Neck dimension

[NezRongero]

I am in the process of setting up a Palma gun in 223 Remington. To build it I will spec out my own reamer or copy a known successful version specific to the Berger 90 VLDs. For a start I am thinking about using the Wylde reamer for the basis, and throat it for the long 90 VLDs.

Looking at the Wylde reamer print, the neck has a very generous tapered neck, 0.2568 at the base and ends at 0.2258. The reamer works great for service rifle application, but for a match rifle, maybe I could do better. Looking at my sample dummy rounds I am reading 0.2470. I really do not want to overwork the necks and kill them early. Though the intended purpose of the rifle is for sling shooting, the rounds will be single loaded and no restriction for loaded ammo length. I am looking for some input from the bench rest perspective in terms of ultimate accuracy. I seem to recall there has been some discussion in the past as to what appears to be optimum neck for a given loaded necks for some calibers, but I could not put my finger on them.

What would you guys recommend I should spec the neck diameter to be, based on the loaded round neck diameter of 0.2470? I do intend to turn the necks to achieve consistent neck diameter. And, I am not totally opposed to turning the necks even thinner if someone would recommend a certain proven spec.

It would be easier to build a Palma gun in .308, but my shoulder with Arthritis would be happier with the lower recoil and my wife's check book would be even happier with the lower cost of feeding a 223 over a 308.

Thanks in advance.

nez rongero

 

[alinwa]

From a Benchrest perspective the necks must be parallel and between .002 and .003 TOTAL clearance over your loaded round. Incidentally setting up for clearance on un-turned brass and then turning the necks "to clean them up" will always result in a net loss of accuracy. You must make the turn/no-turn decision FIRST, then spec your neck dimension.


opinionby





al

 

[NezRongero]

From a Benchrest perspective the necks must be parallel and between .002 and .003 TOTAL clearance over your loaded round. Incidentally setting up for clearance on un-turned brass and then turning the necks "to clean them up" will always result in a net loss of accuracy. You must make the turn/no-turn decision FIRST, then spec your neck dimension.

opinionby

al

Thank you for the input. Will do as suggested.

 

[Charles E]

From a Benchrest perspective the necks must be parallel ...

From a modern, easy to do perspective, this is holy writ, and likely good advice, However, over a longer period of time, a number of people not to be quickly dismissed have advocated a slight taper to the neck -- Ferris Pindell, TJ Jackson, Hugh Henriksen, etc.

It isn't so much "a number." And if you're going to pick a number, it would be closer to a rate of .001 per inch for the neck, not .001 regardless of neck length.

Why anyone does it gets into (1) how sizing brass in dies affects springback, (2) the "support" of the neck in the case as you near the shoulder, and (3) the release of the bullet. And oh, yes, there is some interaction.

There are several ways to do this: you can have the taper in the chamber, or you can cut it in the neck, as Pindell and Jackson did with their neck turners.

But you also have to consider how a modern bushing die works -- the final pass (indeed, the only pass) is on the outside of the neck. If you limit yourself to bushing dies, the only taper should be to offset a slight difference in springback at the shoulder end versus the mouth. On the other hand, if your final sizing pass is over a mandrel or an expander ball, the final pass is on the inside of the neck. A little less to worry about here, and (probably) a better neck, given the various things we ask it to do -- hold the bullet in proper alignment to the bore, release the bullet, and seal the chamber.

By the way, just because you use a mandrel (preferred, at least by me) or expander ball, there is no reason to overwork the brass. Size it down only enough so the expanding operation can take place -- i.e., essentially an expander ball maybe .001 larger than the "bushing" (or whatever you use to size the neck down).

Working this all out gets a bit complicated, and you either add a step in reloading or need custom dies -- often both. For Highpower & the number of rounds needed, I don't think it's worth it. Improvements (if any) are too small, given that 2 MOA 10 ring.

Incidentally setting up for clearance on un-turned brass and then turning the necks "to clean them up" will always result in a net loss of accuracy. You must make the turn/no-turn decision FIRST, then spec your neck dimension.

