FULL LENGTH vs NECK SIZING load development

[DsrtRat]

When developing a load, does it matter if you use F/L vs NECK sized brass? More specifically, I just got some brass and some new bullets that I want to try. If I do load development on the FL sized brass and use that same brass later and neck size it, will my load development be shot out the window? How much difference does it make?

I know the fireformed brass will be a larger capacity, but when FL stuff is fired, it grows to the size of the chamber anyhow. Does fireforming tae much of the energy of the powder to do?

 

[John Y Cannuck]

I've never heard anyone complain of it, and never experienced a noticeable difference myself.
Fire forming doesn't take a lot of pressure.

 

[rral22]

I have seen no evidence that it matters.

 

[DsrtRat]

That is what I was thinking but being new to all this, I often come to CGN for advice.

Thanks guys.

 

[Shaznay]

I would not worry to much about going to neck sized brass. Your only worry really there, is that it won't fit in any other chamber.

I keep 100 rounds for each of my 8x57 JS Mauser K98's and they are all neck sized in their own plastic MEC ammo container. Just gives me peice of mind, knowing that the ammo is custom made for each rifle I shoot.

I can load neck sized cases way faster then FL. It's not as messy having to use case lube all the time with FL sizing

I think you might run into more problems with dropping exactly the right amount of powder, or changing components and seeing the velocity fluctuate

 

[rookie wildcat]

If you are just starting reloading then there is no discernible difference between the two WRT load development. However, if you want to be completely anal, put a few grains (not more than 1/4 max load) of powder in and fill the mouth of the case with a small wax plug. Fire this and you will have gently fire-formed your brass. Then neck size it and begin your load workup. Make sure that you have a minimum of 100 cases before you start. Load development takes LOTS of rounds and LOTS OF TIME. I usually take a minimum of 50 just to work up a round and a half day at the range. I start at 5% below start load and take it to the max load in stages of .5grn. I load 5 of each charge. I shoot 3-rd groups (the other two are in case of bad fliers) letting the barrel cool between shots.
When I find the one I want, say 45grn is a little open and 45.5 is tight, but 46 opens up again. I will load some at 45.3grn and 45.8 gr. I take a loading set-up to the range with me (all I use is a lee hand press with dies, RCBS digital 750 scale, and a powder trickler at the range in my truck) the cases are already done, the die is already set, just seat the bullet and then crimp the round. Fire for effect. I will then go home, make 100 of that round, go back to zero my rifle. I chrony a minimum of a 10 shot string and shoot a minimum of 50rds to become familiar with the round/rifle combo and still have 50rds left for hunting. RECORD YOUR LOAD SPECIFICS!!

Once I have the load chronied, then I can zero for MPBR. The rest is hard work, hauling the game from the woods.

 

[warrenb]

I start with non fire formed brass to find a load. Then when all the brass in the batch is fire formed I go back and test loads again around the best node that I found. I personally think neck sized, fire formed brass is more accurate. So even if the charge does'nt change the accuracy results are better.

 

[CyaN1de]

I start with non fire formed brass to find a load. Then when all the brass in the batch is fire formed I go back and test loads again around the best node that I found. I personally think neck sized, fire formed brass is more accurate. So even if the charge does'nt change the accuracy results are better.

This is due to the fact that the brass is now all uniform in size in relation to the chamber and less stretch occurs for the brass to reach and grip the chamber wall on firing.

 

[DsrtRat]

Thanks guys. I have been reloading for a couple of months now. The fireformed/neck sized stuff seems a touch better than the F/L but my gun is not that fussy.

I was more concerned that if I did a bit of load development with full length sized brass, shot it once and the neck sized it, my data would be way off, possibly bringing me out of a node and into a scatter group.

I recently did a small 3 shot test on some 65gr bullets out of my 12 twist .223. As you can see, I went up at .3gr increments and there are some definate differences in accuracy. I was meticulous about shooting the rounds in a sequence like 123cool the barrel 456 cool the barrel then start 234cool 561 cool etc.. Unfortuntely there was a quartering rear crosswind that day but again, I was more interested in seeing if I could make these bullets fly. Not sure if that is the reson I have an angled stringing to my groups or not but there is definately a top left to down right pattern to the groups. The scatter group stands out like a sore thumb though!

In this case, I was more interested in knowing that I could stabilize 65gr bullets but the results defintely have given me some data to build on.

I use a Lee Collet die.
The gun is a used 1989 factory barrel and trigger REM700 BDL with a custom boyds/bedded stock. Hoping to work this 65 gr load into a .3 or less MOA load.

 

[pockets]

In loading for my 223, I found from full length sized to neck sized the load it liked best increased by .6 grains. Case stretch, and chrony readings verified that pressure dropped with the neck sized brass.

 

[DsrtRat]

Hmmmm, good to know. I suspected there might be some change between the two.

 

[Mystic Precision]

Depends on the chamber sizing and how different that is from your FL die.

some match shooters set up their chambers for a specific FL die - essentially, it does the work of a neck die and body die. ensure positive chambering AND a nice fit so the neck stays true with the bore.

The Redding Type S FL sizing die is get such a die. Another variant is the new Forster Body/Bump sizing die - very neat design.

Otherwise, we don't use FL sizers

1) the neck sizing of the FL die may be excessive and this can lead to bullet seating runout
2) the FL die may be so much smaller then the chamber that brass break in short order
3) the smaller sized case may now sit 'low' in the chamber causing all manner of bullet engraving issues
4) the expander ball/rod may not be true to the neck causing runout as it is drawn through the neck

Because factory rifles tend to have a larger spec chamber and die makers lean towards the small side, the excessive tolerances spawn neck sizing.

I neck size to control the neck tension and keep the necks true with the case body ie no runout. Lee collet and match bushing dies do this very well. No expander rod.

I use a Body die to bump the shoulder and maybe touch the base a schnick to ensure proper chambering and near zero headspace - case stretch is within the tolerance of the alloy and cases last a very very long time.

so the debate of FL vs Neck has more to do with chamber vs die.

As long as a case chambers properly with the bullet true with the bore AND with no runout, doesn't really matter how you got there.

And yes, I use dirt cheap standard dies from various makers to deal with varying chambers. ALL manfs vary in size and by having a nice selection of dies, you can usually get brass to work optimally in any within spec chamber.

I also use some more expensive seaters and body dies if they are the best solution to a wildcat or factory chambering.

I always do my load development with fireformed brass. For the type of accuracy I am after, the change brass undergoes in that first firing WILL affect my load development. Plus it enlarges the case to ensure a better fit.

Jerry