neck turning?

[TrxR]

If a person had a barrel chambered for no neck turn lapua the decided down the road to start neck turning just enough to uniform the necks. Would that cause problems? Also would the routine for doing this be run a expander through the necks then set the cutter to just take enough to uniform? Would you then resize or resize before?

Thanks

 

[lrgoodger]

Wouldn't hurt a thing.

Yes.

Yes, re-size after turning.

 

[Martin52]

If a person had a barrel chambered for no neck turn lapua the decided down the road to start neck turning just enough to uniform the necks. Would that cause problems? Also would the routine for doing this be run a expander through the necks then set the cutter to just take enough to uniform? Would you then resize or resize before?

Thanks

I don't think this would cause problems (should be an improvement IMHO!) provided you do not cut too deep (and I note you do refer to cutting just enough to uniform). I would run an expander through the neck first, then cut, then resize the neck (assume case neck mouth chamfered etc).

Martin

 

[M-61]

It would cause no problems and if turned correctly you will have a uniform neck thickness (or at least better than unturned).
Depending on the brass you may be surprised at what amount turns off one side.

 

[searcher]

As M-61 stated, you may be very surprised by how non-uniform some brass is - even the "good stuff' such as Lapua and Norma. Even if you only do a very light turning (where, say, 40% of the case neck had any brass removed) your brass will be better than it was before. When you size necks with thick areas on the necks, these thick areas get pushed to the inside of the neck. A subsequently loaded bullet is pushed off-center in your neck, creating a round that is not concentric and will not be in-line with your bore-axis when chambered and fired. Turning any high spots off helps minimize this. Oftentimes when just skimming a little off, you will enevitably find a few cases that were REALLY out of whack where no brass comes off at all - and another one or two where brass comes off 100% of the case neck. Getting those uniformed to the rest of your brass can make it worthwhile all by itself - though the really bad ones can be weeded out by measuring your case necks individually - but not as accurately.

 

[TrxR]

What is the best way to determine how much is needed to be taken off or where to set the cutter ?

Thanks.

 

[searcher]

I'd set your cutter to where it goes over your entire neck on a test piece of brass without taking any brass off, then making gradual cutting depth changes and going over the neck again until the cutter starts cutting. I would stop making depth adjustments once your sample brass has about 15% to 20% of the neck shaved (the remaining 80% thinner portion of the neck will not have had contact with the cutter). Then, I'd try a few more pieces of brass to ensure your sample was indeded representative of your lot of brass - cutting approximately the same amount off. I say this because you will find a few really bad pieces and, ideally, you don't want them to be your set-up sample piece. Once you find that you are typically taking off about 20% on average, Id increase your cutter depth to take off more until your half-dozen cut pieces now show about 40% of the surface area to have been shaved. This will make an improvement in your loads by making tem all a bit more uniform - and taking the really bad ones out of play as they were. You may be left with a coule of pieces of brass that never made contact with the cutter. I personally toss them.

You can go more if you wish, but be advised you may need to go to a bushing resizing die to get regain neck tension if you go too far. Going to a bushing neck die would be a great additional step if you don't already use one anyway. If you already use one - you may find you need a smaller bushing.

 

[searcher]

On the first part of your question - good to run an expander into your necks (I use the Sinclair model) then turn necks, then resize. I also (but not necessary) anneal my necks prior to expanding.

 

[TrxR]

Thanks searcher. I am going to be ordering a set of Whidden bushing dies here soon .

 

[BoydAllen]

Depending on the chamber's neck dimension, the brand of brass, and the intended use of the rifle, I might not turn at all. Years back, I did a test with a factory .222 that I had bedded and floated, and worked up a load for, comparing cleaned up turned necks with unturned. There was no advantage to turning that I could see on the target. Tell us about your rifle.

 

[TrxR]

I havent got the rifle together yet but it will be a 308 with a 30 inch heavy palma barrel for F/TR . I will be using Lapua brass. I will also be using one of PT&G 's reamers. Probably his F/TR reamer for unturned necks . I havent decided totally on whether i will be using 155's or 185's but will have to decide before I order a reamer.

