Logically thinking I guess that would likely happen..
One more tip.
- Thread starter jamesdmock
- Start date
Cartridge wedging would be affected by shoulder angle.
I've seen this notion extended to belief that headspacing of the case actually changes with primer striking. I'm sure again that shoulder angle is a factor here, and in this scenario the shoulder area and striking forces would also be factors. My testing of it with 30deg(6br, 6xc), 35deg(26wssm imp), and 23deg(223rem) shoulders show no change to shoulders with mere firing of primers in empty cases. Takes a minute to try it yourself.
But case by case, happening or not, there is still no predicting centering with bananas loaded (set into tension) in straight chambers. And on firing, bananas would shift a lot & possibly slap chamber walls differently enough to matter. If you lay a thumb on the action tang, you can throw shots via similar altering of vibrations. I've seen lugs out of abutment contact cause chronic flyers. Doesn't take much.
So I think FL sized ammo & larger chamber/neck clearances lead to good results partially because this is a forgiving condition for crooked ammo. On the flip side, I've set conditions so tight as to be coined 'fitted', and observe this shooting very good -provided the ammo is truly straight.
Truly straight is not concentric ammo with high TIR.
Straight measures low in TIR off loaded bullet exposed bearing, on a v-block runout gage. With this, the ammo will also measure concentric on any neck bender.
This is best.
On making of straight ammo, that would be another thread
I've seen this notion extended to belief that headspacing of the case actually changes with primer striking. I'm sure again that shoulder angle is a factor here, and in this scenario the shoulder area and striking forces would also be factors. My testing of it with 30deg(6br, 6xc), 35deg(26wssm imp), and 23deg(223rem) shoulders show no change to shoulders with mere firing of primers in empty cases. Takes a minute to try it yourself.
But case by case, happening or not, there is still no predicting centering with bananas loaded (set into tension) in straight chambers. And on firing, bananas would shift a lot & possibly slap chamber walls differently enough to matter. If you lay a thumb on the action tang, you can throw shots via similar altering of vibrations. I've seen lugs out of abutment contact cause chronic flyers. Doesn't take much.
So I think FL sized ammo & larger chamber/neck clearances lead to good results partially because this is a forgiving condition for crooked ammo. On the flip side, I've set conditions so tight as to be coined 'fitted', and observe this shooting very good -provided the ammo is truly straight.
Truly straight is not concentric ammo with high TIR.
Straight measures low in TIR off loaded bullet exposed bearing, on a v-block runout gage. With this, the ammo will also measure concentric on any neck bender.
This is best.
On making of straight ammo, that would be another thread
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James, when you talk run out .001 is this total ? I was check some I loaded and Total run out was .0005 so it is out .00025..... Jim
I normally look for .001 or less total runout (or .0005) on each side. Occasionally, I will straighten those with .002 or .oo1 on each side. My preference, or course is no runout, but that doesn't happen often in the real world. I have a friend who built his own runout gage and it is not accurate. He fools himself by operating it in a method that minimizes apparent runout and states that his loaded rounds don' have runout. The device has a chamber cut for a particular cartridge and a gage attached to the bottom. He turns the round in the chamber (which has some clearance) and the gage tends to push the round at the bullet to minimize recorded runout. He does load quality ammo with little runout, but his device does not give him the absolute truth. Good shooting...James
Just found a problem. My K&M expanding mandrel was out of round. Don't know if it's always been that way or just wear from several years of use. It was a full .0005 thousandths off in diameter. I trued it up to less than .0001" (not measurable with a micrometer), and polished it with 2000 grit sandpaper. I also checked the pilot and it's as it should be.
