I have the load data for 410 Subx bullets with tight group. I am prob gonna use those to hunt with. I want some 500gr plinking rounds to mess with and show off the quiet heavy hitter. I have a few bottles of tightgroup (preferred powder) and 2 small bottles of trailboss (would prefer to save rather than plink with). Either way my thought was to start at the 410 grain 13 grains of Tightgroup load from hogden in the 500 grain lead rounds. I figure it may put me at or a little over subsonic and I can go down from there.
45-70 subsonic loads
- Thread starter Sigfla
- Start date
dellet
Gold $$ Contributor
Depends on the rifle, but probably not the best plan.
The likelihood of that load being over subsonic velocities is out weighed by the likelihood it will be over pressure.
Honestly about half of Hodgdon data for the 45-70 is questionable at best and unsafe for Trapdoor and early rifles. Generally the three pressure levels for 45-70 are 20,000 psi for trapdoor rifles, 30,000 for modern lever actions, 40,000 for strong actions. The 410 grain bullet load is estimated at 28,000 psi. Probably half the rifles on the market, are questionable at that pressure. Note that Hodgdon lists the same pressure limits for trapdoor and lever actions.
Adding 100 grains of bullet weight without reducing charge weight will probably push the pressure near 40,000 psi. Depends on your rifle.
Ruger #1, Winchester Miroku 1885, Marlin lever actions no problem.
All this is complicated by the fact everyone’s go to first sign of pressure is flattened primers. In the case of the 45-70 and other black powder cartridges, trying to read a primer rated for 2-3 times the pressure that the action blows up in your face, is counter productive.
You might look at some other data, but generally heavy bullets with trapdoor rated pressures, will be sub sonic.
The likelihood of that load being over subsonic velocities is out weighed by the likelihood it will be over pressure.
Honestly about half of Hodgdon data for the 45-70 is questionable at best and unsafe for Trapdoor and early rifles. Generally the three pressure levels for 45-70 are 20,000 psi for trapdoor rifles, 30,000 for modern lever actions, 40,000 for strong actions. The 410 grain bullet load is estimated at 28,000 psi. Probably half the rifles on the market, are questionable at that pressure. Note that Hodgdon lists the same pressure limits for trapdoor and lever actions.
Adding 100 grains of bullet weight without reducing charge weight will probably push the pressure near 40,000 psi. Depends on your rifle.
Ruger #1, Winchester Miroku 1885, Marlin lever actions no problem.
All this is complicated by the fact everyone’s go to first sign of pressure is flattened primers. In the case of the 45-70 and other black powder cartridges, trying to read a primer rated for 2-3 times the pressure that the action blows up in your face, is counter productive.
You might look at some other data, but generally heavy bullets with trapdoor rated pressures, will be sub sonic.
nakneker
Gold $$ Contributor
I’ve been using a lot of AA5744 is sub loads and mid range loads in quite a few big bore cartridges. It works great in the 45-70 albeit hard to find right now. Below is a link from UR Reloader that or may not help, they use the bullet you mentioned with 5744 and IMR 4895 which should be easy to get. Recently Trail boss hit the market it again but it went fast but if you see 5744 it’s a great option. It’s also not position sensitive in the case which is something I like a lot. I’m using it 45-70, 444 Marlin, 45 Colt, 44 mag and 38-55.
www.bing.com
AA5744 45-70 subsonic load - Search Videos
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It’s a TC encore with a 16” custom fast twist MGM heavy barrel.
dellet
Gold $$ Contributor
I would stay away from the Ruger/strong action loads, too many other good loads available, without risking long term damage to the contender.
The titegroup load is not something I would do without running some models because it barely make velocity with a 410 grain bullet, and will only get slower with a higher pressure with the 500 grain bullet. Then since you have a 16” barrel, you’ll need to add more powder to make up for the velocity drop, unless you want to shoot at 900 fps.
Basically any load you find around 1300 fps in a 24” barrel, normal for published data, is a potential sub load. That opens up a lot of combinations. Just be mindful of ultra fast powders and trying to reach published velocities.
The titegroup load is not something I would do without running some models because it barely make velocity with a 410 grain bullet, and will only get slower with a higher pressure with the 500 grain bullet. Then since you have a 16” barrel, you’ll need to add more powder to make up for the velocity drop, unless you want to shoot at 900 fps.
