• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

Full length resizing vs neck sizing.

Vin

Sergeant
Full Member
Minuteman
Jan 4, 2004
134
0
59
I am just starting to get into reloading, hopefully for competition shooting (F/TR) down the road.It seems like you ask 5 guys and get 8 opinions. Is there an advantage to just neck sizing with respect to accuracy or does it matter if you just full resize.I know that consistency , bullet seating depth, powder weights, etc play a part in the accuracy thing but will how you size whether full length resize or just neck size play a part. I am not concerned about brass life so that is not an issue. Reading about bushings and correct size, neck tension and all that stuff makes my head spin. I know there are different types of neck sizing dies out there. I have a Redding competition seating die but at this point don't know what to do with respect to sizing, neck or full length resize. Any opinions for a person just starting out. I tried to search but got no results for what I was looking for. Thanks.
 
Re: Full length resizing vs neck sizing.

"It seems like you ask 5 guys and get 8 opinions. "

True. And anytime that happens you can be sure of two things; each is correct ... for himself... AND none of them may be true for you!

Neck sizing may or may not help an individual rifle, it may or may not help case life; only way to KNOW is to try it yourself. Ditto a lot of other hotly contested ideas and personal preferences.

My opinon for bushing neck dies to use with SAAMI CHAMBERS is to get a Lee Collet Neck sizer instead and be done with it without trying to get an exact inside neck hole in inconsistant necks by working on the exterior. For a case that's already a sloppy fit that's a pointless exercise and the inexpensive Lee neck die does very good work with normal case necks.
 
Re: Full length resizing vs neck sizing.

I'll give you a brief teaser of what I have seen.

Me and a friend of mine are doing a "controlled" test to determine brass life between FL sizing and Neck sizing and annealing vs. not annealing.

First of all, I put controlled in quotes because this is not in a lab, but we both come from scientific backgrounds and we have done our absolute best to control all the variables in this test. We have kept a notebook and carefully recorded all details related to the test. We are running sample sizes of 5 pieces of brass per test group. The brass is all R-P 308 brass once fired from the test rifle, all brass came from the same lot of factory ammo. Annealed samples are annealed every 5 reloads.

Neck sizing no annealing we saw case life between 80-152 reloads.
FL sizing no annealing case life was around 17 reloads IIRC.
FL sizing with annealing was around 12 reloads.
Neck sized annealed test group is still in process... it's tedious to do the testing.

Moral of the story? Annealing decreases case life when FL sizing (I can further explain our theory if you want). Neck sizing gives you MUCH, MUCH more brass life.

Neck sizing also gives you much less brass prep. Over the course of 152 reloads on the neck size test group there was negligible case growth.

While on 12 reloads of FL sized annealed brass we saw up to .070" of growth.

When we complete our test I'll post up the full details. We've discussed publishing a "scientific" paper on our finding when we complete the test. We're both into this test pretty deep on cost. Over 1k rounds fired, expecting that number to exceed 2k rounds.
 
Re: Full length resizing vs neck sizing.

Hmmm. This should get interesting...
 
Re: Full length resizing vs neck sizing.

"80-152 reloads"????
 
Re: Full length resizing vs neck sizing.

It really isn't about FL vs. neck sizing, as such. The question of case life from neck sizing vs. FL is dependant on two parameters; the actual dimensions of the chamber AND the die being used. If the chamber is smallish and the die is largish we will get very good case life; other way around case life will be short. And that applies to both FL and neck sizing.

Annealing only applies to necks (at least it had better be) and properly annealed necks will last viturally forever when sized in a Lee collet neck die.

If your FL cases stretched 70 thou with 12 cycles you are setting the shoulders much too far back and are inviting a head seperation.
 
Re: Full length resizing vs neck sizing.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: thefitter</div><div class="ubbcode-body">"80-152 reloads"???? </div></div>
Yes, there was one outlier in the group that fell out early. IIRC (I don't have the data book with me) is that the remaining 4 cases lasted between 115 and 152 reloads.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">It really isn't about FL vs. neck sizing, as such. The question of case life from neck sizing vs. FL is dependant on two parameters; the actual dimensions of the chamber AND the die being used. If the chamber is smallish and the die is largish we will get very good case life; other way around case life will be short. And that applies to both FL and neck sizing.

Annealing only applies to necks (at least it had better be) and properly annealed necks will last viturally forever when sized in a Lee collet neck die.

