Rio Grande 45-70

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SoCal44
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Re: Rio Grande 45-70

Post by SoCal44 »

give me a list of the bullets you are going to use and their length plus the cartridge OAL that you are going to use with each bullet
The LaserCast 350 gr. is .909 in length. The Missouri Bullets 405 gr. is still en route. The powders I'll soon have (on the way from Powder Valley) are H4198, H335 and Ramshot X-terminator. I was planning on seating @ 2.100, the Hornady manual lists the COL as 2.105.

Thanks
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Re: Rio Grande 45-70

Post by Ranch Dog »

SoCal44 wrote: I was planning on seating @ 2.100, the Hornady manual lists the COL as 2.105.
SoCal... something is up with the OAL. It should be around 2.5XX", not 2.10X". You might just wait until you have bullets in had and make some dummy cartridges you are happy with.

I did the H335 testing with my rifle and my 300-grain bullet, up to 35.3K PSI. I started investigating some loose groups and PSI/FPS slightly less than expected, going back and checking everything from the beginning. My cartridge OAL is wrong. I was using 2.420" and it should be 2.520! Checked it three times and don't know how I messed this up. I'm going to close that gap between bullet and bore and the PSI/FPS should hit target along with a tighter group. I'm also going to size my bullet down from .460" to .458" and try them against each other.
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Re: Rio Grande 45-70

Post by Ranch Dog »

SoCal44 wrote: I was planning on seating @ 2.100, the Hornady manual lists the COL as 2.105.
SoCal... something is up with the OAL. It should be around 2.5XX", not 2.10X". You might just wait until you have bullets in had and make some dummy cartridges you are happy with.

I did the H335 testing with my rifle and my 300-grain bullet, up to 35.3K PSI. I started investigating some loose groups and PSI/FPS slightly less than expected, going back and checking everything from the beginning. My cartridge OAL is wrong. I was using 2.420" and it should be 2.520! Checked it three times and don't know how I messed this up. I'm going to close that gap between bullet and bore and the PSI/FPS should hit target along with a tighter group. I'm also going to size my bullet down from .460" to .458" and try them against each other.
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SoCal44
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Re: Rio Grande 45-70

Post by SoCal44 »

Oops :o that'll teach me to read my manual without my glasses. I typed the max case length. Sorry 'bout that. It should have been 2.550 Max COL.
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Re: Rio Grande 45-70

Post by pricedo »

Ranch Dog wrote:
SoCal44 wrote:Can the Rio Grande 45-70 be safely loaded to the Marlin 1895 specs. (which I believe is < 40,000 CUP)? In my reloading manual I see Trapdoor loads, Marlin Levergun, and Ruger #1 loads. I'm assuming I can use the Marlin loads.
Here is my take on it. The RG4570 is a 336 clone not a 1895 Clone. The 1895 action has a little more beef where the receiver meets the barrel threads. That said, here is how I'm proceeding with my RG4570 based on my pressure trace testing experience.

When using that equipment, barrel outside diameter vs. chamber diameter and brass thickness are settings used to calibrate the strain gauge. Using the RG3030 as the "know"; with its pressure standard against and dimensions against those of the RG4570 I feel good in estimating, for my use, what the RG4570 is capable of.

I use CIP standards where I can as they relate directly to what I see with the strain gauge equipment. The 30-30 has a 46.4K PSI Pmax and 40.6K PSI NMP (Nominal Max Pressure). Loads are generated to NMP so that the variations can be contained within the PMax. Pressure, just like velocity, varies and nothing should exceed the max.

For my RG4570 I compared how much metal is around the chamber to how much metal was around the chamber of my RG3030 (now a 38-55), and I use 40.3K PSI as the Pmax and 35.3K PSI as NMP. The larger bore leaves less metal and there is no way the chamber can handle the same pressures that the 30-30 is being subjected to. What that is in CUP, I don't know. I can guess at it but use data with PSI results in my reloading. This 35K PSI target is not that far off of what I use in my Marlins. For the "G" I use a 48.0K PSI Pmax and 42.0K PSI NMP.

