Pressure Signs?

[choprzrul]

I have a modern Winchester 1885 in 45-70 and I'm getting ready to do load development. It occurred to me....I'm ok with identifying signs of pressure in bolt actions....but beyond primer dimples/ripples/flattening, are there unique signs of pressure I should be watching for in my 1885?

Some background parameters: Barnes 300gr TTSX over RL7 in a PMC case. Quickload is telling me 49,260psi at 50.5gr....which should be well within the strength of that 1885 action? Barnes uses 55,000psi for their Ruger #1 load data.

My goal is a minimum of 2200fps at the muzzle if possible.

 

[C_Ackley]

Looks like other powders can get you there within LeverGun load data pressures.

I'm assuming these are your bullets.

You have a pleasant advantage over the levers because you can seat that bullet basically to the lands since it doesn't have to cycle through an action. Which will reduce the pressures even further due to reclaimed case capacity.
Be careful, not sure I would consider the 1885 as synonymous with the Ruger No1 despite the action being basically the same, but it's without question stronger than levers.
God help your shoulder and I hope you have dental insurance, enjoy.

Edit: that load data is from Barnes website, data is for lever guns. What I notice that looks weird to me is the 2.515 COAL. That's really short and you could cycle the action with a 2.540 COAL, maybe there's a reason. Doesn't apply to your 1885 obviously.

 

[choprzrul]

Thank you for your reply C_Ackley.

Since my 1885 won't have bolt lift issues, or ejector signs on the case head....and I assume the case heads are all going to expand to the chamber limits and never exhibit case head growth....

Are there signs to look for that are specific to the single shot rifles?

.

 

[C_Ackley]

Are there signs to look for that are specific to the single shot rifles?

Definitely a question for the more experienced than I.

 

[gdbleb]

"are there unique signs of pressure I should be watching for in my 1885?"
Your shoulder!

More seriously -
I download mine as I just punch holes in paper.
Per the Sierra Book - Edition 5, Max load for strong action 45-70's is 53.3 gr of RE-7 giving 2100 fps.
Start 48.8 gr at 1950 FPS.
(adding) This for the Sierra 300 gr HP/FN bullet.

Its a fun gun. Browning's first design. Did it in his late teens - I think.

 

[choprzrul]

As measured with my Sinclair tool, that TTSX is touching the rifling at 2.759" Allowing for the typical Barnes jump, I'm starting development at 2.700" OAL. At that OAL, and using the 300gr TTSX, QL is telling me 50.5gr of RL7 has a 106.4% case fill. The lead Sierra's obviously are shorter and allow more case capacity....but I think 50.5 is about my max fill. QL says 2306fps at 50.5, so I have quite a bit of wiggle room to find a load at 2200fps or above I think.

But, yes, my shoulder will probably not be happy about all of this :-(

On a side note, RL7 seems to have the gentlest slope for whatever that might mean....

 

[mongo chicago]

I would not dare to put the 1885 in the same strength class as a Ruger #1. (I have owned both though not in 45-70). That being said any modern load from reloading manuals not specifically made for the Ruger should be safe in the Highwall.

 

[choprzrul]

I would not dare to put the 1885 in the same strength class as a Ruger #1. (I have owned both though not in 45-70). That being said any modern load from reloading manuals not specifically made for the Ruger should be safe in the Highwall.

Therein lies my question....what are the signs of pressure that I should be looking for in my 1885?

.

 

[choprzrul]

It occurs to me....Winchester offered that HiWall in 375 H&H magnum, which specs out at over 62,000psi. So....this would seem to suggest that a 55,000psi load should be within the design parameters of the action itself? Now.....how much will that 45-70 brass tolerate?

Which, of course, leads me back to my question....what are the signs of the brass being stressed from too much pressure in my 1885?

 

[DirtySteve]

I one time loaded my T/C Contender 45-70 to the point where it would auto eject... I had no pressure signs...

Having said that stick to the maximum in the manual for your rifle. The 45-70 is a work horse not a Quarter Horse. With a case as big as the 45-70 I think you will not get much in the way of warning signs prior to having a bad day.

 

[dellet]

You might want to compare bolt or in this case breech block thrust with some of the larger magnums that the Miroku 1885’s were chambered in. In theory it’s internal diameter, but the 45-70 might still be larger since it is a lower pressure case, thus a larger internal diameter.

SAAMI proof loads are about 40,000 PSI, so the question is whether the brass manufacturers are over engineering or not.

You will get flattened primers just like any thing else, and if you get to the point of sticky extraction, you’ve gone way to far. Measuring case heads works.

You should be able to neck size.

Depending on chamber sizing a bulge above the web is a place I don’t like to be.

 

[LCazador]

Thank you for your reply C_Ackley.

Since my 1885 won't have bolt lift issues, or ejector signs on the case head....and I assume the case heads are all going to expand to the chamber limits and never exhibit case head growth....

Are there signs to look for that are specific to the single shot rifles?

.

Measure head diameter before fireforming. You can measure at the .200" line or just ahead of the extractor slot. Any increase in head diameter of more than .001" is an indicator you're at max or above.