If your FL cases stretched 70 thou with 12 cycles you are setting the shoulders much too far back and are inviting a head seperation. </div></div>
We felt that as a matter of consistency we should set the case back as close to SAAMI specs as possible when FL sizing, so that is what we did. I'm sure many will criticize and nit-pick the way we conducted the tests but that is really besides the point. The purpose of the test is to compare annealed vs. non-annealed. The comparisons between FL sized and neck-sized are really just "interesting". We can't conclude much from the comparison that we didn't already know. The real comparisons come when looking at the annealed vs. non-annealed samples of the same sizing technique.

I don't see anybody else setting aside their funds and time to conduct controlled tests like this.

We shall certainly see if brass will last virtually forever with annealed necks. We're on reload 25 or so of the neck-sized annealed test group and will resume testing sometime in the next few weeks. We're going to try to get this wrapped up before I deploy since the test rifle is mine.
 
Re: Full length resizing vs neck sizing.

Please explain your theory on why annealing decreases case life with FL sizing
 
Re: Full length resizing vs neck sizing.

Another note. How far back were you setting the shoulder from each firing?
 
Re: Full length resizing vs neck sizing.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: palmik</div><div class="ubbcode-body">Please explain your theory on why annealing decreases case life with FL sizing </div></div>
This may be hard to understand without pictures but I'll give it a shot.

Just to clarify, all failures experienced with FL sizing were incipient case head separation. We didn't go to full separation, but up until the point that we were certain that full head separation would occur with the next firing; some cases did have partial separations (see light through case wall).

To begin we must understand the mechanics of incipient case head separation.

When a case expands inside the chamber the walls of the case near the shoulder (where the brass is thinnest) expand out and "lock" onto the walls of the chamber. Then, the case head expands backward to the bolt face. This stretches the the case wall and creates a small area of thinner, weaker brass right at the thin point where the head transitions to the wall. This is what ultimately causes incipient case head separation. I think all would agree with me on that.

Now, when full-length resizing brass, "bumping" the shoulder back translates into some of the brass from the wall flowing to become part of the shoulder, and some of the brass from the shoulder flowing to become part of the neck. The neck (and case length) ultimately grows as more brass flows up the case wall, into the shoulder, then into the neck. All the while, this keeps stretching the thin/weak area near the head thinner and thinner.

The difference is that with non-annealed brass, the shoulder/neck area is rather hard, and the brass doesn't deform as easily. Rather than the brass from the shoulder flowing into the neck area, the die directly pushes the entire shoulder/neck area back down, replacing some material in that thinned/weakened area where the case head separation will ultimately occur. The next time the case is fired, there is more material in that weak spot and ultimately, it takes longer for the brass to weaken and crack in that area.

OTOH, annealing the brass keep the neck/shoulder soft, and allows the brass to flow more readily into the shoulder/neck area. Because this brass flows, and the case grows in length, rather then the displaced material being replaced back in the same place it was displaced from, we see incipient case head separation much sooner with annealed brass.

Our theory is corroborated by our overall case length growth numbers. The annealed brass, over ~12 reloads grew as much as .070", while the non-annealed brass, over ~17 reloads only grew about .030".

Disclaimer, all numbers posted in this thread area based upon memory and may not be 100% accurate. My partner has the records we took, and I'm on TDY right now.

ETA, we didn't measure how much we were setting the shoulders back, but that would be a good measurement to take. I will address this and maybe we can run a small test batch to see how much the shoulder is being set back. The reloading setup has not been changed at all through this entire experiment.
 
Re: Full length resizing vs neck sizing.

Question, were you setting back the shoulders on every reload or some interval?
 
Re: Full length resizing vs neck sizing.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rmercado</div><div class="ubbcode-body">Question, were you setting back the shoulders on every reload or some interval? </div></div>
On FL sizing we were setting the shoulder back the same every single reload.

On neck-sizing, we did occasionally run the brass through a FL die when it got hard to chamber. IIRC, only 3 or 4 times in the whole cycle of neck-sizing did we have to FL size.
 
Re: Full length resizing vs neck sizing.

Your case head separation was due to bumping the shoulder too much, not just because you were full length resizing.
 
Re: Full length resizing vs neck sizing.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bward</div><div class="ubbcode-body">Your case head separation was due to bumping the shoulder too much, not just because you were full length resizing. </div></div>
Once again, the purpose of this test isn't so much to compare FL sizing vs. neck-sizing, it is to compare annealing vs. not-annealing.

