Data for 500gr 45-70?

[Andy]

What 500gr cast bullet? Different bullets, different recipe's. .457 or .458 or larger? Pure lead or slightly hardened? Have you checked the powder manufacture website.
Fun shooting, scroll down to 45/70, 500gr. http://www.gmdr.com/lever/lowveldata.htm
Stevespages.com H-4198 From 25.0 grains to 41.0 grains for a 500 grain bullet. Start low, watch for pressure signs.

If you're referring to "pressure signs" on the brass, the problem with that old maxim is that pressure signs are notoriously deceptive in any event, and will only show up on brass at pressures well above what most rifles chambered for 45-70 can safely stand. A worse case example of this is when someone with an old pistol designed for 15K psi thinks that they can depend on the brass to tell them the pressure is too high - however, the first "pressure sign" they'll encounter is a damaged gun.

If the "pressure signs" are MV's, then you're much better off.

 

[saskgunowner101]

Be aware that the 45-70 x 500 gr bullet x IMR4198 data here shows at least 7gr higher than max in my reloading manuals. Don't know if it's a typo or what

I found a few loads that raised my eyebrows while having a look at the stevespages link.

IMR-4227 405 grain loads 5 grains above load data in my book.

Unique, showing 11 grains to 32 grains range under a 405 grain bullet...I sure wouldn't want to be the guy who starts walking up these loads. 17.5 grains is the highest I've seen printed in a book. I don't think 18 grains is going to grenade a strong rifle, but pressures would be rising quicker than gas prices in BC.

 

[Slamfire]

Best to heed the recommendations in the loading manuals. Based on maximum allowable pressure figures. For example 45-70 Marlin loads are held to 28,000 cup maximum, and Springfield loads are held to 17,000 cup maximum in the Lyman Cast Bullet Handbook.

 

[jethunter]

If you're referring to "pressure signs" on the brass, the problem with that old maxim is that pressure signs are notoriously deceptive in any event, and will only show up on brass at pressures well above what most rifles chambered for 45-70 can safely stand. A worse case example of this is when someone with an old pistol designed for 15K psi thinks that they can depend on the brass to tell them the pressure is too high - however, the first "pressure sign" they'll encounter is a damaged gun.

If the "pressure signs" are MV's, then you're much better off.

Yes. Pressure signs in 45-70 brass would indicate about 2-3 times the pressure the lever guns are meant for, and about 4-5 times the pressure a trapdoor springfield is good for.

Unless there is also something else going on, the action will probably detonate before the brass shows "pressure signs".

 

[jethunter]

What 500gr cast bullet? Different bullets, different recipe's. .457 or .458 or larger? Pure lead or slightly hardened? Have you checked the powder manufacture website.
Fun shooting, scroll down to 45/70, 500gr. http://www.gmdr.com/lever/lowveldata.htm
Stevespages.com H-4198 From 25.0 grains to 41.0 grains for a 500 grain bullet. Start low, watch for pressure signs.

ACTUALLY a lot of that is wrong.

I pretty well interchange data between jacketed and lead bullets in the 45-70 - because velocity isn't any different to speak of in bullets over 350 gr.

And DO NOT work up a 45-70 load until you see pressure signs - because the lever guns maximum pressure is well below where you start to see pressure signs in brass. That's really bad and probably dangerous advice to give on a forum.

And be aware that there are maybe some typos in the Steves Pages load data, especially for 45-70 using 500 gr bullets. Some loads are almost 20% higher than the listed max in other published load data.

 

[Slamfire]

Not a recommendation but the Hornady 500gr at 1500 fps MV in my Marlin GBL is fun and should perform well. Reasonable accuracy at 100 meters. The 1:20 twist seems to adequately stabilize this particular bullet. The Berger twist rate calculator indicates comfy stability.

Downside is the bullet needs to be seated to way above the cannelure in order to cycle. Possible reliability issue without a heavy crimp on a cannelure to keep the bullets in the rounds in place in the tube magazine under recoil. Not totally confident using the Lee Factory Crimp Die is enough.

http://www.bergerbullets.com/twist-rate-calculator/