Need some education - neck sizing on a 45/70 Gpvt. cartridge - accepted methods?

[bedbugbilly]

This may well be an ignorant question, but, since I have been wondering about it I will ask it.

I am getting set up to reload 45/70 with BP. Just for general shooting/plinking/fun – no competition or long distance shooting. I’m still looking for a rifle – looking for a Springfield trapdoor or ?? – but a single shot. I will be starting out with one of the Lee .459-405-HB molds. My dies are a set of Lee dies I purchased from a member here – one of which is a compression die. I have ordered a variety of expansion plugs since supplies are short and I could get them in case I ended up with other molds/diameters and since they are fairly cheap – not a great expense to have if needed.

So – I will discuss two options on reloading and please tell me which will work or suggest a better way –
I have been able to get some used but good 45/70 cases and to start out, I will FL size them before first loading. Once fired in a single shot – I see no reason to FL size them, so my plans are to just size the cartridge mouth/neck area after firing, expand and seat the cast bullet. I have a Lyman 45/70 taper crimp die and I’m thinking a light taper crimp to make sure the bullet stays in place but not an “over crimp” – for want of a better way of putting it.

With that in mind – the 45/70 case has a base diameter of .505 and a mouth diameter of .480 – in other words – tapered case. So, after the initial first FL sizing, loading and firing, what is the best way to resize the case mouth/neck to the depth of bullet seating? When I reload my 45 Colt/or Schofield, after initial FL sizing, loading and firing – I just resize the mouth of the cartridge only down to the depth of the seated bullet. Since a 45 Colt case has a diameter of .480, is it feasible to set a 45 Colt FL die (minus de-capping pin) up high in the press and just raise the mouth of the 45/70 casing up into it to the depth of bullet seating? I don’t see how a 45/70 FL die – setting it high like you would for a bottleneck to just size the neck, could possibly resize the mouth of the casing to the depth of bullet seating.

OR – is it necessary to resize the neck at all? After the initial FL sizing, loading and firing of the cartridge – if for example – the diameter of the bullet is .459, will the case mouth ID not be .459 after firing? Or will it be larger depending on the dimensions of the chamber which might make it necessary to resize the neck of the casing? How much neck tension do you need to hold the cast bullet in place on top of the compressed load? Once the case is fire formed to the chamber, when reloaded, can the case be loaded with the BP, compressed and then a new lubed bullet be thumb seated on top of the charge – or seated with the seating die – and then be lightly taper crimped to hold the bullet in place?

In thinking about how or if to neck size, I thought of something like the Lee neck collet die – but I am assuming that if they make one for a 45/70 – it would be to neck size for the more common .457 diameter bullet – i.e. it would reduce the ID of the neck to less than .457 and then require an expanding plug to resize the ID to provide the correct neck tension of the size bullet you are using. Resizing a neck for that and then having to expand for a .459, .460 or similar cast bullet seems like overworking the neck?

Can someone educate me on what the accepted practice is for dealing with the neck of the 45/70 and cast bullets – resize – don’t resize, etc.? I’m trying to get the accepted method in my mind to know if I need to be looking at an additional die to perform the task?

Thanks.

Jim

[JKR]

You’ll get good advise here from people way more qualified than me. I started out full length sizing then went to neck sizing, then to not sizing at all. The only dies I use now is the compression die and the taper crimp. I’ve been using just enough crimp to hold the bullet from falling out. I can easily turn it. My rifle seems happy with this combination.
JKR

[Don McDowell]

A bunch of variables here. Not all 45-70 chambers are the same. But if a person uses a grease groove bullet big enough in diameter to firmly fit in a fired case, then no resizing is necessary.
With paper patch bullets I resize the fired cases, and then use an expander that opens the case up about .001 over the patched bullet diameter.

[bedbugbilly]

Thank you - greatly appreciated!

I figured it would probably be a "wait and see" - "trial and error" depending on the chamber in whatever rifle I end up with. IIRC - I read a post on here where one fellow talked about after loading, running the cartridge back up into the FL sizing die - at the time, it surprised me - but if everything was kosher on it - I guess with the tapered case if it fit in the die it would "snug up the neck" on the bullet. I'm looking to spend sometime weighing up charges of 2F - seeing what fits in the casing and on which I can get a moderate compression on the load and get the bullet seated tight to the powder charge. Fron what i have read, I doubt that I will be using a full 70 grain load that requires a lot of compression in regards to the toe of plinking and shooting I want to do.

Your advice and descriptions have been a great help to get it in my mind on how to approach it - hopefully once fired it will work out so that I can compress the load and then thumb seat and use the taper die if needed. If not - then it will be "trial and error" time but figuring out what is going to work best is half the fun.


Thank you - greatly appreciated. I will be copying off the responses to add to my reloading notebook for reference - that's what is so great about this site - lots of experienced folks who are willing to help and mentor!

[Don McDowell]

The powder charge will end up being what ever the target and the rifle tell you is the best. Some powders do very well with compression and plenty of it , others not so much. Schuetzen powder is one that absolutely hates compression. Most Goex powders do much better with compression. Swiss can work compressed or not. But again it all comes down to what the target and rifle tell you.

[Lead pot]

The problem with tightening the case neck with a bullet seated you are also compressing the portion of the bullet in the case making it smaller.
The best way is like Don said. I only use a full-length sizing die on new cases after annealing them before the first firing.
From then on in my standard chambers if I need to reduce the case neck I use a neck sizing die or a taper crimp die before I charge the case with powder and before I seat the bullet. But doing this you need to have the brass the same length or you will have loose or tight case mouths.
Or you can do what Don said, size then and then expand the case mouth to fit the bullet.

[tnlonghunter]

You’ll get good advise here from people way more qualified than me. I started out full length sizing then went to neck sizing, then to not sizing at all. The only dies I use now is the compression die and the taper crimp. I’ve been using just enough crimp to hold the bullet from falling out. I can easily turn it. My rifle seems happy with this combination.
JKRI pretty much do the same for my Pedersoli Sharps. I found that it needs some neck tension for good accuracy, so I taper crimp slightly. However, upon firing, the case mouth expands back to bullet diameter, .459" in my case. So after cleaning and annealing, charge, compress, thumb seat the bullet and taper crimp.

Sent from my SM-G973U using Tapatalk

[indian joe]

You’ll get good advise here from people way more qualified than me. I started out full length sizing then went to neck sizing, then to not sizing at all. The only dies I use now is the compression die and the taper crimp. I’ve been using just enough crimp to hold the bullet from falling out. I can easily turn it. My rifle seems happy with this combination.
JKR

I second this !! But by the look of your post you already got a good system figured out (comments here for a Chiappa 1876 with a .457 bore)
only need to size the body of a case if it wont chamber comfortably - and same for neck size. Most commercial die sets reduce the neck waaaaayyy too small then expand it back out so there is neck tension on the boolit --not needed with lead boolit and blackpowder . I use that LEE 459-405 and I use a .460 size die on the Chiappa - same boolit in a Uberti 45/75 I run through a .462 die (just in case there some lumps and bumps or a fat boolit - they come out of the mold .4615 - .462 and shoot fine unsized) the Yuberti is a little bigger bore (pedersoli barrel)
I modded the LEE mold - shortened the nose a little to get the meplat bigger than the primer pocket and took the HB tit off the base plug so its a flat base - use a 45thou HDPE wad over the powder - its a good shooter out to medium range (havent tested past 300yards)

[GregLaROCHE]

If empty brass chambers easily, I don’t see any reason to full length resize. If your boolit fits in the case easily there’s no need to expand it. Annealing when you first get them won’t hurt. Especially if you need to expand the necks to fit your boolits in the first time. After being fired in your gun, the necks shouldn’t need to be resized, only a lite taper crimp to keep the boolit in place. If the boolit won’t fit in the case after it was fired in your gun, consider resizing it smaller.

If you have a standard modern chamber, you will have to seat the boolit deep in the case to not exceed the overall length capacity of the chamber. This makes it difficult to get enough BP into the case. A lot of people like to use a drop tube and then compress the powder to improve its burning and get the most possible in. When compressing, be sure not to use too much force causing the case to bulge.

If I were buying a single shot, I would want one with an extended chamber, so boolits can be seated much further out. That way you will be able to load 70 grains of BP and maybe a wad or grease cookie too. Maybe even consider a 45/90.

Consider slugging your new gun as soon as you get it to have an idea of best diameter to size your boolits to.

Don’t forget you need to clean the gun after each use. BP is very corrosive. I like to fire a smokies load as my last shot. I think it makes clean up easier.

Good luck and let us know what you end up buying.

[JKR]

When I sized cases I annealed case necks for every reloading. Now that I no longer size, is there any reason to anneal at all?
JKR

[Castaway]

Play with powder charge and compression so that the bullet chambers and the nose of bullet engages the rifling. No need to size at all, just thumb seat the bullet into the case

[semtav]

When I sized cases I annealed case necks for every reloading. Now that I no longer size, is there any reason to anneal at all?
JKR

you'll get all sorts of answers for that. My 45-110 that is shooting so well, I anneal after every firing and will continue to do so. Just decided to start doing that for all my cartridges regardless. I never size my brass any more either.

[tmanbuckhunter]

I don't size BPCR cases at all. Haven't found a need and it seems to hurt more than it helps.

[rjmelehan]

The powder charge will end up being what ever the target and the rifle tell you is the best. Some powders do very well with compression and plenty of it , others not so much. Schuetzen powder is one that absolutely hates compression. Most Goex powders do much better with compression. Swiss can work compressed or not. But again it all comes down to what the target and rifle tell you.

What Don said..!

I have a well healed friend who has a collection of rifles that would make the Smithonian blush.

He sends me a rifle or two from time to time to do a load workup (my passion)
One Rifle happened to be a Browning 78 45-70 1885 HiWall, custom barrel w, wedding ring.

As I have several moulds for that cartridge
I take a given mould and start with 30/1, 20/1 etc, then depending on the results I will charge with no compression all the way up to .1
(Swiss 2F)
Next step has to do with your case sizing question:
First load is always full length sized, Next is neck only, then no sizing, then breach seating.

My final load for this rifle shot 1" groups (regularly) The target I sent back with the rifle and load data / mould & specs had 20 shots in 1 inch @ 100 yards (with the exception of the cold bore fouling shot)....Punch line, this rifle liked that bullet over Full Length Sized cases

In all of my 40 years of experimenting, I've determined there is no set answer for any given BPCR rifle.
Starting points, sure but the rifle will have to tell you what it likes.

That being said, I am a novice compared to many.

Post Script:
In some situations where I thought a given design, say a 457125, would work perfectly because the nose and driving bans were a great fit, only to find that no matter how soft or hard the mix was I couldn't get it to shoot, then other mould designs that thought would not work ended up being great.

Suggestion:
Paul Mathews has 4 small books on BPCR which were a good starting point for me.

Some Starting points for me when developing loads for Black

Swiss 2F
Pistol primers
News paper disk over primer
SPG type lube (make my own similar, Paul Mathews formula)
Drop tube all charges
wax board of some sort (usually a milk carton) or grease cookie over all charges. (if not wiping between shots)
For load development I use a scope then switch to vernier