subsonic 45/70

[Certified]

question for the reloaders here; I am looking for suggestions for a subsonic load for a 45/70. I plan to use Hornady 500 gr jacketed bullets. Barrel length is 16.5". I am thinking a fast powder so as not to produce to much gas volume as I would like it to be quiet also. And should i consider using a case filler as there will most likely be a lot of empty space in front of the primer.

[Cattle/Horses]

I'll bite - after looking at Hornady Bible Volume I I'd start by trying 22gr of IMR 4198. (25 grains pushes it at 1025 FPS).

I've seen an old timer put a little cotton on top of his load as a case filler. Have no idea how it works out - never had reason to try it. Mapper, do you have any experience using cotton as a case filler?

[JMW4570]

I've seen folks use some dacron filler. I bought a bag of biodegradable packing peanuts to use a filler but havent tried them yet. If you aren't going to use filler you might want to rock the case back before firing to pull the powder near the primer. I use 5744 for lower pressure 45-70 loads.

[mapper]

No experience using cotton/dacron as case filler, I do know that certain powders are sensitive to case position at various fill densities.
I don't load 45/70, but did run across some threads and subsonic loads ( think trapdoor ) using trailboss, since it is a bulky powder.

I'll see if I can find them. Most of the other load data I have seen is supersonic, and trailboss, or unique was not listed.
I also saw instructions on using trailboss with no known load data, based on bullet seating depth, and case volume.
http://www.imrpowder.com/PDF/Trail-Boss-data.pdf

I have only looked at it from a educational standpoint.
And most of what I saw was cast bullets, not jacketed.
https://thefiringline.com/forums/sho...d.php?t=422131

This one is about subsonic and 500 gr jacketed.
There are diffrent powders reccomended,
Lead pushes easier than jacketed, and I wouldn't want to stick a bullet in the bore.
https://thefiringline.com/forums/sho...d.php?t=480301

[FLT]

I start with a recommended load and reduce it a couple of tenths of a grain at the time and shoot it over a chronograph till I get down to subsonic . That way I don't risk getting a bullet stuck in the bore. If you work with trail boss powder you won't need a filler as it is very bulky and was designed for reduced loads.

[Certified]

i'll have to find my notes, but I have tried a couple of loads and got close but they were loud. I did try using foam ear plugs as case filler and the only noticeable effect was a 100 to 200 fps increase in muzzle velocity. The ear plugs were found intact on the ground down range. I just found some Trailboss, so that is going to be tried in the near future.
thanks for the ideas, mark.

[substratum]

As a teen in the 70s, I loaded a #0 buckshot (.320/49 grains) as a squib load in 8x57, and used a small piece of toilet paper to keep the powder close to the primer. I'd crimp the case slightly sans shot (not quite full stroke), and friction fit the shot in with a mallet tap because that was easy, and more importantly, didn't require me to change the crimp setting on the die. The load was apparently cool enough that it didn't fully ignite the paper, and some of it would flutter to the ground about 15' out the muzzle. I got the squib load and tissue idea from reading an article about squib loads for a .30-30, and extrapolated the load for the 8x57 based upon the case capacity they filled to in the .30-30 load (something like 10%). As I recall, it shot the paper pretty well at 25 yards with iron sights and was considerably quieter than a .22 LR. I kept a few in my pocket thinking they could be used on something smallish while hunting that didn't warrant a 196 grain bullet.

I'm thinking that a .45-70 subsonic load is still going to go *BOOM*.

[JMW4570]

Maybe if you would have used clean toilet paper it would have burned up...

[Certified]

I still need to dig out the notes for the load I did find to be subsonic, just real busy lately. The load that I worked up was grouping about an inch at 50 yds, going 1050 fps. with a pretty good boom. Certainly not full power boom, but you needed hearing protection. However when I ran that load through the can it gained speed and was running about 1200 fps. so I need to slow it down. Still made more noise than I want through the can.

[Certified]

had pretty good success at the range, 18g of 4198 and we are just subsonic. Rounds are grouping at 2" at 100 yds. attached is a video of shooting 100 yd steel plate.