Resizing - FL, Partial, or Neck - early returns

6

603Country

New member
When I started reloading some 30 odd years ago, I full length sized everything. Later, based on what I had read, I went to Partial Resizing. Later on I went to neck sizing. Due to some discussions on this forum and some info from competition shooters, I found myself wondering if maybe Neck Sizing wasn't the absolute best way to go. So...about a month ago I decided to play with some reloads and see what case sizing method worked best for my 223 (1 in 9 twist). I had a pound of Varget and I bought some 69 gr Sierra HPBT Match bullets. I had no reloading history with that bullet, so I started working up loads. Using neck sized cases, I found a load that worked pretty good, though not as good as I had hoped or expected (a bit smaller than an inch). I tried a few minor powder charge tweaks, but that didn't improve things much. Today's objective was just to find a good load that I could use as base data to compare other sizing methods to. I now had something usable, and I hadn't killed the whole day. Hmmm...I have time to try a few different things, so I partial resized the same cases and shot slightly better groups. Then I FL sized those same cases and shot much better groups. I didn't do any measuring of groups, but most definitely the FL sized cases shot better. I really wasn't expecting that. This is just some early data, and probably doesn't really count as data. On Sunday I'll get serious. I plan to shoot a bunch of ammo that is FL sized, Partial Resized, and Neck sized (same cases) and then when I have the results as to which method shot better, I'll then use that method on random headstamp cases that have been trimmed but not otherwise prepped and I'll see how that compares to the prepped cases. It'll take days, but I'm really interested in how this turns out. If I get any useful data that I think you might want to see, I'll put in this same thread.

I should mention that the neck sizing die is a Redding, but is not a bushing type die.
 
R

rvdoc

New member
I am also interested in your findings. I wish I had the time to try this. Thanks for posting this and I will be watching for the results.
 
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loademwell

New member
WOW!!! Never expected that. I would have thought that the FL would have shot a tad bit worse. Very interested in knowing if what they say is true about neck size only. I read that it was more accurate, but how much more? Is it truly noticeable at a simple 200 yrd. shot?

thanks for doing this....
 
6

603Country

New member
There's been some debate on this subject on this forum as to what case sizing method gives the best accuracy, and I just decided that I'd run some tests of my own and see what happened. The little shooting that I've done so far really can't be considered part of the test since I was just looking for a good load with that bullet. And, as it stands, I really don't have a good enough load yet. I'll switch from Varget to the powder that shot so well behind my 65 grain Sierras (AA2230) and see how that goes. If I'm going to do this, I want an accurate load as a base for the test. I'm really interested in seeing how this comes out. I'm not sure how long this will take, but I'm not going to rush this. I'm retired and have plenty of time and my own 100 yard range.

And when the results are in, I'm not sure that it will prove much, since it's just one gun being shot by one guy using the reloading techniques of that one guy. And, the results might not even be conclusive. But, I want to know. And I"ll eventually take the testing results and try to apply them to another rifle (my most finicky rifle) and see if its accuracy improves.
 
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jwrowland77

New member
True but its still fairly interesting.

I just always figured if I load one way consistently, then I can adjust my sights/scope to that point and as long as I load the same way every time I should get the same results.

Saying all that though, I am interested in this to see if I might be over working my brass for no reason.
 
B

Brian Pfleuger

Moderator Emeritus
I'd really like to see the test done with a Lee collet neck die. Ordinary neck dies can pull the neck off center when the expander is pulled through. Adding a collet die to your test would compare it to both full-length and regular neck sizing.

Hey, you've got all the time and money right? Get it done!;):D
 
6

603Country

New member
Ok, Brian, I'll order a Lee Collet neck die. If I'm going to do this, I might as well do it right (to a point at least). I knew somebody would bring that up, which is why I mentioned that I didn't have a collet neck die. The truth is that, in addition to what I've already got scheduled, I've wondered just how much difference the collet die would make. I didn't want to spring for one of the real high dollar collet dies, but the Lee is pretty cheap (dollars, that is). Ok, I'm in.
 
B

Bart B.

New member
Ah, yes, again the issue arises. . .full length sizing versus any other way.

Before I make further posts on this thread, I first want to know what the OP's accuracy objectives are. For example, consider these two scenarios with the same set of components (case, primer, powder and bullet):

One is, you shoot ten 5-shot groups testing your reloads made with process and tools in method A and the groups range from 1/10 moa to 8/10ths moa.

