Unusual reloading problem

[falsetile]

I am new to reloading, and I am using RCBS Competition Dies in an RCBS Rock Chucker SS press.

When I measure my fireformed 22-250 brass in the mic, it comes out to a very consistent 44. Now, when I try to FL resize, and measure again, it consistently reads 46.

In attempting to bump the shoulder back 0.002", the mic gauge is saying that it is having the opposite effect, expanding by 0.002". I can't figure out how this is even physically possible, and I'm sure that I am reading the micrometer right. Any ideas?

 

[Linefinder]

Your fireformed brass has expanded in diameter. When you FL size your fired case, it is squeezing the diameter back down to "nominal" size. This "expanded diameter" has to go somewhere, so it flows forward.

What you are seeing is normal when FL sizing fireformed cases.

Mike

 

[falsetile]

Thanks for the response. I was under the assumption that all the brass flowed to the mouth.

So what I am seeing is that my chamber is 0.002" shorter than SAAMI?

 

[falsetile]

So just to clarify, to "bump the shoulder back" is to shorten the head space by a given amount, say 0.002", right?

In FL resizing my brass, I am constricting the diameter and the shoulder moves forward, as the micrometer shows. Now, should my goal then be to decrease the headspace by 0.002" of the original micrometer reading?

The only way I can think to do this is to screw the die in further, but it is already touching the top of the case holder...

 

[savet06]

Just wanted to put in that this is a great post/thread. I have just had my first custom rig built, and this information came at a very opportune time. So much good info here.
thanks, guys.
Mike

 

[BoydAllen]

Falsetile,
As you adjust a FL die closer to the shell holder, you will reach a point where the shoulder of the case does not yet touch the shoulder of the die, but the diameter of body at the shoulder of the case is sized smaller. Without the shoulder of the case being restrained by the die the shoulder pops out into the available space.,Imagine an isosceles triangle, where the base is shortened while the two equal sides remain the same length. It would get taller.)If you continue to screw the die down toward the shell holder, you will eventually reach the point where the shoulder of the die makes contact and further adjustment will show a decrease in case "headspace". What can fool the novice reloader is that even though a die is adjusted to touch the shell holder before a case is inserted, the additional pressure on the press linkage of actually sizing a case will cause a gap between die and shell holder at the top of the stroke when a case is actually being sized. On my .220 Swift, for example, this gap allows the die to be lowered an additional .006,too much for proper bump). I would suggest that you keep adjusting your die downward and check for shoulder bump as you do so. At some point, if die and chamber are within SAAMI spec., you should get the amount of bump that you seek. Let us know if this works for you.

 

[falsetile]

Boyd, that was very informative. I went back to my press and tried it again, still no dice. The press bottoms out on the die before it will ever bump the shoulder back. It's almost as if my shell holder is too thick, but I don't see how because I'm using the prescribed shell holder for my dies: RCBS Competition Dies, and RCBS #3 case holder for 22-250.

Also, I noticed that a very distinguishable line occurs about 1/4" up from the case head, where the brass goes from shiney to dull after FL resizing; it looks as if the compression "stops" there. Is it supposed to continue the whole way down to where the rim starts? If so, is it possible that I somehow have a die that is cut too deep?

 

[skipper]

Just a suggestion, but, Redding makes a set of shell holders with varying heights. You can raise the case, with respect to the top of the shell holder, in .002" increments. This will allow you to set the die to touch the shell holder and still achieve the headspace you want.

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=359546&t=11082005

 

[falsetile]

Thanks to all for the great feedback on this thread -- I think I have diagnosed the problem now. My fired brass reads 45 on the mic originally, then when I adjust the die to just 'kiss' the top of the holder, it grows to 48. Now if I keep adjusting the die down, I can get it back to 45, where it bottoms out on me. I think the key will be to polish 0.002-0.003" off my shell holder, and I'll be in business.

 

[BoydAllen]

Let's go slow here. Brass does not usually reach the full length of the chamber until it has been fired, neck sized only,with a stout load, two or three times. Why don't you check your sized brass for fit in the chamber. It may be that it works just fine.If it does, back off your sizer for a thousandth longer "headspace" and check again. I always start from a reference case that has been neck sized and fired till the case "headspace" does not grow any longer. One common error is to mistake brass tightness that is at the back of the case for tightness at the shoulder that requires a bump.

