.303 Brit- Help me understand, Lee collet die.

[1shot]

Happy new year!

I am about to begin loading my own boolits for the 5 groove .303 Brit, she slugs at .314 and the expander ball on my die measures .310 which is far to small to be useful.

Wondering if the Lee Neck/Collet die would be the answer.. As I understand, the Lee collet die squeezes the neck from the outside to an inside tolerance preset by a mandrel.
So, as I will be loading CAST boolits of .315 diameter- can I preset the die to squeeze the neck down by just a couple of thou less than fired diameter without touching the mandrel- for correct boolit fit?
Comment and suggestions please.
Cheers!

1Shot

[1hole]

"..can I preset the die to squeeze the neck down by just a couple of thou less than fired diameter without touching the mandrel- for correct boolit fit?"

Semi-sorta. You can easily adjust the die so the collet jaws stop short of the mandrel. At best that will leave the actual neck ID dependant on the actual thickness of each neck. Even so, the variation would be small so it could work fine.

It would be better to get a mandrel the diameter you want. Lee makes customs. Or, if you know someone with a metal lathe, they are quite easy to make. I've done several in my own shop. (I don't bother with a decap pin, do that job with a Universal Decap Die anyway.)

[Jim]

Contact "Buckshot". He can answer your questions AND make a custom mandrel for you.

[1shot]

Thanks guys, I'll go ahead and order one then.

[docone31]

From my experience with my #1MKIII, I had to send the whole set of dies to Lee.
This was before I knew of Buckshot.
I also sent a slugged casting to them.
For nominal cost, they modified the dies. Now it fires well.
I collet reload.

[Bloodman14]

Something I have recently discovered; I finally got the Lee sizer in .314, so that I could install the GC's on my 314299 Mod GB mold from NOE. In measuring the ID of the case necks, I found that the necks were already at .315; the boolits drop at .3155. So, I polished out the sizer to .315, and now the boolits are a press fit into the cases! I will no longer need to neck size my brass, thus increasing its' life considerably. I simply use my neck sizer die to decap, and will until I get a decapping die. IME, YMMV, FWIW.

[Calamity Jake]

Lyman "M" die with .313 expander.

[Three44s]

M dies from Lyman are the ticket for boolits in just about any senario ........

........ and I have gotten a different mandrel for a Lee collet before as well.

All good choices and both will likely work together better than one or the other.

Three 44s

[BerdanIII]

If you have one, you can use a .308 WCF trim die as a neck-sizer for 0.314" and larger boolits and flare the case mouth with an RCBS tapered expander or Lyman M die. You can also trim .303 cases with it (I am CHEEP!).

[JudgeBAC]

Like Calamity Jake, my solution was the Lyman M die. My Lyman 314299 cast great boolits. I size them to .314 and use the M die with great results. Currently I am shooting 20 grs. of 5744.

My results with the Lee Collet die were not good with this boolit.

[mdi]

Something I have recently discovered; I finally got the Lee sizer in .314, so that I could install the GC's on my 314299 Mod GB mold from NOE. In measuring the ID of the case necks, I found that the necks were already at .315; the boolits drop at .3155. So, I polished out the sizer to .315, and now the boolits are a press fit into the cases! I will no longer need to neck size my brass, thus increasing its' life considerably. I simply use my neck sizer die to decap, and will until I get a decapping die. IME, YMMV, FWIW.

I suspect this leaves you with little or no neck tension (?). How is accuracy? Consistant ignition? Not critisizing, just wanna know...

[Bloodman14]

mdj, don't know, yet; been busy and the weather is not too friendly right now. I have loaded up several recipes with these cases, and will test ASAP.

[hk33ka1]

I wonder how the Classic Lee Loader die compares to the collet die for these calibres. I have one for .45-70 and .308 but only really use the .45-70. I'd like to just buy the die for .303 Brit and .30-30 to neck size them instead of another Lee collet die. I have a collet die for .308 but have yet to use it much.

[9.3X62AL]

Something I have recently discovered; I finally got the Lee sizer in .314, so that I could install the GC's on my 314299 Mod GB mold from NOE. In measuring the ID of the case necks, I found that the necks were already at .315; the boolits drop at .3155. So, I polished out the sizer to .315, and now the boolits are a press fit into the cases! I will no longer need to neck size my brass, thus increasing its' life considerably. I simply use my neck sizer die to decap, and will until I get a decapping die. IME, YMMV, FWIW.

This is a very close approximation to the sitch I deal with concerning my No. 1 Mk III. .3155" throat, and about .0015"-.002" neck clearance on a boolit sized @ .316", with R-P cases. There is slight neck tension imparted by the 303 British SEATER DIE--just enough to support the boolit through magazine feeding. I seat the boolits by use of an adjusted 8 x 57 seater die, enabling both case neck and boolit clearance. The loads (18.0 grains of 2400/190 grain Wide Thirty) shoot quite well.

[leadman]

Gunnerd, asking a question here. Is .315" the size of a fired case? If so are your bullets going to release from the case without increasing pressures?

[Smoke-um if you got-um]

If you choose to use the fired case as is with the bullet a slip fit you will probably find this a satisfactory way to do it. If the seated bullet and case will chamber w/o resistance pressure will not be an issue. If it takes any effort at all to chamber you will have size a bit in some manner. The brass has about 1 maybe 2 thousands of spring back after firing giving you your .315 inside neck diameter. If you find any smaller than that the neck has thickened or that lot of brass has thicker necks to begin with. W/O any sizing of the brass your lot will probably stay where it is at for a long time. An inexpensive Lee Factory sizing die works very well for the bullet push back issue. I have several rifles that I shoot exactly this way with good results.