 

[BoydAllen]

For competition, I might figure out what neck thickness would give a reliable complete cleanup, what clearance I wanted in the chamber, and order the reamer with a specific neck diameter to achieve that clearance with that neck thickness. To determine the correct neck thickness, I would buy a good quantity of brass from the same lot, and to some turning.

 

[M-61]

Depending on the chamber's neck dimension, the brand of brass, and the intended use of the rifle, I might not turn at all. Years back, I did a test with a factory .222 that I had bedded and floated, and worked up a load for, comparing cleaned up turned necks with unturned. There was no advantage to turning that I could see on the target. Tell us about your rifle.

I would agree with Boyd's reply, however I noted he incorporated the phrase "Years back", and regarding a .222. My experience of years back is the early 70's with .222. I found the brass then manufactured by Remington was really first class ( I still shoot some of it). I don't even know if Lapua was made or available in this country then. You inquired about Lapua and it is top shelf. I would take a few sample cases, put them in the turner and see if indeed they are as concentric as they should be. And as Boyd asked let us know your results. There may be no noticeable improvement but if you don't try you won't know.

 

[mikecr]

I would take a few sample cases, put them in the turner and see if indeed they are as concentric as they should be

Couple problems here:
-You can't tell anything about case concentricity, eccentricity, or runout using neck turners(they are not measuring tools)
-New, unfireformed cases, are not normally concentric -yet(you have to make them so)

You need the proper tools to determine these attributes(like a ball mic, and runout gauge)
I agree with Boyd. Clean up some necks from a lot & order a reamer producing desired clearances.
If cleaning up necks still leaves you with reasonable sizing/clearance in an existing chamber, than it won't hurt to do so.
If the gun shoots fine and you're producing low runout unturned ammo (as measured off seated bullet noses), then there may be no reason to turn. Or, there may still be a need, if necks are too thick and causing big tension variances.
It is possible to produce & measure ammo with very low loaded runout off noses, even with cases exhibiting high thickness variances.
If these cases are put through heavy sizing cycles, then runout will still grow with each cycle. But, if the gun is shooting good enough with it, well then that pretty much trumps all else.

 

[M-61]

I would take a few sample cases, put them in the turner and see if indeed they are as concentric as they should be

Couple problems here:
-You can't tell anything about case concentricity, eccentricity, or runout using neck turners(they are not measuring tools)
-New, unfireformed cases, are not normally concentric -yet(you have to make them so)

You need the proper tools to determine these attributes(like a ball mic, and runout gauge)
I agree with Boyd. Clean up some necks from a lot & order a reamer producing desired clearances.
If cleaning up necks still leaves you with reasonable sizing/clearance in an existing chamber, than it won't hurt to do so.
If the gun shoots fine and you're producing low runout unturned ammo (as measured off seated bullet noses), then there may be no reason to turn. Or, there may still be a need, if necks are too thick and causing big tension variances.
It is possible to produce & measure ammo with very low loaded runout off noses, even with cases exhibiting high thickness variances.
If these cases are put through heavy sizing cycles, then runout will still grow with each cycle. But, if the gun is shooting good enough with it, well then that pretty much trumps all else.

You are 100% correct. My answer was abbreviated and I was really leaning more towards continuing to experiment further. And of course my feelings that the newer brass is not what the older stuff was. (Lapua is probably the exception.) I also conveniently overlooked the fact that the rifle is not yet constructed never mind fired.

 

[TrxR]

Thanks guys. One more question though. Which is a prefered way to measure your neck thickness? A good Ball mic if so which one or what about a good fixture with a ground pin and a dial indicator.

Something like this.

Thanks

 

[CatShooter]

Thanks guys. One more question though. Which is a prefered way to measure your neck thickness? A good Ball mic if so which one or what about a good fixture with a ground pin and a dial indicator.

Something like this.

Thanks

I use both and both work!

 

[mikecr]

Forget any with a dial indicator.
Use a BALL MIC

 

[TrxR]

mikecr: What are the disadvantages of anything with a dial indicator.


and is that the sinclair unit in the picture?

 

[mikecr]

I have tested & compared both methods together.
The post, rather than ball, produces bad readings in unturned necks, -because this brass thickness steadily increases from mouths to webs.
A ball provides a contact point and is more accurate, barring any clutch issue.

Yes, the mic pictured is one from Sinclair. I made/installed the case stop.