Any time that you get a bright line just above the head, on a case, you need to check to see if you have what is called an incipient separation. You can do this by straightening a large paperclip and putting a 1/8" long right angled bend at one end. Use this tool to feel for a groove in the sidewall just above the bottom of the inside of the case. If you feel anything of the sort, you might want to section the case lengthwise to be able to better see the problem before you throw the case, and probably that batch of cases, away.

 

[falsetile]

There again, I had no idea it took multiple firings to get the headspace to reach its max length. The brass in question is once-fired Winchester brass, and the load was also very conservative,90% max, bullets well back from the lands).

As for the line, it is not a 'line' actually, it is a border between a shiney area,near the head) and a dull area,forward of the head) that occurs after I take the brass out of the FL resizer. My best guess is that it is showing where the brass starts getting squeezed and worked forward, and thus looks a bit more dull.

My main concern here is not one of chambering, as the once-fired cases chamber just fine, but it is to acheive neck concentricity from the FL resize.

Does FL resizing have anything to do with chamber pressure, or is in mainly for feeding/concentricity?

 

[BoydAllen]

If your FL die has fixed inside diameter in the neck,not a bushing die) and an expander ball, it may actually be hurting your concentricity. Typical one piece,non-bushing)FL dies over size the neck and then drag an expander ball back through it to get to the desired pre bullet seating neck ID. The force required to overcome the friction of the expander being pulled through the neck is enough to cause the shoulder of the case to be pulled slightly out of shape, and since the brass does not give the same all the way around, the neck becomes cocked in the process. With a custom one piece, or bushing type FL die, the amount of expanding that needs to be done, assuming unturned necks, is minimal, and if the chamber is neck ID is small enough so that necks can be turned to uniform their thickness, the expander is usually dispensed with altogether. If you are using a FL die to straighten unfired brass, about all you are doing is working on the neck. In this case, make sure the insides of the necks are lubed and the expander polished, but not so much as to change its diameter. Also, pull the expander through the necks slowly, since this reduces the peak pull on the shoulder.

 

[falsetile]

I do have a fixed neck, non-bushing style die, but I have removed the expander ball from it altogether. I agree with you on the adverse effects on concentricity from those expander balls.

What I am using now in place of the expander ball is a Sinclair Expander Body, with the same mandrel that I used to neck turn the cases before fire forming them. I lube the inside of the necks lightly with a Q-Tip, then use the press with the expander body screwed in to expand the necks enough to try to uniform the ID and neck tension some after FL resizing. There is, however, some longitudinal pressure applied the the case as I push the neck on to the mandrel and pull it back off again. I assume it is not as much of a problem as using the floating expander ball, because the expander body/mandrel is completely rigid.

I have yet to do a lot of neck concentricity gauging with this setup, but for now I think it helps more than just using the ball.

Should I consider using a bushing-style die or custom die in the future?

 

[BoydAllen]

Your assumption may be incorrect,about the Sinclair expander. If you are processing a lot of brass, for a varmint rifle, in a situation where each case may not be fired that many times, you may want to look into using a Lee Collet Die to neck size, and a body die for that part of the case, when fit considerations dictate. BTW the Sinclair concentricity gage will allow you to actually measure what is going on. Without the right tool, you are "flying blind". Parenthetically, I have often said that the consequences of lending a concentricity gage to a reloader that is at the point of wanting to take it to a new level, are consternation and expense. Nevertheless, you "need" one.

 

[mmcauliffe]

Also, I noticed that a very distinguishable line occurs about 1/4" up from the case head, where the brass goes from shiny to dull after FL resizing; it looks as if the compression "stops" there. Is it supposed to continue the whole way down to where the rim starts? If so, is it possible that I somehow have a die that is cut too deep?

I think I am way too new at this to offer any real advise, I am watching this thread with great interest.