The other is, you shoot ten 5-shot groups testing your reloads made with process and tools in method B and the groups range from 1/10 moa to 5/10ths moa.

That's 50 shots testing both methods comprising different tools and methods. Statistically, an excellent test.

Which tool and process method meets your accuracy objectives?

Note this thread has a close relative at:

http://thefiringline.com/forums/showthread.php?p=5306276
 
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F

F. Guffey

New member
Again, I use versatile full length sizer dies, what is the difference between my versatile full length sizer dies and full length sizer dies purchases and use by all other reloaders? No, it is not threads, both my versatile and dies used by others have threads. I believe it is about how the die is used, I use the compassion tool to the press, the feeler gage, I use the feeler gage to adjust the die off the shell holder, I size cases in length from the head of the case to the shoulder and by doing so I control the length of the case from the head of the case to its shoulder, I can progressively increase the length of the case from minimum length/full length to infinity or a more practical field reject length, as with my M1917 Eddystone with the .016” added between the bolt face to the shoulder of the chamber, progressively increase in thousandths as in .000.

And, I use the feeler gage to verify the adjustment.

F. Guffey
 
6

603Country

New member
No, Brian, you can't have a Ferrari (at least not from me). Mr Guffey, it sounds like you are partial resizing. BartB, yes this has been cussed and discussed prior to this, but this is something that I want to do just for me. Most of the reason is the difference between what I think (or did think) about case sizing and accuracy, versus my present thinking or wondering about it, which was modified by what you've said on the forum - it being best to just FL size. Undoubtedly you are far more qualified to say what works best, but I'm not the kind of guy that will just take somebody's word for it. I just have to see for myself. Just gotta. Plus that gives me a good reason to do a lot of shooting. Now maybe my gear won't allow me to come to a conclusion, leaving me with data that tells me nothing. But...what you've said in the past, combined with something that happened in some recent reloads for my 260, have shaken my belief in neck and partial resizing. I had some new 260 cases from Nosler. I prepped them, as I usually do, and decided to shoot them and fireform them and then neck them for later use. I loaded them up with my normal favorite load and shot some really great groups with what I consider to be a finicky rifle (real light, not floated or bedded). Then I took the newly fireformed cases and I COULD NOT shoot a group that was as good as the new cases had allowed. That shook my thinking up.

So now it's my desire (my personal need) to see what works best, or at least what's best for me. I'm going to use the same 50 cases (assuming that they last throughout the test) and shoot 5 shot groups with those cases resized in several ways until I think I have an answer. Unfortunately, the limitations of me and my rifle might cause me to come up with a lot of powder and bullets gone and no definitive answer. But...we'll see. And I'll order that collet die on Monday, if the local gunshop doesn't have one. I wonder what the final answer is going to be.

I'm not trying to prove anybody right or wrong, and I'm not trying to be argumentative. This is just one of those things that I need to work out for myself. I'm an engineer. I need data.
 
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Bart B.

New member
Engineer, check this data:

Nobody these days setting records in rifle matches uses Lee collet dies. They never ever did.

Full length bushing dies have been the thing to use for several years in benchrest and for decades in shoulder fired rifle matches.

And Sierra Bullets has been full length sizing all their cases used to test bullets for accuracy in benchrest quality rail guns with the very best match grade barrels with SAAMI spec chambers (or virtual copies thereof) and I doubt anyone shoots their stuff more accurate than they do.
 
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C

cw308

New member
I neck size only for years. Bolt action 308, fired formed cases hold the shape of the chamber. I also mark the cases with a marker to load into the die & chamber at the same position, which maybe overkill, just to keep everything consistent, I'm now trying partial neck sizing 1/8 down from the neck, my thinking is the case should be as close to the chamber for maximum accuracy, as long as the case can eject. Using RCBS neck die, nothing fancy. Just take your time,use the same make brass, some brass is thicker than others. uniform primer pockets, deburr flash hole, check case size, chamfer inside & out. Also try different primers & seat to bottom of pocket. It's fun to reload, trying to get the round as accurate as possible. Hope I helped in some way. Be safe Chris
 
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m&p45acp10+1

New member
I would suggest if using the collet die to also use the dead length seating die as well. It has made more of a difference in my groups than the sizing die did. Though I give a slight edge in group size to the collet die my a slight margin.

