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Just read an article in Handloader about partially sizing revolver cases. I could see doing this because of the minimum dimensions that Carbide resizers size the case down to in effect, the case is laying on the bottom of the chamber. Obviously, cases would have to be full length resized eventually because the would get harder to chamber with each firing.

Anybody try this or this really "a solution to a problem that doesn't exist".


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I like the idea, but the article doesn't mention how much of the case should be sized. I've read about partial sizing handgun cases before but nobody seems to want to tell you what "partial" means. Sounds like it's a guesstimate and I'm not much on that.

Hopefully somebody here has some more information
 

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In practice this works pretty well, provided that you haven't been running full tilt magnum pressure loads in your revolver.... as chambering can becom difficult.

However, if running light to moderate pressure loads it has some merits.  This partial sizing must size the case at least to the point on the case where the bottom of the seated bullet would be.  This insures proper neck tension on the bullet for uniform bullet pull and start pressure.

I loaded lots of ammo like this using a lyman tong tool in days gone by, and it was first rate ammo!   It's been years since I played with this technique on straight-walled handgun cartridges, but in some applications, it does have its place.

Interesting to revisit the past, and the ideas we have put upon shelves... some things once again become fresh!

God Bless,

Marshall
 

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I thought about this process for much to long before i tried it just last month.Theres lots more testing to be done but heres what i have so far. DW 445SM 8in.barrel   Starline brass,Fed150 primer,Sierra 250gr sil bullet,AA1680 powder. Useing cases from my last outing but not resized, i punched out spent primers with tool from Lee Loader kit.Than using standard 44mag.carbide die i sized case down just enough to seat for bullet length.By the way have you ever noticed how nice your brass fits the chamber after its fired? Real nice huh! Using Sierra manual as a guide they list 38.7 gr/AA1680as max for the 250fpj at 1600fps.I started at 35gr + got 1480 fps avg. Going to 37gr i got 1560fps avg. Going to 38gr i got 1640fps avg.This is almost 1gr.less powder than Serria listed as max.but i was getting more velocity + the cases showed absoluty no resistince to sticking.Using this methold i think i could safely reach 1700+fps in my gun.I would think this would result in more accurate ammo for sure, something i didn't check, because this gun shoots [email protected] with regular loads. There is a lot less working of the brass thats for sure! I notice when full length resizing when i get at published max, cases get sticky! Now i know this little test dont prove much but i will continue. There is definitely something there if you want more speed without overloading,which i think there's a lot of going on! By the way these cases drop right back in the chambers.     Royce
 

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Sounds like a reasonable idea to me, although I have not tried it.

To understand why this works, you need to understand that brass (like most any material) stretches under stress in two ways. These are called 'elastic deformation,' which is reversible like stretching a rubber band, and 'plastic deformation,' which is permanent like swaging a lead bullet. If the amount of deformation (expansion) due to firing is small, i.e. with a 'tight' chamber, most of the expansion will be elastic. The looser the chamber, the more plastic (permanent) deformation you will get. Remember that with almost any reasonable load, the pressures will be high enough to force the brass out in full contact with the chamber wall, sealing the chamber and acting as a gasket. This is one of the primary functions of the brass.

With handguns having 'sloppy' chambers relative to the unfired case diameter, you will get more plastic deformation. Provided that you are not loading above normal working pressures, you will always get some elastic deformation, so the brass will spring back some after it is fired. It will spring back to the dimensions set by its elastic deformation limit.

Once the brass has been fired, and the bottom of the case not sized, when it is fired again IN THE SAME GUN that lower portion of the case will not undergo significant additional plastic deformation, i.e. it will spring back to pretty much the same as-fired dimension. Repeated sizing and firing of brass causes it to work harden, and this eventually causes failure. The necks of many cases are annealed (which softens and intentionally weakens the brass) so they can stand more sizing-expansion cycles than the rest of the case.

The IN THE SAME GUN thing is important, since the dimensions of the fire-formed and unsized brass will often exceed SAAMI limits, particularly if your chambers are loose. This is not a problem if you are re-firing in the same gun, but it can be if you want to use the ammo in a different weapon. I think that Marshall said something on this site about how the Lee Loader (for example) only resizes the case neck, and therefore is recommended only for use to reload for the same weapon.

According to an article I read by John Linebaugh on the sixgunner website, for the 45 Colt the problem of sloppy chambers is quite prevalent and is the result of two factors: the chambers are often made at the upper end of the SAAMI limits to ease chambering of cartridges, and current-production brass is at the lower end of its dimensional limit. This results in excessive expansion, and therefore shortened case life. It is an interesting article, "The 45 Colt: Dissolving the Myth, Discovering the Potential." You can find the article at: http://www.sixgunner.com/linebaugh/dissolving.htm.
 

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In response to the observations and questions posted on this thread I gave a quick test yesterday in the .44 Magnum to neck sizing only in a couple of revolvers.

I loaded a very proven load that has an extensive track record, and well documented performance in my revolvers.

BTB .432"-280g WFNGC/12.5g AA #5/WLPP/Rem Brass/1060 fps 5.5" Bbl.

This load is very comfortable to shoot, and superbly consistant in its chronographed  results over time  (single digit ES)  No, this is not a powerhouse load, but much fun to shoot, and it does not shoot to the same point of aim as my serious hunting loads.  It was fairly accurate in my Blued SBH 6" gun, but woefully inaccurate in my 5.5" SS Bisquero.

I loaded 50 rounds, only neck sizing them, and slightly flaring the case to readily start the bullets.   They were crimped in my usual fashion using a Redding Profile crimp die.   The only difference between this load and my other tests with this bullet/load combination was the fact that these loads were only neck sized, instead of full-length sized as in the past.

In the SBH 6" gun, performance was on a par, it shot into about 1.7" at 30 yards off the bench.  Not much difference than with full-length sized cases.

However, in the Bisquero, with somewhat generous chamber dimensions, the story was entirely different.  In this gun, this particular load has never shot better than 3.4", and after looking over nearly two dozen targets, fired over several sessions in the past, the average target group with this load was about 4.1".

Now, shooting this load, with neck sized cases in the same Bisquero, the first target came in at 1.12"!  I fired all fifty rounds through the gun, with ten rounds per target.  the average group was 1.62", while the smallest was .73" center to center discounting two called fliers!  Yes, I was having a good day behind the bench, but the differences with this load were staggering when compared to full length sized case loads.  

Now, just to make sure that this test wasnt' just due to a great day behind the gun, or perhaps better bore conditioning, or some other factor, I went up to the shop and loaded 25 rounds, with the powder measure set the same, and all loading dies set the same, except for once again full-length sizing of the cases.   Down to the shop range again, and test... two ten round groups with an average of 3.72" center to center with discounted fliers penciled out of the equation.

Yes, in some guns, I would say that there are some applications where neck sizing only is a decided advantage!  Note too, that the loaded rounds slipped right into the gun with no hesitation at all, but too these cases had previously been fired in the same revolvers... a must when neck sizing only.

I thought you folks might like to hear of my findings over the weekend.

God Bless,

Marshall  
 

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I'm using a Lee loader now for my 44. It is working fine but my groups are not good. Great at 10 yds. Clover leaf stuff but move to 25yds and it's all over. I think that's operator error. Anyway the neck sizing is going fine but as previously said I am shooting light target loads. Want to make my brass last.
 
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