45-70 FL size ?

[kokomokid]

Do you full length size your 45-70 and what brand die are you using? What is your average bullet run out or concentricity?

[country gent]

I only neck size my brass I have a meacham bushing die and only size to bullet depth to hold the bullet completely. I also size to hand seat bullets. I get very accurate loads this way. "soft seated" allows for bullet to float into throat and lead more evenly. I have 45-70 and 45-90 going on 9 reloads and still chambering easily. If your shooting more than one rifle in the caliber then full length sizing may become neccesary due to chamber diffrences. With a full length sizer die only runningpartially in to die can acccomplish sizing for the correct dia to hand seat bullets due to the case taper.

[montana_charlie]

When a cartridge is fired, the case swells up to fit the chamber.
There is only so much brass in there, so when a BPCR case gets fatter ... it also gets shorter.
When you full-length resize that case it gets long, again.

If you don't resize at all, and your bullets are sized to fit the case mouth as it comes from the chamber, you can have cases that fully fit your chamber ... which never change.

I have a 'set' of cases I use for developing loads and they have all been fired 30 times with no failures.

CM

[kokomokid]

Thanks for the input. Im currently shooting fire formed brass with dropped in bullets. My gun is shooting best with about .020 bullet jump and i am going to try neck tension but my bullet concentricity is NOT what it should be.

[martinibelgian]

You cannot measure bullet concentricity on a loose-seated bullet in a fireformed case - It will only start aligning when being chambered. which is why most loads with a slip-fit bullet usually shoot best with the bullet hard into the rifling: best alignment to the bore, and good initial resistance when that primer ignites.

[MT Chambers]

I full length resize my hunting loads in 45/70 but not for my single shot, I use my Redding(of course) dies for sizing and a Vickerman in-line seater to seat the bullets. For the Marlin 45/70 I finish with a solid crimp from the Redding(of course) dies.

[GoodOlBoy]

I FL size 45-70 brass the first time I use it. Afterwards it is neck sized only since it is all shot through the same rifle afterwards.

GoodOlBoy

[rfd]

When a cartridge is fired, the case swells up to fit the chamber.
There is only so much brass in there, so when a BPCR case gets fatter ... it also gets shorter.
When you full-length resize that case it gets long, again.

If you don't resize at all, and your bullets are sized to fit the case mouth as it comes from the chamber, you can have cases that fully fit your chamber ... which never change.

I have a 'set' of cases I use for developing loads and they have all been fired 30 times with no failures.

CM

+1 ..................

[kokomokid]

Thanks everyone, Think i found my problem by checking runout at each stage useing different sizers and expanders. Problem being the expander.

[Ramar]

martinibelgian said:
"You cannot measure bullet concentricity on a loose-seated bullet in a fireformed case - It will only start aligning when being chambered. which is why most loads with a slip-fit bullet usually shoot best with the bullet hard into the rifling: best alignment to the bore, and good initial resistance when that primer ignites."

Now the secret's out and my #1 ranking I suspect is now going to be seriously challenged.
Ain't Nothing sacred???
Ramar

[EDG]

RCBS			NECK	SHOULDER	BASE
Cartridge	Code	Brand	TYPE	DIAMETER	DIAMETER	DIAMETER
.45-70		LEE	FL	.4735		.5040
.45-70		RCBS	FL	.4680		.4990
.45-70		Redding	Neck	.4680		.5090
.45-70		RCBS	FL	.4670		.5020
.45-70		Redding	FL	.4650		.5020

I have more than one 45-70 so I try to full lenght size but the largest die that I have. I have several 45-70 FL sizers.
A late model RCBS FL and a Lee FL have the largest interiors. I also check a RCBS 1972 sizer that I think is too small.

A bushing die or a lapped out FL die would probably be the best alternatives.
Here are the neck diameters of my 45-70 dies. The various dies have an internal step that defines the bottom of the neck.
The older RCBS die (.468 inside the neck) has a very long neck section that sizes deep into the case body.
The newer RCBS die (.467 inside die) has a shorter neck and sizes the case body less.
The Redding FL die has a very short neck that would leave a gas check hanging out in the wind with a 400 grn bullet seated to 336 Marlin length.

[Lumpy grits]

I do a 'lite' FL size. That is, I only reduce the case's OD .002-.003".
I ck and my ave run-out shows a TIR of .003" or less. I run just under .002 neck tension on my grease groove bullets.
Use a Lyman size die and a Redding seating die.
Load on a Dillon 550.
LG

[kokomokid]

I was using a pacific sizer screwed out three turns. I have gone to FL size rcbs and run a .456 M die expander followed by .458 expander. This gave me runout of .003 and less with neck tension of .001. Was using redding seater and according to their website 98% of runout problems were created before bullet seating.
May try one of BAC custom expanders to cut out a step. These shot a little smaller groups than unsized thumb seated rounds yesterday.

[EDG]

My best results happen with a .460 expander and a .460 bullet.
The brass spring back gives a slight friction fit.
I am sure that if I lapped my die out so the expander only opened the case .001 the results might be even better.