the most accurate based on the cleance between the case and chamber wall. I certainly wouldn't go more than .003" on a comp gun.
If I were to build a custom hunting rifle I'd probably go with a custom chamber that didnt require neck turning, but who knows, I like accuracy so maybe I would just to get that extra little bit squeezed out of it