Basically any load you find around 1300 fps in a 24” barrel, normal for published data, is a potential sub load. That opens up a lot of combinations. Just be mindful of ultra fast powders and trying to reach published velocities.
I figure my encore is almost as strong as the Ruger. If it was a contender then no. It’s for sure stronger than a lever gun. I am shooting cast so I am not super worried about pressure. Bullet manufacturer suggested I start at 11 grains and go from there. I want to drop powder with my RCBS lil dandy so I have the rotors to do it fairly easy. I did go ahead and buy some 405’s at .459 diameter to use as well since the data is all over for those.
What’s the twist on that gun? Over 20?
Internet says 18. Seems like 500’s should stabilize. I am no cast expert but others suggests I go to a .459 bullet to avoid that issue. You may need .459 or larger. I saw one guy on the cast forum go over .460 I think he slugged his barrel to .470.
Barman54
Silver $$ Contributor
Thx,
They do Stabilize, they have to be going FAST, using 5744, I4198, 2015.
I do Size my Boolits to .459, after P/Coating them.
418, 405,350, 300 grainers I do use P. Powder to be Sub-Sonic.
Those Postell Boolets are a Hunk of Lead!
Load for a Uberti 1886, another Fun Gun in Caliber.
Out
They do Stabilize, they have to be going FAST, using 5744, I4198, 2015.
I do Size my Boolits to .459, after P/Coating them.
418, 405,350, 300 grainers I do use P. Powder to be Sub-Sonic.
Those Postell Boolets are a Hunk of Lead!
Load for a Uberti 1886, another Fun Gun in Caliber.
Out
figured I would toss in my info. I have a Marlin Dark 45-70. 16". I think 1:20 twist.
I've been loading 340-500gr bullets. Started with Berrys 340gr, moved into casting my own bullets and powder coating them. Have a few molds now:
Lee 340gr 457-340-F
Lyman 405gr 457193
Lyman 480gr GC 457406GC
MP molds 462-420HP 4 cavity plain base 405gr solid, or 388gr penta hollow point (my main go to mold now).
most of my loads are around 950-1050fps. I've been using mostly VV 3N37 (12-13gr) and some N320 (I'd have to go back and look but around 10-11gr). also tested Titegroup (not a fan in this application, got SD/ES all over the place), and some 4227 (19-21gr I think).
my main load right now is 12.5gr 3N37 under the 390gr HP cast/powder coated bullets. Shoots right around 975fps out of my Dark 16".
in the photo left to right- Berrys 340gr, Lee 340gr (blue), MP mold uncoated 390gr HP, MP 390gr HP (pink coated), Lyman 480gr GC red PC.
I've been loading 340-500gr bullets. Started with Berrys 340gr, moved into casting my own bullets and powder coating them. Have a few molds now:
Lee 340gr 457-340-F
Lyman 405gr 457193
Lyman 480gr GC 457406GC
MP molds 462-420HP 4 cavity plain base 405gr solid, or 388gr penta hollow point (my main go to mold now).
most of my loads are around 950-1050fps. I've been using mostly VV 3N37 (12-13gr) and some N320 (I'd have to go back and look but around 10-11gr). also tested Titegroup (not a fan in this application, got SD/ES all over the place), and some 4227 (19-21gr I think).
my main load right now is 12.5gr 3N37 under the 390gr HP cast/powder coated bullets. Shoots right around 975fps out of my Dark 16".
in the photo left to right- Berrys 340gr, Lee 340gr (blue), MP mold uncoated 390gr HP, MP 390gr HP (pink coated), Lyman 480gr GC red PC.
Attachments
also these are all shot out of the Marlin Dark through a Dead Air primal 46 caliber can. No issues with keyholing or stability with any of them at subsonic velocities. I shoot the Berrys with some 3031 at faster speeds, they all do fine and are stable at higher speeds as well.
Rifle is Marlin Dark (Ruger made), Leupold FX-II 2.5x scout scope, Timney trigger, Emissary Development Handbrake, DA Primal. Love this thing.
Rifle is Marlin Dark (Ruger made), Leupold FX-II 2.5x scout scope, Timney trigger, Emissary Development Handbrake, DA Primal. Love this thing.
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