Either way, if you bumped the shoulder less you're still going to see less case life with FL sizing, that fact has already been demonstrated in many tests by other people. As a matter of fact, we did have one of the FL sizing samples that was already starting to neck crack. Not entirely sure what that is attributed to but we have a couple ideas.
 
Re: Full length resizing vs neck sizing.

There's a lot of guys out there getting 15-25 loads out of brass that anneal and full length size. Most guys who shoot matches buy at least 300 pieces of brass for a barrel. Even at 15 reloads your brass is going to outlast your barrel.
 
Re: Full length resizing vs neck sizing.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: thefitter</div><div class="ubbcode-body">"80-152 reloads"???? </div></div>

Countryboy,
did you have to bump the shoulders on these 80-152X neck sized cases? If not, thats incredible!!
 
Re: Full length resizing vs neck sizing.

Just to clarify, all failures experienced with FL sizing were incipient case head separation....To begin we must understand the mechanics of incipient case head separation."

A head seperation is a head seperation, 'incipient' only means there are visible signs of a coming seperation.

The cause of head sperations is no secret, most of us are well aware of it. You describe parts of the cause of impending seperations but, by your determination to restore the shoulders to exessively short SAMMI dimensions you're destroying your cases by stretching alone; your neck annealing has no part of the destructive results. In fact, you're skewing your "test" basis so badly it can't provide you with any valid information for what you seek to discover. If you really want to know the difference between case life with FL and neck sizing, work with the necks, not the shoulders.

Lay your SAMMI gage aside and size FL your cases properly, to fit the chamber as snugly as you can chamber 'em. THEN you will get an idea of any differences. But even then all you really gonna see is the results for YOUR chamber and YOUR neck and FL dies, not ours because our's are different from your's.

Keep your head down and stay safe.
 
Re: Full length resizing vs neck sizing.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bward</div><div class="ubbcode-body">There's a lot of guys out there getting 15-25 loads out of brass that anneal and full length size. Most guys who shoot matches buy at least 300 pieces of brass for a barrel. Even at 15 reloads your brass is going to outlast your barrel. </div></div>

I am getting 30-40 reload cycles on 308 Win brass with NO ANNEALING and NO sizing most of the time popping out 155 Scenars at 2950 fps with 47.8gr Varget. Over 32 firing cycles, I have lost 2 cases to body cracks and 2 cases to insipient case head separation (out of 50). I NO size in two steps from an obturated size of 0.3445 with a 0.338 bushing and a 0.332 bushing giving me <about> 0.002 in neck tension.
 
Re: Full length resizing vs neck sizing.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nflder</div><div class="ubbcode-body">I am just starting to get into reloading, hopefully for competition shooting (F/TR) down the road.It seems like you ask 5 guys and get 8 opinions. Is there an advantage to just neck sizing with respect to accuracy or does it matter if you just full resize.I know that consistency , bullet seating depth, powder weights, etc play a part in the accuracy thing but will how you size whether full length resize or just neck size play a part. I am not concerned about brass life so that is not an issue. Reading about bushings and correct size, neck tension and all that stuff makes my head spin. I know there are different types of neck sizing dies out there. I have a Redding competition seating die but at this point don't know what to do with respect to sizing, neck or full length resize. Any opinions for a person just starting out. I tried to search but got
no results for what I was looking for. Thanks. </div></div>

I always fire form the brass then neck size my brass used for my match rifle (ftr match) not sure how much, or if it improves accuracy. I do think the improvement is very minimal, but it can matter in a match. If the brass exactly fits the chamber, then that is more energy sent down the barrel and not used for deforming brass. I think it would provide a more focused and uniform blast. Just my opinion
 
Re: Full length resizing vs neck sizing.

All I can say is that I FL size the first time and then neck it from there on out. I can't say that I can note a difference in accuracy between either way in my rifle. I can say that my brass lasts longer by just necking it after the first initial FL sizing. I don't shoot matches, but I do strive for the utmost accuracy I can obtain from my reloads and they perform much better than any out of the box ammo that I've found, including FGMM and Remington Premier Match ammo. I would say that 118LR is pretty dam hard to tell the difference, but the reloads that I've got going now perform fractionally better from what I can tell. Now this is just my opinion and in my rifle, so results will vary. I also use a Lee neck sizing die, which is actually a set that includes an FL die. I have yet to use a bushing die, so I can't attest to the results one could achieve from that. I've found that it's been best, for me, to simply find a powder charge that works well and then toy with the seating depth and such. Again just my results, so take them as you will. Good luck with you're decision, Jason