Sorta, kinda. I'd buy the brass first -- maybe 500 pieces, turn the minimum amount off until you get a 90+ percent cleanup with whatever percentage yield you want for cases.

Then specify your chambering and die reamers.

Well, you did ask how an anal, compulsive benchrest shooter would think about the issue... Again, I wouldn't do it with a 2 MOA 10-ring and 1 MOA x-ring.

 

[John S]

I would buy all the best brass you will need and have a NO-TURN reamer made to match with the .002 - .003 clearance as recommended.

A 90 grain .223. Wild!

 

[Mike Bryant]

I miked some Georgia Arms .223 ammo that uses Lake City brass and had neck diameters in the .247" to .248" range. When I built my AR-15, I chambered it with a .250" neck with .020" freebore length to match the Georgia Arms canned ammo and has worked well with their 55 gr. Hornady Vmax's and their 69 gr. MK's. I guess you'll be shooting yours in a bolt gun. The way I determine freebore length is to seat a bullet where you want it. Take a micrometer and set it at .001" smaller than bullet diameter, slide the mike down the seated bullet and then measure from the end of the neck to where the front edge of the micrometer stops on the bullet. That will be what I specify for the freebore length.

 

[NezRongero]

There are several ways to do this: you can have the taper in the chamber, or you can cut it in the neck, as Pindell and Jackson did with their neck turners.

Working this all out gets a bit complicated, and you either add a step in reloading or need custom dies -- often both. For Highpower & the number of rounds needed, I don't think it's worth it. Improvements (if any) are too small, given that 2 MOA 10 ring.

Sorta, kinda. I'd buy the brass first -- maybe 500 pieces, turn the minimum amount off until you get a 90+ percent cleanup with whatever percentage yield you want for cases. Then specify your chambering and die reamers.

Well, you did ask how an anal, compulsive benchrest shooter would think about the issue... Again, I wouldn't do it with a 2 MOA 10-ring and 1 MOA x-ring.

Charles,

All the points from you and the other responders are all well taken for my education. Thank you for the input. As far as brass prepping, I got the time and the equipment to do it. I am retired, got more time than money.

It has been awhile since I was in the bench rest thing. You mentioned TJ on how he preps brass. I was a young guy running around with TJ and Frank Wilson shooting bench rest in the 80s till I found high power later on and has been in it. Back then I spent many nights in TJ's garage watching him fire form and turn the necks on my PPC cases, but at that time I was not paying that much attention to the nth detail TJ went through making the PPC brass. He fired the brass first, made the cut the inside then outside, fired them again and made the final cut, then test fit them, measured and did the final finish with steel wool. He stressed the point being prefect.

Anal and compulsive bench rest shooters blaze the trail in precision shooting....


nez

 

[Charles E]

OK, nez, I think you have two good choices. Which costs more depends on who does the reamer & what they charge, and the dies.

The most straightforward way is a method Boyd Allen has written about more than once on BR Central. Done it a time or two myself. You pick a good commercial die, like a Redding, or Forester, or Maybe a Hornady (I'm not going to get into who makes the "best" commercial dies), and you ask one of the reamer makers to make a chamber reamer to fit that die.

Or, depending on the reamer maker, you could ask if they have on shelf (i.e., not at a custom reamer price) a reamer that in their opinion matches a certain commercial die. So, PT&G charges the same, pretty much, for all reamers, "custom" or not. This is not a recommendation, but I'd think PTG has their usual kinks worked out for a reamer they'd worked up to match a die. Dave Manson and JGS both have two-tiered pricing. You'd have to call & ask. What's custom and what isn't, and how much more custom is.

Then you take your chances on the brass being a good fit to the die, and often times it is.

The "perfect" way is to get the brass first. Like Mike Bryant, the best brass I ever got for the .223 was Military. Better than Lapua, far as that goes. But we're into the real little things here, and there are always compromises.