I tested seating dies using an RCBS seating die. With, and without crimp, and using the Lee dead length seating die. The seater made a 1/4 inch difference using five shot groups at 100 yards.
 
C

chiefr

New member
Everyone has their own opinions for ultimate accuracy as far as case prep.

I like uniform case lengths and strictly NSO. I prefer the Lee collet die for NSO. You get the added benefit of extended case life.
 
6

603Country

New member
Ok Bart, you tell me what die to buy and I'll buy it. I have to admit that I'm not that fond of Lee equipment, and I haven't ordered anything yet. Maybe a Redding collet die is what I need. As for seating dies, I use Redding comp seating dies for most all calibers. All this shooting might take months, so I'll buy more bullets.

Tell me specifically what die I need and I will buy it and use it. Money isn't much of a problem unless you tell me that it's made in Switzerland by elves and only during a full moon, and made from Unobtainium.

No point in doing this if I don't do it to the point that I satisfy myself. And no matter what I do, somebody can say that "well, ya shoulda tried this...". And I still wonder if I'll get data that firmly suggests that one thing is better than the other things. And...I'm doing this at 100 yards, so that leaves me open for somebody to say "well, ya shoulda done it at 600 yards". There will always be somebody that isn't satisfied or convinced, and there's nothing that I'm going to do that will be forever regarded as the official and final answer, and that's fitting. I'm doing this for my own edification, though I will report what I find if it's worthy of being reported.
 
H

HiBC

New member
You never know all the variables that will cross paths.What you are learning for that rifle may not apply to another rifle.Still,you are a handloader seeking improvement,that is cool.

Wild guess,the full length resize is giving the clearance for your round to find its own center as it expands.Perhaps thetre is a touch of roundness or concentricity error in the chamber.A randomly indexed neck sized round may be placed in a bind,forcing the bullet to not enter the leade square and straight.

On partial sizing,1)check the case body taper on a cartridge drawing.Determine case taper per inch,included angle.

Now,how much do you back off the die? .050?Suppose total case taper is .010 per in,and you back off 1/20 of an in,the diametral change in the amount you size the brass would be .0005.Now,if you only back off .010 to not bump the shoulder,the diametral change is only .0001..Make a mark on a piece of flat ground steel with a sharpie and run a .0001 dial indicator over itto see how small .0001 is.

Point:partial sizing has very little diametral effect on the brass sizing operation unless you have extreme case taper.

Partial sizing 2)Take a peeled bananna,put it in your fist.Squeeze.What happens to the bananna?So,sizing down the dia of a case without bumping the shoulder,what happens?The shoulder moves forward.IMO,it is best the shoulder gets some (just enough) bump to establish uniform,correct head clearance .That is my ideal for full length re-sizing
I can see no theoretical advantage to partial sizing,where the shoulder is uncontrolled.The diameter of the brass is sized the same for practical purposes,only the shoulder bump is omitted.

Some neck dies are "neck and bump " dies,which do restore the shoulder dim,but do not alter case body dia.
 
B

Bart B.

New member
603country, I like your attitude. So get a Redding full length sizing die with a couple of bushings.

Redding's full length bushing dies are popular with virtually all centerfire rifle competitors as well as Sierra Bullets. Sometimes they'll get one made that matches their cases' dimensions more precicely but they still size down fired case bodies and set shoulders back about 1/1000th inch. They use bushings with diameters 1 to 2 thousandths smaller than a loaded round's neck diameter. I don't think that's needed unless you're shooting hand made bullets in 22 or 24 caliber barrels in short range benchrest. Even then I think it would be hard to see any difference.

Most any seating die will do a good job if the sized cases have straight necks that are not too much undersize for bullet diameters. And full length sizing dies without expander balls but instead bushings (or their neck sized to a bit smaller than loaded round case necks, just like bushings) have always made case necks straighter and better centered on bottleneck case shoulders because the case body is well supported when the neck' sized down and the shoulder's set back a bit. Neck only sizing dies cannont do this and never will.

I've said this before and here it is again. Sometimes, neck only sizing will shoot just as tiny groups as full length size cases. Benchresters learned this years ago. But most interesing is what happened to the largest test or competition groups they fired; they got smaller. Less "fliers" or "wild" shots. Aggregate scores are based on average group size across several from small to large. If the largest groups are smaller, the aggregate winning numbers are smaller. They miss their aiming point not as much as they did with all sorts of neck only sizing.
 
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