Subsonic 45/70 Through a Ti-rant .45?

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goteron
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Subsonic 45/70 Through a Ti-rant .45?

Post by goteron »

Thinking about building a Marlin 1895 in 45/70. Could I use my Ti-rant .45 for subsonic use only?

With that being said, what bullet (non-lead as my tirant is sealed) could I use to reload?

Has anyone done this or have load data for it?

Thanks
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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by JohnInNH »

I think a 45 cal LEAD bullet friendly Silencer that could handle a 535 gr bullet at 1150 FPS would be perfect. Like a Mystic and SS Sparrow combined (the clam shells)

I do not think most 45 ACP silencers can handle the pressure and volume of gasses you need for a 500 gr bullet

I have had the same desire.. The lever guns in 45-70 are SCREAMING to be threaded, but for what? I suspect an Osprey or TiRant would not fair to well.


I feel it is better then the 50 bore since you can load supersonic loads that are shootable with main stream brass.

I want to shoot the lower bullet at 1050 fps it is the 535 gr Postell bullet .. a 1000 yard winner at only 1450 fps. Stability will not be a problem in the 45-70.

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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by goteron »

John, thanks for the info.

I guess I'll look at a .44 special lever gun then. I was hoping for a heavy bullet lever gun with a pistol can.
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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by goteron »

Any word from AAC on this?

Can a tirant handle a subsonic 45/70 400g bullet from a 16" barrel? Would lead be a problem?
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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by jaredr »

goteron wrote:Thinking about building a Marlin 1895 in 45/70. Could I use my Ti-rant .45 for subsonic use only?

With that being said, what bullet (non-lead as my tirant is sealed) could I use to reload?

Has anyone done this or have load data for it?

Thanks
might be worth trying a remington 300 gr semi-jacketed hollow point, but if you don't already have an 1895 for load development not sure it's worth buying the rifle just to see if you can make it work.

hodgdon's published data for 300gr LFP shows 14 gr of trail boss for 1199 fps. I've head good experience with 15-20% below published Trail Boss starting loads but that was using lead projectiles, jacketed bullets likely not so forgiving of a long rifle barrel and low pressures.
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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by goteron »

Anyone from AAC on this. The Tax free weekend is getting close!
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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by JohnInNH »

http://www.silencertalk.com/forum3/view ... =2&t=75977

Look at some of my #s in my last post in the link above.
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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by goteron »

Well that looks fine then:

Quote

45-70 I get about 3,065 to 3,375 psi & powder volume about 14-25 gr for a 535 gr bullet in a 14" barrel.

MP= 2973 psi for a 45ACP 5" barrel powder = 6 gr

End Quote

So Bumping from 14" to 18.5" Barrel and shooting a 405g sub I should be fine. I would use the can for subsonic only.

Next question is which bullet to use. I would prefer to stay away from lead, but it seems non-lead 45-70 bullets are hard to come by.

I would only use the can for subs.

AAC, can I get an official ruling?
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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by JohnInNH »

goteron wrote:Well that looks fine then:

Quote

45-70 I get about 3,065 to 3,375 psi & powder volume about 14-25 gr for a 535 gr bullet in a 14" barrel.

MP= 2973 psi for a 45ACP 5" barrel powder = 6 gr

End Quote

So Bumping from 14" to 18.5" Barrel and shooting a 405g sub I should be fine. I would use the can for subsonic only.

Next question is which bullet to use. I would prefer to stay away from lead, but it seems non-lead 45-70 bullets are hard to come by.

I would only use the can for subs.

AAC, can I get an official ruling?
Wooo nelly.. I did not say that. It is not JUST about MP but VOLUME of gas too. 6 gr vs 24 gr is a lot of powder difference.

Just an FYI .. What works so well in a 10 barrel with a 535 gr bullet is a bunch different with a 405 gr bullet in an 18.5" barrel.

"but in a 10" barrel 5,000 psi 24 gr IMR 4227 (535 gr bullet) for 1048 FPS" This works because the barrel is only 10"

In a longer barrel it will be supersonic by a bunch. Now make it a 405 and a long barrel you have a real case capacity problem. If you back the charge down and lighten the bullet the chamber pressure is inadequate for a good burn. So you have to go to a faster powder to get the chamber pressure up. That creates another bunch of issues.

Good possibility that if you got a load that worked well in the 45-70 with a 405 the TiRant may handle it,, but AAC owns if the can can handle the increased gas volume.

A 45 Long colt is a much better case for a .45 in a rifle bullets to 300 gr.

When trying to develop a subsonic load a heavier bullet will help by doing 2 things.. 1) it will take up more case capacity., 2) it will bump up the chamber pressure so you get a good burn. Powders are designed to burn correctly at certain pressures.