I use a bushing type Redding Comp "S" die, RCBS #3 shell holder for my 22-250 and it does EXACTLY the same "ring thing". It looks like it's some sort of transition point where the die stopped making contact with the casing. I don't believe it's a safety issue, but that is something you need to verify on your own. It's happening with all my brass, both Remington & Federal and I have been fairly conservative with the loads.

I also thought that my shell holder was too thick or there was something wrong with my die.

I used a dry marker and marked the neck & shoulder of the casing,this is not easy with the lube) to see where I was making contact. I could easily see how far down the bushing was making it's way down the neck buy how much of the marker was being rubbed off. I kept adjusting the die down ever so slightly until I got the desired bump I wanted, about .002. Using the Stoney Point [Hordany) head space gage I finally got the desired results...or so I thought until now! I get a very consistent 3.5685 -/+.0005 but NOW I think I may be inadvertently FL sizing!?! How do you know?

 

[BoydAllen]

Actually, when I fire new 6PPC cases, and pressures that are not mild, it takes at least two firings,not counting the one that formed the case) for the "headspace" of the brass to reach its maximum vlaue. I determine this with the use of a short piece of barrel that has been chambered,with my reamer, to the end of the shoulder, and a dial caliper. I use this same setup to check for die adjustment when I change to a different group of cases that may be more or less work hardened, and therefore require a slightly different die setting. Expansion mechanics aside, what I find useful is to determine the longest headspace that a particular rifle and barrel will produce, and gage my bump in relation to that. The reason that I do it this way is that, years ago, I determined that bumping my .220 Swift from a once fired headspace length was detrimental to brass life, producing a bright ring that I could feel on the inside of the case, with a bent paper clip. On the other hand, simply FL sizing to the same headspace as a once fired case, worked well, with no bright ring, or fit problems. Since that time, I have either sized to match a once fired case, when that was all that was available, or when loading at the range facilitates it, fired one case several times, with only neck sizing, till the headspace stabilized, to create a case from which to obtain a reference measurement for that barrel.

 

[BoydAllen]

Of course it hits the shoulder the first time. You are correct about the spring back. Another issue is the duration of the pressure. Take a work hardened case and run it through a FL die quickly, with no pause at the top of the stroke. Measure its headspace. Now size another case from the same batch, fired the same number of times,hopefully equally work hardened), and pause at the top of the stroke for ten seconds, and then measure that case, and compare it to the first. Beyond that do two for the same dwell time at the top of the stroke, but lube one just enough not to have it stick in the die, and leave a heavy coat of lube on the other, and compare. Now you can see that if different degrees of work hardening, different top of stroke dwell times, and differing amounts of lube all have an effect on the headspace result when FL sizing, that the subject just may be a little more complicated than most of us initially thought that it was in the old "run it down till it touches the shell holder" days. Getting uniform results takes some planning.

 

[falsetile]

44 was just a relative measurement on the micrometer, with no absolute meaning.

The rifle I am loading for is a Remington XR-100 in 22-250. It is sounding like I need to just get a neck-sizing die until I get feeding problems and then worry about FL resizing. I was really going off of Froggy's article where he says "Bumping the shoulder back 0.002" is the key to concentricity." Bullet concentricity as well as seating depth are two things that I find myself obsessing over,after case uniforming) again and again. I need to do some more neck concentricity gauging with my fireformed cases before I jump to any more conclusions, however.

 

[BoydAllen]

My factory barreled varmint rifles all will shoot well under half inch, and they respond to careful reloading. Many of the things we do in Benchrest work to improve the performance of ordinary rifles. Yes, you can wear out a barrel without FL sizing, but not with hot loads and a reasonable bolt lift. Do you think that all Benchrest shooters started out on custom 6PPCs? My first rifle was a 788 in .308 with a 4X Tasco scope. My first reloads were produced with a Lee Loader. Yes, SAAMI chambers are larger, but even so, more carefully crafted ammunition shoots better in them. The good thing about hobbies is that we get to do them our way. Some of us like the little details. Some do not. BTW standard expander ball type, non bushing, neck dies are generally the work of trolls, in terms of the straightness of the ammunition that they produce. Lee Collet dies are much better in that respect, and are cheap, and easy to use.