.303 neck sizing - how much is enough

[Nora]

I've got a 1953 #4 Mk2 that I've only fired surplus threw so far. I was at the range the other day shooting next top a gentleman and his sons who were working there way threw 200 rds of FC ammo. They don't reload and I was given the brass. I tried feeding the empties to mine and the bolt closes just fine so neck sizing will be the only thing I'll need to do with them. Sense I live in the world of instant gratification and don't have dies yet I thought I would try using my 54R dies for the job. I am only able to get the neck .275" in before the shoulder touches, leaving .075" unsized.
There is plenty of neck to grip the boolit, but is this little amount of unsized going to have any effect on accuracy?
The 54R seating die seems to be working out for this project.

Thanks in advance

Nora

[frkelly74]

I think it will probably work. If you seat the boolits so that they touch the leade of the bore, so that there is slight resistance to chambering a round, then you will effectively fire form the brass to fit your chamber. Then do not touch the shoulder of the case with the die when reloading it. Eventually the brass may get so it wont chamber and then you will have to get proper dies and size them down till they will just chamber. You will not want to actually full length size, only size down to the point that they will chamber. You will be using the shoulder of the case for headspacing the cartridge at that point, not the rim of the case. This is what you want for long brass life and to help prevent head separation.

People will say they hate you for your good fortune, They are only envious.

[303Guy]

There are ways and means of loading boolits into unsized necks. I use paper hand towel strips cut just wide enough so that a 'cross' will filly 'line' the neck circumference. A boolit should seat into that just snugly. Use another case mouth pushed over the seated boolit to cut off the excess paper.

This kind of thing.
http://i388.photobucket.com/albums/oo327/303Guy/MVC-168F_edited.jpg

[DanM]

Yep, I agree that it will probably work fine. I have exactly the same rifle, and only size with the Lee collet neck die. Good accuracy and case life. These rifles love cast boolits....

[3006guns]

Considering that many shooters have just hand seated boolits for years there's no reason why it shouldn't be just fine.

303Guy.......that's a neat trick and I'm going to try it!

[Multigunner]

I only neck size 2/3 of the neck anyway.
Once a case has been fired once I rotate it 180 degrees on second firing, This insures the case body and neck are equally expanded to lay centered in the chamber for subsequent firings.
By leaving 1/3 of the neck unsized the rear portion of the neck acts to present the bullet well centered to the origin of rifling.

I learned long ago that the less neck tension, within reason, the less the adverse effects of variation in neck tension and pull strength.

PS
After each firing I use the fired cases as snappers to practice dry firing to develop trigger control and sight picture.
The firing pin strike alone serves to micro size the cases. When reloaded the cases feed without binding.

[JeffinNZ]

That's heaps. My No4 MkII gets fussy with neck tension so keep an eye on the brass and anneal often.

[303Guy]

My No4 MkII gets fussy with neck tension ...Jeff, may I ask how that sensitivity shows up? Vertical stringing or just opening up of groups?


Considering that many shooters have just hand seated boolits for years ...3006guns, does that mean the boolit bases are large enough to actually get swaged down by the throat taper? (Relevent to me 'cause I am planning on going to plain cast for one of my 303's - I will be trying the paper hand towel seating trick to see how well it does or doesn't work in the 303 Brit).

By the way, a neat trick if you can get hold of a spare or old magazine is to remove the innards and use the mag shell as a spent case receptacle - without the magazine, Lee Enfields drop spent cases down through the magazine well.

[JeffinNZ]

Groups open up. I anneal the living daylights out of my brass and keep the necks soft.

[Nora]

Thanks for the input guys. The 54R dies did work well enough to call that project a success. I was at a gun show yesterday and was able to score a used set of like new RCBS .303 dies from the '70s for $18. It was fun just the same to improvise with what I had to make it work. Now I also have other ideas of things to try in a pinch for the future.

I'm trying to visualize the O ring idea, and would like to give it a try. But how much bigger are they in relation to the external dimension of the cartridge body? Could some one please post a picture as to what that would look like? I'm one of those knot heads that could read a mountain of text books and learn nothing, but watch someone do it once and learn the hole process in 5 minutes. :roll:

Nora

[303Guy]

I'm trying to visualize the O ring idea, and would like to give it a try.Yeah. I'm trying to figure out the right size O ring too.

[mroliver77]

Now adjust the .303 dies to leave that .075 unsized portion of neck.If it gets to where the bolt closes hard, adjust the die to just "bump" the shoulder enough to allow easy chambering. A lot of dies size the neck wayyyy down and then pull the expander back through to open it back up. Size a case with and without the expander to see the difference. Then compare the neck o.d. with a loaded round and it will make you sick! You can open up your die though it takes some doing. Your cases will last a long time if this is set up properly.
Jay

[303Guy]

I've never had to set the shoulders on a 303 case back (the proviso being that it was fired in that rifle in the first place or one with a tighter chamber). I have found that if a case is hard to close the bolt on it will free up on firing. Untill now! It's my Pig Gun. Not sure what's causing it but could be simply too little chamber pressure. It could also be the case filler pressing the shoulder forward as it compacts and forms an oversize wad. Don't know. It doesn't always happen.:-?

I made my own neck sizer die and an expander plug to suite the particular boolit. The amount of sizing I give them is miniscule (when I do find it necessary to size). As Jeff has pointed out, anneal the heck out of the necks for accuracy. It makes for easier sizing to 'spec' and causes less damage to the cast boolit (neck sizing the cast boolit amounts to damage). If you Google JeffinNZ's previous posts on his 303 Brits with cast boolits you will see he has produced very satisfactory accuracy. You might even consider getting a mould like he uses.

[n.h.schmidt]

This is for Nora and 303 guy
The O ring size is not critical. What I have used is 7/16" od and 1/16" thick. My local hardware store has a big selection. I can get the maker and part no if needed. In use, you simply slide the O ring down on the case all the way to the rim. The case is loaded directly in the chamber. The bolt is closed and the extractor snaps over the rim and o ring. The bolt will close a bit on the hard side as the O ring resists being squished. Fire the round and extract as normal. You only have to do this the first time with any case. As far as I can tell the O ring dosn't do anything to center the case. It will hold the case hard against the bolt face and allow the sholder to blow out into the chamber. The O ring may not last very long as the extractor is hard and sharp edged and will eventually cut into the O ring.
303 guy I realize you may not have good access to O rings,or at least the same ones I can get here. If needed I can send you a few.
n.h.schmidt

[303Guy]

Thank you for your kind offer, n.h.schmidt. Now that I know the size that works I'm sure I'll be able to find some.:-D

[Nora]

Thanks n.h.schmidt that's a description I can work with. A trip to the hardware store is now on the list of things to do in the a.m. It will be fun too to compare targets from before during and after the O rings and see what kind of difference it will make besides lengthening the life of the brass. :grin: