45-70 Internal Ballistics

[McLernon]

Do any of you BC fans use machined cases so that the relatiivly small smokeless powder charges employed fill the case. I would think that if one uses the 'normal' cases meant for BP, that ignition problems might result. I am thinking of getting a 45-70 and I want to understand the internal ballistics with using smokless powders.
Thanks

McLernon

[moxgrove]

Using large rifle primers, I have never had any ignition problems using everything from a light dose of unique with a round ball for squirrels up to the beartooth pile drivers. The primer is hot enough to do the job. You might get inconsistent standard deviation, but I have never had any appreciable accuracy detriment. You could use 5744 which gives a good loading density. or go black powder. you could also experiment with dacron filler. I have never used th fillere and have been fine with my results. I'm sure other more knowledgable members than I will chime in as well. Don't worry too much or try supere heavy loads just to fill the case. I use a lot of 4198 for my 47/70 and have been happy. I prefer to throw heavy bullets a little faster than bp level . I no longer try to hot rod the 45/70. a 425 wfn at 1400 fps kills anything I hit right. That's all I can ask for and it is much more fun to shoot.

[Haywire Haywood]

Machined cases?

Ian

[TomP]

McLernon, I use 29 gr IMR 4198 with a 405 gr lead bullet in my 45/70 Buffalo Classic.  At one time I used a small tuft of cotton to hold the powder against the primer but later I decided that it didn't seem to make much difference.  I'm able to get 2 inch groups at 100 yards which is better than I can see.

I know that thick-walled cases machined from solid barstock have been used for cartridges like the 577-450 to reduce the huge volume, even for black powder.  But I've not heard of anyone needing machined cases for the 45/70.

[scrounger]

There is a company that makes and sells chamber inaerts so you can shoot .22 Hornet or .22LR in your .223, and .30 carbine in your .30-30. We should contact them and have them make us some chamber inserts for the .45-70 that would allow us to shoot .45 Colt cases or .45 ACP in them. The .45 Colt cartridge case will hold up to 25 grains of powder. Only problem is 25 grains of powder in the Colt case will generate higher pressure than an equal amount of powder in the .45-70 case. Maybe they would just produce some smaller capacity .45-70 cases for us out of steel. I have the company address around here somewhere.

[quickdtoo]

http://www.mcace.com/adapters.htm makes chamber adapters, but it you want to shoot .45Colt, just buy a 45Colt barrel next year, I'm sure shooting .452 bullets in a .452" bore will be much more accurate than in a .458" bore! And that's not addressing the issue of getting the spent case out of the chamber!!

Tim

[Lone Star]

Over a decade ago, several members of the Cast Bullet Association made low-volume cases for either .444 or .45-70 loads.  As I recall, they achieved great accuracy - but no better than what they could have achieved with normal cases and carefully developed loads.

There are several methods to achieve low ES with the .45-70.  One is to use a powder that fills the case to compression, like H4831.  Another is to use faster-burning powders (for low velocity loads only!) that bulk up well but ignite easily like Unique, BlueDot or 800-X.  Fillers used to be recommended but that practice is generally discouraged today - the risk of chamber damage is real if rare.  Lyman used to list numerous loads using case fillers like Dacron; their current manual lists zero loads with case fillers.  There is probably a good reason for that....

However, most of us find good accuracy using the loads listed in various published data.  I've loaded the .45-70 for over 30 years and have not seen the case capacity to be a detriment to accuracy.  OTOH, finding highly accurate .45-70 firearms is a different story.


.

[safetysheriff]

There are several methods to achieve low ES with the .45-70.  One is to use a powder that fills the case to compression, like H4831.  Another is to use faster-burning powders (for low velocity loads only!) that bulk up well but ignite easily like Unique, BlueDot or 800-X.  Fillers used to be recommended but that practice is generally discouraged today - the risk of chamber damage is real if rare.  Lyman used to list numerous loads using case fillers like Dacron; their current manual lists zero loads with case fillers.  There is probably a good reason for that....

using the slower powders, like Lone Star is indicating here, not only increases accuracy by way of increased load density, but also reduces recoil because they generate lower pressures and lower velocities.   some just can't understand that.

the reason that Lyman took the fillers out of their book is probably because such 'soft' fillers can create problems with straight-walled cases.   (they're safer with bottlenecks) if you want to reduce case volume you'd be better off experimenting with wads that are glued to the base of the bullet i'd think.....much like the wads that were/are screwed into the base of the shotgun slugs by Brenneke for the 12 gauge loads i've seen.

i recommend the slower powder, however, with a case-filling measure of it, before i'd bother with wads.

just my opinion and what i've seen in print,

ss' 

[Swampman]

I've seen some data for Trail Boss.  Perhaps it would fill the case better.  I've never had a problem with smokless powder in the .45-70.

[Joel]

The need for machined cases is imaginary.  I've shot the 45/70 for 15 years with various loads, and anything in the reloading manuals works fine.  In fact I've never heard of erratic ignition with this cartdridge, although I'm sure there's some "homebrew" out there that will do it.  Reloading manuals aren't in the habit of including such loads...wouldn't make much sense would it.  Stick to standard, tested loads and you'll be fine.  My old NEF will put any load using IMR 4198 for the lighter bullets(300/350) and RL7 for the heavier ones into 1 inch groups all day long. The target shows the 400 gr Speer FN behind 44.0 grs of RL7 for around 1950fps.  The top left shot is my fouling shot and the other one out of the group, and just below that one, is due to the guy next to me firing just as I squeezed the triigger. Considering I was just making sure the rifle was still sighted in, and wan't really trying to "benchrest" it, that's a decent target.

[Swampman]

Not trying to derail the topic, but does anyone else besides me think the 405 grain factory loads kick less than the 300 grain factory loads?  What is the velocity of the 405 grain Remington factorty load out of a 22" Handi? 

[45/70fan]

You're right, the 405's do kick less, they are only rated at 1330 fps. I haven't used them in a long time but I seem to remember them going about mid 1200's over the chrony.

[Swampman]

They are actually fun to shoot IMO.  405 Grains at 1250 still seems like it would ruin something's day.  I want to work up a similar load using Varget.  I'm not into loose teeth.

[turkeyeye]

I shot some of the factory Remington 405 grainers today.  They felt like shooting a 12 gauge with a field load.  Very pleasant to shoot.