A short barrel also does 2 things for subs. 1) more consistent FPS due to the drag on the bullet after the fast burn powder pressure drops off so fast. 2) lets you use MORE powder w/o going supersonic .. increasing the chamber pressure you can get.

The 45-70 load I had above only works in the 10" barrel.. the 14 it will be transonic. in a 16 it is supersonic.. the pressure is just right at 10" with 24 gr.. if you adjust the powder down to keep it subsonic in a 14" barrel the pressure is starting to get low and the % of powder burned and the consistency of the burn is not as good.. at 16" you have to reduce ti to the point you HAVE to go to a faster powder to get the pressure up.. Now you have to much empty space.

Just thought I would share this to help with load development. It really shows how a SBR can be a real good thing!
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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by goteron »

John,

Thanks for the information. I don't reload so I thought that capactity was the charge.

I have no interest in really getting into load development. I would ideally like to find 1 load I can work with for a while. I would like a bullet in the 400g range.

I guess I am lost on how gas volume would affect the can. Wouldnt this be the amount of time the pressure is acting on it? Like an impulse?

Forgive my lack of knowledge on Internal Ballistics. It seems that volume would only affect the sound reduction capability.

If I was going to use a 300g bullet I would just use a 300BLK. And I would be happy to do that if they made 300BLK in a lever gun format.

Are there any other options for a lever get with bullets heavier than 300g that I can use with a pistol can?
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Re: Subsonic & history of black powder

Post by JohnInNH »

No problem.. It is a dilemma..


Long read...

We have a "speed limit" and I will pick 1050 FPS as the upper limit, with 1000 being a little quieter... We want enough umph as we can get w/o picking a huge PITA round to load. So where do we go? We look for a big fat bullet loaded at the slowest speed we can find commercially..

That usually is a round developed for usage with black powder.. Back in the days where there was no replacement for displacement.

The 45 Long colt, the 45-70 would be the best.. followed by 44 cal.. 44 Spl and 44 mag.. Followed by even the 38/357...

Even the 44mag has to much case capacity for use with smokeless powder at our self imposed speed limit.

The other problem we have to look at is rate of twist . Since the 45-70 was made to shoot 500 gr bullets at about 1400 fps going down to 1050 is not that much of a drop.. But for the smaller bore diameters when we go as heavy as we can the twist is usually for a rifle bullet over 2300 fps. Slow them down to our speed limit and we can have stability problems. In the 308 we need to go to 1:8 up from the 1:12

So we go back to the older slower rounds.. the 45-70 again seems to be the best bore dia excluding the .50. We have 500-535 gr .45 cal bullets available at the top end and you can cast them.. too. A hell of a lot cheaper than jacketed .50 bullets.

The best way to make the larger old black powder cases work is to fill them up with bullet instead of powder. That is why I used the 250 gr bullets and 230 gr wadcutter in my 357 Maximum.. those bullets took up a lot of case space. I really wanted 300 gr bullets but was twist limited.

If we use the 500+ gr bullets and seat them deep we can use a higher % of the case capacity and by doing this we get a better, higher, pressure for the powder to operate at while staying at our self imposed speed limit. We have no need for barrels longer than 16" and really not even that... So the SBR is the platform of choice. We really do not need more than 12". 5"- 9" works well with most rounds.

Personally I am looking for a .44 or .45 bore rifle or SBR myself. I wanted the .357 cal as I felt the big 300 gr bullets would work well.. but I was running into twist and host problems.. a T/C SBR may be the answer with a fast twist barrel. Then I could easily add a .44 or 45 long colt or even 45-70 to my collection later on.

The 45 acp is the smokeless version of the 45 Long Colt. A massive case full of black powder is now replaced by a messily 6 gr of smokeless powder.

When using such small amounts of powder in such a large case you can have problems. Ignition problems, position sensitivity and very wide FPS variations to name a few.

Most people do not want what we, the silencer community, wants. The 300 BLK is really the first mainstream subsonic round offered in smokeless.

"Fast Twist", heavy bullets, and reduced case capacity, are all things we need. Add to that the desire to shoot cheap cast bullets we add a whole new bunch of problems to the mix.

Not hard enough.. Let's make that even more complex add in the semi auto functionality problems. If you never plan on shooting cast bullets and do not mind bottle neck cases than the 357 Gremlin is a good choice also the 338 specter, 300 blk, We really only have ONE choice for commercial that is the BLK. IMHO for pure subsonic usage the .30 is just a little on the small side.

Go back to the black powder "speed limits", which is faster than subsonic, and the best bore dia was 44 and larger.

"No replacement for displacement" is just as valid today in the subsonic arena as it was back in the day of the 45-70.
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Re: Subsonic 45/70 Through a Ti-rant .45?

Post by goteron »

John,

Thanks for all of the information.

I just got an email from AAC. No go on subsonic 45/70 through a Tirant. Guess it will be a .38 special through the Ti-Rant 9 then.
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