My new 303 brit neck sizer.

[Johnch]

I was going to buy a Lee collet sizer for my 303 , but I have not made it to the gun shop to order one.

I was cleaning the reloading bench and picked up the carbide 32 H&R mag dies .
I had a brain storm or brain fart depending on how you look at it.
The 32 H&R mag is .337 the 303 neck is .338 .
Sizing is by touch , you can't run the ram all the way up .

I sized 50 of my Sellier & Bellot cases ( the best 303 cases I have ever used) touched the case mouth with the M die and loaded some water droped Lee C312-185 over a charge of AA 5744.

I do not touch the shoulder due to the oversized chamber .
When needed I bump the shoulder back with a bored out F/L die , a touch but leave the body alone .

I was at the range Sunday AM and got to try the loads out .
Best group was .85" ( some luck )
The rest were about 1.5" -2" , this is caused by my eyes not the gun.

I am not saying to run out and buy a 32 carbide sizer , I had it , it worked great .
AND I an a cheap SOB that hates to spend a nickel if I can make it

Johnch

[Mel-4857]

Neck sizing is the way to go with the 303 British. I bought a lee die two years ago and use it all the time. Seperate my brass because I have several 303's.I really like your idea of oversizing the sizing die so it just sets back the shoulder. I've had good luck with Herter's Brass it was supposedly made in Sweden. I know Herters has been in business for a While but my surplus Powder supplier up here must have bought a bunch of it. It comes in 20 round boxes. Thanks for the ideas. Mel

[NVcurmudgeon]

Another good neck sizer for the .303 is a 7.65 X 53 Argentine Mauser full-length sizer. Adjust the 7.65 die to touch the shellholder, then raise .030".
So adjusted, the whole .303 neck will be sized, without touching the shoulder or body of the case. (Head to top of shoulder dimension: .303 British 1.090",
7.65 Mauser 1.060".) The things we learn when we shove the wrong brass into the right die! Neck sizing is probably of more case life benefit to the .303 British than any other cartridge. For more on this subject see www.303 British.com.