Using a 350-grain bullet as an example and with the above referenced pressures, I would expect to see about 100 FPS less in my RG4570 with the typical powders used in this cartridge. My Guide Gun would produce 2060 FPS and the RG4570 1960 FPS. That is still an amazing amount of killing authority.

All of us 45-70 shooters realize that we kind of operate outside the box at our own risk. Using Marlin 1895 data in the RG4570 is a bigger risk than I will take.
Everything in life is a trade off.
Do you think you got that pound or so less weight and better portability & "swingability" for nuthin.
Nope !........you didn't.
Rossi had to remove more steel from the generic (I'm assuming for cost reasons) barrel & chamber blank to make a .45-70 than they did to make a .30-30.
I'm confident that the cartridges in my RG .30-30 have plenty of steel around them to handle maximum loads in that caliber.
Again a trade off cause for the same reasons as stated above ..............the .30-30 rifle is heavier than .45-70 RG.
I'm an engineer though definitely not in the ballistics field but it's just good "horse sense" to assume that more steel wrapped around a detonating cartridge means higher pressure tolerances.
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Re: Rio Grande 45-70 - practical limits

Post by pricedo »

I think the RG .45-70 is good for just about any practical application.
If I was intent on exploring the maximum capabilities of the .45-70 cartridge I'd get a Pedersoli 71 in .45-70 or have a Browning BLR in .450 Marlin re-chambered to .45-70.
Both the 86/71/92 & BLR actions are good to 65K psi and should be able to handle published loads developed for the Ruger #1.
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Re: Rio Grande 45-70 - practical limits

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DELETED.........Off Topic
Last edited by pricedo on 25 Feb 2012 21:16, edited 1 time in total.
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SoCal44
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Re: Rio Grande 45-70

Post by SoCal44 »

This thread got sort of hijacked...I'm not concerned with pushing the 45/70 to it's Limits, Pedersoli rifles, Niel Jones, BLR rifles etc.....I was asking about safe loads for the Rio Grande in 45/70. So , back on topic.
Ranch Dog, I have received my bullets. Per your request the lengths are:
350 grain is .909
405 grain is 1.035
Thanks for your help
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Re: Rio Grande 45-70

Post by Ranch Dog »

SoCal,

This data is to be used at your own risk with normal, safe cartridge reloading practices! It is based on the following:
  • Brass 2.105"
  • Cartridge OAL 2.550"
  • 40.3K PSI Pmax and 35.3K PSI NMP
  • The maximum is the indicated charge or FPS, whichever is reached first!
Build a dummy cartridge with each bullet first and insure there isn't any feed issues. If any length changes, let me run it again.

Starting with the big dog first, the Missouri 405-grain bullet:
  • Ramshot X - 49.0-grains for 1815 FPS
  • H335 - 51.1-grains for 1810 FPS
  • H4198 - 41.6-grains for 1725 FPS
The LazerCast 350:
  • Ramshot X - 54.4-grains for 1990 FPS
  • H335 - 56.7-grains for 1975 FPS
  • H4198 - 46.2-grains for 1895 FPS
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SoCal44
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Re: Rio Grande 45-70

Post by SoCal44 »

Thanks for the load info Ranch Dog. Yesterday, I finally had the chance to get out and try some of your suggested loads. I was very impressed. The recoil was stout. I would compare the recoil to my Mossberg 500 18"bbl with slugs.
This Rio Grande is my first and only 45/70 (although I do have a Ruger No. 1 to pick up Friday). I really like this gun. The action is very smooth.
The loads I tried were:
50 gr. X-terminator w/ 350 gr. Laser-Cast.
56 gr. H335 w/ 350 gr Laser-Cast. This was near your max load of 56.7 grains. These were powerful!
45 gr. X-Terminator w/ 405 gr. Missouri Bullet.
and a load of my own- 37 gr. H4198 w/ 350 gr Laser-Cast. This was mild compared to the above.

On the 56 grain load mentioned above, I did see what I think are some pressure signs, see the picture. I don't know if this is enough to be concerned with. I would like to hear your opinion. The case on the right was the 56 grain load, the left was one of the 37 grain loads.

Again, thank you for your assistance & advice

SoCal44

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