The point is to pick a brand, and initially, get a sufficient quantity of cases. The good news is cases from a particular manufacturer do tend to stay the same over the years. But I've seen as much as .004 inch difference in base diameter between RWS and Lapua. Imagine what happens if you've specked the chamber reamer to be .004 over nominal case diameter...

Now you have the chambering reamer ground to match that virgin brass. You can get into another long argument over what dimensions for a chamber are right to "match" a case. I'm not going to get into that, either. If you want help with the decision, my answer would be to ask whoever you select to make the reamer.

Now you need a custom die, maybe, to match the chamber. And that, depending on who makes it, is going to cost significantly more than a commercial die.

But you get the idea, reamer-die and even virgin brass should all fit together, though there is some variance in thinking on what the chamber clearances should be.

I'd skip the tapered neck BTW, unless the die maker wants you to use that, or, if you get a TJ Jackson neck turning tool (man named Walker got all TJ's parts, & maybe still makes them. Think he worked for the physics instrument shop at the University of Texas. If you want his name & number, I'll look him up). But as I said, this means you should make an expander he last pass of your sizing routine. Really, I'd skip it.

So, homework is to call the reamer makers & find out what they got and what they recommend, and of course, what the various prices are. Then take a look at both commercial and custom dies, and their prices. Only after you know what you're going to do for the whole *system* do you actually place orders -- that is, spend money.

As far as the reloading end goes, that's as good as you can get. I can't tell you how to get a good barrel...

 

[Mike Bryant]

Charles,

All the points from you and the other responders are all well taken for my education. Thank you for the input. As far as brass prepping, I got the time and the equipment to do it. I am retired, got more time than money.

It has been awhile since I was in the bench rest thing. You mentioned TJ on how he preps brass. I was a young guy running around with TJ and Frank Wilson shooting bench rest in the 80s till I found high power later on and has been in it. Back then I spent many nights in TJ's garage watching him fire form and turn the necks on my PPC cases, but at that time I was not paying that much attention to the nth detail TJ went through making the PPC brass. He fired the brass first, made the cut the inside then outside, fired them again and made the final cut, then test fit them, measured and did the final finish with steel wool. He stressed the point being prefect.

Anal and compulsive bench rest shooters blaze the trail in precision shooting....


nez

Since you spent time around TJ, there probably wasn't any one any more particular about the nit picking aspects of shooting benchrest or building rifles that TJ. I know Frank well, but never knew TJ all that well although I shot with him some in the mid 80's.

 

[NezRongero]

Charles,

Thank you again for all the excellent input, invaluable. When I started high power, shooting across the course, as you mentioned 1 minute X ring and 2 minute 10 ring puts the burden on the shooter, just about any ammo is capable of cleans. With the Palma gun I have in mind, if the system were to come out precise enough I might shoot in in FTR on occasion, which I see the F class being bench rest on the ground. That half minute X ring is not very forgiving.

I have AJ Walker's number I will give him a shout, I totally forgot that he got some of TJ's stuff. Years ago AJ showed me how to bed my 700 switch barrel hunting rifle, I remember him using G-10 pillars and Devcon.

Over the years I lost track of all the stuff about precision shooting and how to make the rifles shoot bug holes, the ARs, being LEGGO guns, just about anyone can wrench one together and the finish product is about as good as it is going to get, assuming the package is based on a good barrel.


Mike,

You are right, TJ is about as anal as anyone I know, but he was strictly metal machining guy. I remember him saying he does not do any carpentry work, thus he does not bed any rifles. When I shot benchrest I was a poor young man with a young family, TJ pretty much supplied me a couple of barrel with the ones that did not shoot quite good enough for him after being "shot out." Shot out for him is more than pretty good for me, $50 barrels ready to screw on with a fresh chamber were not bad.


Thank y'all for all the input. I think I have a pretty good idea where to take this discussion.

