This is a good topic as long as we are not talking about bench rest rifles.Just factory rifles being shot by people trying do what the bench rest shooters do.
The conversation usually stars with
" hey I just want to ring out every bit of accuracy from my brand X rifle "
Or
" My factory rifle with it's sloppy factory chamber shoots an inch and I want to give it every chance I can to shoot better. "
Fact is with a factory rifle I think you are wasting your time. Now most folks defend what they by and what they do, No matter if it's right or wrong. No matter if they wasted there money or not. Some folks just got to be right and will never admit they made a bad choice. Just human nature, or perhaps nature of the beast.
Bench rest shooters turn necks and get crazy over Concentricity for a reason, But not the same reasons we do with factory rifles.
notice I said we, yup I don't exclude myself from the got to make it shoot better crowd.
I have the tools, spent the money, got the T-shirt and now I watch them sit on my shelf.
Got the Sinclare and the Sinclare neck turner. I learned how to use them and of that I am happy. It made me feel good that I was doing my best, and it also gave me something extra to do. Ha-
not like I didn't have enough to do already.
If you have a factory rifle that shoots 1" or an 1 1/2 at 100 yards I think we can agree that's not to bad.
Is it great? no but it sure ain't to shabby, Yes I have made factory guns shoot 3/8 of an inch with very carefully made hand loads and some varmint rifles that shoot 1/2" with good factory fodder.
Fact is factory guns are made to a rather wide spread, + or - standards. ( in spec out of spec )
A rule of thumb for me is; the tighter the specs, the better the material and tooling--most times will give us the best piece of goods Eh.
Notice I did say most times A guy has to be a little careful of what he has to say or the old>>>>>>>>>> and young Flame police are on his but.
If your rifle is shooting 1' or 1 1/2 with factory ammo you could most likely get it to shoot a 1/2 " better with hand loads, 1 1/2 to perhaps 7/8 " and the 1" gun to maybe 1/2 or 3/4.
Now if you start messing with the necks and chasing the Concentricity Rabbit he will take you down many holes,
and how much do you think you will shave off those groups ? Perhaps 1/16 of an inch ?.
If you shoot the same way every time you shoot, the weather and atmospheric conditions are the same,
You are in a good frame of mind ( good karma ) and all the planets are in line
you may see the 1/16 " improvement.
If your rifle shoots 2'' or more groups at a hundred yards you have a lot more to look at other than necks being straight.
But if you do decide to go after the problem--lets ask the question ? when are the case necks the straightest ?
I am going to say right after the round is fired and carefully extracted. Why? because at that time it is a reproduction of your chamber and if your chamber is straight the necks should show 0 to .0005 run out. If it is much more your chamber is out. So now we at least know if our chamber is straight before we go any further along.
Also I am going to see how big my chamber is in relation to my loaded round ( chamber slop )
I am going to measure a loaded round at the neck. Lets Say it's a 270 Win.
and the loaded round at the neck is .305 and after the round is shot the neck is .308 well thats not to bad
.003 bigger than before it was shot. I know--spring back-- but I am keeping it a little simple, most factory chambers will be a lot bigger than that.
Anyway I have found that I have .003 or .0015 on each side of the neck. Yes that is if I start with all the brass the same neck thickness. Most of the 270 Win. brass I have seen is about .014 thick at the neck.
Why would I want to turn those necks and make them any smaller and add to the chamber slop ? I want them to be as close to at the very least .0015 smaller than the chamber neck, for a hinting rifle .002 is even better
for safety. If I turn them they ain't going to get bigger Eh. Necks are turned on custom chambers that have been ordered a little smaller so the loader can custom fit them to his custom chamber size. No other reason.
Lets not forget that a turned neck may not have enough neck tension if you use a normal factory sizing die.
A custom die may be needed or a least a bushing die that will allow you to size down enough to make up for what you have removed. Yes I know, I have been told, Hey I just want to even the necks up a Little and take a skin cut off.
It ain't going to do much and all you are really saying is you want to play with a neck turning tool.
I will say if .014 necks work well and I have some that vary .014 to .015 I may turn them down so they are all
.014 round the whole neck. Helps to even up bullet release and pressure to some extent,
but not a whole heck of a lot in that factory rifle. But I feel better about doing it.
So anyway now that we have those nice straight necks after firing what the heck happens to them when we reload them and find they are .005 or .006 out.
But remember those rounds shot some very nice groups out of round or not.
Well this may hurt some feelings but IMHO the worse thing you can show a neck if you are trying to keep it straight is an expander ball, why? because if your die does size the neck straight there is a good chance that when that ball is forced back out of the neck it will take it out of round. This exercise requires you check a neck after every change you make to it. Only way to see how your screwing in up.
I like a body die if my cases have gotten to big to chamber or I want to just bump the shoulder back a little,
and then a bushing die for the neck. Or a custom die just to squeeze the neck down for the correct bullet fit.
It's getting to sound like a lot of work for that 1/16 of an inch improvement isn't it.
One of the best things you can do is to simply use a Lee collet die that only squeezes the neck
( I didn't say sizes the neck-- I said squeezes the neck ) Yes they take a little working with some fine 600 grit paper around the collet and proper Lubrication, but ons done they will give some of the best straight necks for the least effort put in. After 4 or 6 firings the case body may need resizing, use a body die and leave the neck alone.
Next is the bullet seating, Use a good die that will allow you bullet to be seated straight and go and shoot.
.002 or .0035 run out is not going to hurt your factory rifle.
We all have different personalities and if you are the type that must have every thing just perfect to the point of being a little anal--then by all means do all you need to do in order to satisfy that need.
I can say that because I can be that way myself
But a guy has to no when enough is enough, and the limitations of his equipment.
I know there is no telling the so self proclaimed experts anything, but perhaps a new guy might benefit a little and have a little more money in his pocket for some other things. Like a good reloading book.