BoydAllen
Gold $$ Contributor
So many seem to think that their imaginings about what takes place are accurate enough to substitute for experience. I have a H&H concentricity gauge, and although I have only used it for short range benchrest, short bullet ammo, I can tell some of you that your imaginings are not reality. Some bullets can be moved quite easily. Others are resistant past a certain point. I mostly shoot flat base custom bullets that have pressure rings. I am told that BTs can also have this feature. When a bullet is seated, the pressure ring acts as an expander to the point where it is seated, opening up the neck very slightly. That is why you can feel a difference if you pull bullets and reload the case without resizing. This slightly enlarged portion at the front of the neck (after bullet seating) allows the pressure ring to act like a limited range ball and socket joint in the neck, and within a limited range a bullet that has been seated slightly off in a straight case can be moved to a more concentric orientation. On the other hand if the case itself is crooked, then when straightening is attempted one can feel the bullet hit a hard stop that is springy and quite resilient. Of course the only way that you would know any of this is from actual experience with the tool in question, something that many commentators seem to lack. One more thing, this gauge is only $139 + $8 shipping. If you didn't like it I am sure that you could recover most of that reselling it. It is very well made, and adaptable to a wide variety of calibers, from relatively small to large magnum. Certainly, I believe that the best use for concentricity gauges is to detect die issues, but once you have those sorted, this unit will allow you to tweak what little crookedness remains with relative ease. One time I took mine to a short range benchrest match and straightened every round after loading, without significant delay. When I was finished there was a short line of competitors who asked me to check their rounds to see what their tools were producing. After that I bought a better fitting arbor press type seater and with that was able to seat my bullets to a satisfactory degree of straightness. Finally, if your case necks are crooked you need to find out what is making them that way and fix it, but if you are dealing with slight seating errors in straight brass small corrections can be made.
Boyd, you stated well (as usual) what I should have stated. Many have the idea that in straightening, we are prying the bullet over with great force. That is not the case for me. Normally I just tap the lever on the H&H tool to correct a round that is SLIGHTLY crooked. Actually, if one marks bullets that are straightened; shoots them and resizes, he may find that the next time it doesn't need any straightening. Good shooting....James
For a while I had both H&H and Sinclair bearing v-block. It was clear as day that ammo adjusted to lowest readings in the H&H had more/separate runout as indicated on the Sinclair.
This is because you can center nearly any shape(including bananas) to a concentric axis. Then, if you desire to read a lowest value (of anything), all you need do is indicate nearest a pinned axis point while floating the furthest axis point, which is exactly what the H&H does. It pins the bullet end and indicates very near that fixed condition.
On crooked ammo picture a rigid jump rope arch with handles pinned in fixed locations on each side.
If you wanted to see the maximum displacement of it's arch, you would measure in the middle as it turns. NOT near one of the handles.
Another way to see maximum displacement of this arch is to pin the middle to fixed location, and measure one end. This is runout/ v-block measure.
Why would neck/bullet benders be designed to conceal runout?
Well for one, you can't straighten ammo with them. Go back & forth between measurement methods(as I have) and you will see this. So, you would meet with futility in it's function if reading total runout as well.
My point is, you can make bananas read low on an H&H, and I suppose you've reached a concentric condition there. But your chamber is more like a v-block.
And, if you make straight ammo as measured on a v-block, it is also concentric.
So it makes more sense to just do that.
H&H, low/high:
V-block, low/high:
This is because you can center nearly any shape(including bananas) to a concentric axis. Then, if you desire to read a lowest value (of anything), all you need do is indicate nearest a pinned axis point while floating the furthest axis point, which is exactly what the H&H does. It pins the bullet end and indicates very near that fixed condition.
On crooked ammo picture a rigid jump rope arch with handles pinned in fixed locations on each side.
If you wanted to see the maximum displacement of it's arch, you would measure in the middle as it turns. NOT near one of the handles.
Another way to see maximum displacement of this arch is to pin the middle to fixed location, and measure one end. This is runout/ v-block measure.
Why would neck/bullet benders be designed to conceal runout?
Well for one, you can't straighten ammo with them. Go back & forth between measurement methods(as I have) and you will see this. So, you would meet with futility in it's function if reading total runout as well.
My point is, you can make bananas read low on an H&H, and I suppose you've reached a concentric condition there. But your chamber is more like a v-block.
And, if you make straight ammo as measured on a v-block, it is also concentric.
So it makes more sense to just do that.
H&H, low/high:
V-block, low/high:
butchlambert
Site $$ Sponsor
I use a custom seating die made with my chambering reamer. I don't have concentricity problems.
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