 

[Boyd Allen]

If I may speak to the working from a factory die angle a bit, when I have done it, I have actually worked from sized brass FROM that die, much preferring brass that has seen a lot of firings and full length sizings, because it has more spring back, and will come out of the die a little larger than new brass. With that sized brass in hand, I measure the body, and order a reamer with the body clearances that I want. It has been my experience that you really don't need much clearance at all at the shoulder. The reason that I say this is that my main PPC die does not size the diameter of the shoulder at all. It is a Harrell Vari-Base die, with base inserts that vary by .001 to allow adjustment for different chambers. With it, I can bump the shoulders, size the back of the case, and size the neck with whatever size bushing I want. Recently I was given a barrel with a non standard PPC chamber that is .005 oversized at the shoulder, and this die did not touch that dimension. In any case, my point is that the feel of the bolt when chambering a sized case from this die would not tell you that the shoulder diameter had not been reduced, but it will if the base, or shoulder to head dimensions are tight. For this reason, for non field applications, I usually spec. the reamer shoulder at .0005 to .001 over the largest "experienced" sized case. If you take this approach, make sure that the cases that have been sized are smaller in diameter at the shoulder and just above the extractor groove than before sizing, so that you will really know what the die gives you. Recently, I ran into a situation where this was not the case, when measuring used 7mm WSM brass before and after sizing. Even though the die was a stock Redding type S FL, and the brass dimensions indicated that the body of the reamer for the chamber that it had been fired in seemed to indicate standard dimensions, the bases of the cases were only shined up a bit, but showed no reduction in size. I think that for this die, in a hunting rifle, I will spec the back of the reamer .001 larger just to give some clearance. The application is to be for hunting. One final point, never make chambers too close of a fit to the base dimension of an unfired case. This will only limit your maximum load more than it would otherwise be. You will get a tight bolt sooner than it would be with a little more clearance.

 

[NezRongero]

If I may speak to the working from a factory die angle a bit, when I have done it, I have actually worked from sized brass FROM that die, much preferring brass that has seen a lot of firings and full length sizings, because it has more spring back, and will come out of the die a little larger than new brass. With that sized brass in hand, I measure the body, and order a reamer with the body clearances that I want. It has been my experience that you really don't need much clearance at all at the shoulder. The reason that I say this is that my main PPC die does not size the diameter of the shoulder at all. It is a Harrell Vari-Base die, with base inserts that vary by .001 to allow adjustment for different chambers. With it, I can bump the shoulders, size the back of the case, and size the neck with whatever size bushing I want. Recently I was given a barrel with a non standard PPC chamber that is .005 oversized at the shoulder, and this die did not touch that dimension. In any case, my point is that the feel of the bolt when chambering a sized case from this die would not tell you that the shoulder diameter had not been reduced, but it will if the base, or shoulder to head dimensions are tight. For this reason, for non field applications, I usually spec. the reamer shoulder at .0005 to .001 over the largest "experienced" sized case. If you take this approach, make sure that the cases that have been sized are smaller in diameter at the shoulder and just above the extractor groove than before sizing, so that you will really know what the die gives you. Recently, I ran into a situation where this was not the case, when measuring used 7mm WSM brass before and after sizing. Even though the die was a stock Redding type S FL, and the brass dimensions indicated that the body of the reamer for the chamber that it had been fired in seemed to indicate standard dimensions, the bases of the cases were only shined up a bit, but showed no reduction in size. I think that for this die, in a hunting rifle, I will spec the back of the reamer .001 larger just to give some clearance. The application is to be for hunting. One final point, never make chambers too close of a fit to the base dimension of an unfired case. This will only limit your maximum load more than it would otherwise be. You will get a tight bolt sooner than it would be with a little more clearance.

Boyd,

Thank you.

I do have a few 223 factory sizing die I accumulated over the years, I will do what you detailed out. If all comes out fine I may not need to get a custom die for the chamber, the reamer cut to the sized brass should be plenty enough based on your approach. I am a retiree on a fix income, any way I can stretch the buck I am all ears.

nez