303 brit and neck tension issues,

[mac1911]

Ok so I have been loadingcast for my 1903a3,mosin 762x54r with good results and very little issues, heck I dont even have any leading issues...

Now moving on to 303 brit.... I been loading FMJ with out issue with the lee deluxe set using the neck size die... Moving on to cast..
Bullet is the 314299 as dropped is just a touch over .314 my rifle slugged at .3128ish few slugs came in at 313.... so I figure the .314 would do well as dropped.
I neck sized as before for FMJ... I found that the cast boolit can easily be moved in and out of the case.... I tried adjusting the die a tad more but The OD of the neck doesnt get any smaller than .335 (currently dont have a way to measure ID)
The boolit feels snug when seating but When I check the boolit can be easily spun and moved in and out with just fingers.
I plan on at least using the 303 for 100 yds with 2400 or maybe with
H4895 but cant see getting a good ignition with bullet this loose? I also see the boolits setting back if I mag load?

What am I missing, ohh and I ordered a 303 FCD and recieved a 762x54... thats ok as I have the 54r dies to add it to?
I flare with a universal flare die, I think its lyman..

[atr]

use a minimum flare..just enough to start the gas check. Then roll crimp just enough to take out the flare.
you might also try measuring the expander on your sizing die to make sure its not too large. Also measure the diameter of your boolit....
also your flareing tool might be enlarging the case neck ....try seating the boolit without flareing
atr
ps...since the neck expander on the sizing die seems to be ok for J's I would suspect that your flareing tool is the problem or that your are over-flareing.

[nhrifle]

Pull the expander button from your sizing die and measure it. Might be expanding the necks a bit much. Also may need to anneal your case necks.

[Maven]

Any chance the .303Br. brass needs annealing, mac1911?

[303Guy]

Well, I aim for a boolit fit like you are getting. My idea is to hold the boolit with the lube and to that aim I've developed a prototype lube that gets melted and the loaded boolit and neck dipped into it so it melts the lube on the boolit and when cooled, holds the boolit fairly firmly in the neck.This has worked quite well with a rather heavy boolit over a mild load of Varget (AR2208). I'm not sure how robust this would be But I do intend pursuing the idea for magazine feeding. That's in a 303. The idea works in a hornet.

Neck annealing may be the answer. For cast, it may be an idea to fully anneal the necks. The faster powder you are using may not require too much neck tension.

[Janoosh]

Question:
What size is the expander for 7.62×54.?
What is the final neck size from the 7.62×54 sizer die.?
It may be possible to just neck size the 303 using the 7.62×54 sizer die.
I believe the body taper and size differs enough to work in your favor.
Then, it's all about the expander.

[mac1911]

Question:
What size is the expander for 7.62×54.?
What is the final neck size from the 7.62×54 sizer die.?
It may be possible to just neck size the 303 using the 7.62×54 sizer die.
I believe the body taper and size differs enough to work in your favor.
Then, it's all about the expander.

IU have not checked the 54r sizer die, I thought about using the 54r sizer but would like a solution to my problem.

I bought a new Cal with inside measurement ears. Neck ID must be smaller than .312 as Thats what I use for FMJ. They dont budge. I can press bullet tips hard against the bench and push and they dont budge.

The cast boolits measure .314+
Brass is once fired HXP and PPU both have the problem, cant seeing needing to be annealed Being 1x fired?

Could I be sizing down to much and the cast boolit blowing out the neck...?

[303Guy]

My suggestion to fully anneal case necks was to do with controlling neck tension. By fully annealing them the neck tension is reduced. It's also easier to achieve a specific internal diameter as the brass will have less spring back. I have fully annealed case necks for jacketed bullets and they worked great. More consistent neck tension I think.

[longbow]

Oddly I had exactly the opposite problem.

My RCBS dies were sizing to 0.311" or so inside the neck while the throat runs slightly over 0.315" and groove diameter is 0.314" so I use fat boolits of 0.315".

Accuracy was lackluster to say the least and I was getting some leading so I decided to pull some boolits and found that the RCBS dies were sizing necks to the point that the boolits were being resized smaller at seating. My first move was to make a new expander button to leave case necks at 0.313" after sizing and that helped bunches. Neck annealing also helped.

However, I realized that the brass was still being worked pretty hard by all that sizing so wound up buying a Lee collet die and made a new mandrel to give me 0.313" inside neck diameter after sizing. Good accuracy and no longer working the brass so much.

I find it odd that your set up is resulting in loose boolits, especially when jacketed are okay.

Possibly 303 guy has nailed it with spring back if necks are not annealed but then that should also apply to jacketed bullets. Other wise something else is at play here.

Longbow

[mac1911]

Oddly I had exactly the opposite problem.

My RCBS dies were sizing to 0.311" or so inside the neck while the throat runs slightly over 0.315" and groove diameter is 0.314" so I use fat boolits of 0.315".

Accuracy was lackluster to say the least and I was getting some leading so I decided to pull some boolits and found that the RCBS dies were sizing necks to the point that the boolits were being resized smaller at seating. My first move was to make a new expander button to leave case necks at 0.313" after sizing and that helped bunches. Neck annealing also helped.

However, I realized that the brass was still being worked pretty hard by all that sizing so wound up buying a Lee collet die and made a new mandrel to give me 0.313" inside neck diameter after sizing. Good accuracy and no longer working the brass so much.

I find it odd that your set up is resulting in loose boolits, especially when jacketed are okay.

Possibly 303 guy has nailed it with spring back if necks are not annealed but then that should also apply to jacketed bullets. Other wise something else is at play here.

Longbow

I have not played to much with it.
My Mandrel/expander both measure .309" in the 54r and the 303 brit dies ? My flare tool does not expand the neck it just puts a small flare on the brass, its just big enough to where the lip of the gas check settle inside enough to have the bullet balance on top.? It must be the brass ? I use the same .314" cast boolit in my 54r?
Any how went to play with it and was not thinking and my press over cams , sssooooo I blew out the aluminum threads on the 303 collet sizer. Good time to order a new one and a larger mandrell I quess.

[MT Chambers]

I wouldn't have wasted money on the FCD, instead I would get a Redding Bushing neck die, this way you can dictate exactly how much case neck tension you want. I have them for all my calibers in which I want top accuracy and REPEATABILITY.

[W.R.Buchanan]

I sized the necks only with an RCBS FL die backed out and then expanded just enough to get the gas check in the hole. I roll crimp separately with the other RCBS die but seat with a Lee Die. I got a FCD also but that is for Jacketed bullets to crimp in the cannelure, that's where FCD's actually work right.

Randy

[Mr Peabody]

I bought a Redding neck sizing die for the 303. Everything is sized right and I use the M die for .30 caliber to flare with.

[Mike H]

The Lee .308 Winchester Full Length die makes an excellent neck size die for the .303 British cartridge.
Mike.

[longbow]

Wouldn't a .308 die squeeze the neck down too much? I had trouble with my RCBS .303 dies sizing my necks down to 0.310"/0.311" then my 0.315" boolits opening the neck back up. Hard on brass and hard on boolits. That's why I went to the Lee collet die with 0.313" mandrel.

[Motor]

mac1911,
Don't feel bad my Lee 7.5x54 die set came with a 7.62x54R size die. I called who I ordered it form and they called Lee. Lee sent me the correct die and said just keep the 54R die. Like you I was happy with that because I had opened up my own Lee 54R size die so it would size the neck down less for use with .312" bullets.

The standard 7.62x54R die sizes the neck to hold a .308" bullet. Most people buy the optional .303 expander as did I. I just took this one step farther and modified my size die to match. I couldn't see sizing it down just to pull a larger expander back through it.

You can eaisly measure the inside diameter of your case necks. Just measure the OD, then measure the wall thickness. Subtract the wall thickness x2 from the OD.

Motor

[mac1911]

Well I have not ventured back into the problem but I think what is happening is when I seat the 314" bullets its blowing out the neck rather than pressing into it.
When the holidays pass I will get back to the issue. I think a larger expander will help... I did get to test my 3 loads today and was pleased with the out come so far. once the paper targets are dry I will post pics.

[leadman]

You have to size the boolit enough so the gas check is sized to the same size as the boolit. If the GC is larger than the boolit it will result in the case neck being too large for the boolit.
The sizing die is tapered at the top and reaches stated sizing diameter around 3/8" into it. This is for the H&I dies for the Lyman and RCBS machines.

[mac1911]

You have to size the boolit enough so the gas check is sized to the same size as the boolit. If the GC is larger than the boolit it will result in the case neck being too large for the boolit.
The sizing die is tapered at the top and reaches stated sizing diameter around 3/8" into it. This is for the H&I dies for the Lyman and RCBS machines.

Im sizing a 30 cal gas check onto the 314" bullet useing the 314" Lee sizer. I do not have this problem with the 7.62x54r reloads with the same bullet.

Things went pretty well to day rear sight was set @ 400 yds and I was aiming center of bull.
1. 10 grain Trail Boss was the least impressive. Raining today and that target got to wet and fell apart. 50 yards I got some vertical stringing aprox 4" windage was pretty good.
2. 16 grains 2400 not to bad but was hoping the "load" would be better....more work here

3. 30 grains H4895 by far the best I have pulled out of the 303


My goal is a light recoil, inexpensive 200 yard load. Just looking to hold the black of a SR target

I love shooting cast and having input from the range guru's
Quotes for today
"You better check that surplus ammo it sounds off " "hey man I think you hitting the target frame I hear the bullet smacking it"
" You know that rifle is made for 100 yards right, your sights will be way off @ 50 yards"

[leadman]

Since you are using a .314" sizer this seems to point to the brass. Has it been annealed too soft? Is the sizer actually sizing the GC down to .314"? I have bought a couple of Lee sizers that were oversized.

I have found in my rifles that the 16grs of 2400 does not produce the best accuracy. Usually works out good at 18 or 19grs.