45-70 bullets tumbling

buckmaster270

buckmaster270

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Hello all:
I have a Pedersoli Sharps 1:181/2 twist.
500 grain bullet cast in a Lee mold then sized and lubed. loaded them up with 41gr Varget because that's what I had available. load from the Lyman manual. bullets are tumbling with poor accuracy. I have shot 405 grain semi jacketed soft point with 41 gr Varget with 1.5" groups at 80yds (taking into account my old eyes and open sights.
According to what I've read, this rifle should like a heavy bullet. Not sure where to go from here. I have been debating investing in a Creedmore tang sight but I'd like to sort this out first.

any and all advice much appreciated
thanks
 
Did you slug the bore to check for proper sizing diameter. Doesn't sound like that is the problem just a good place to start from. Twist rate sounds fine a 500gr round nose bullet.
Check to see if the bullets are stripping in the bore from being undersized.

RC
 
Don't have your book, but I note that the Hodgdon site doesn't list Varget for anything over 400 gr. Perhaps that's because nobody makes heavier ones (guess)?

Obvious question - have you miked the bullet?
 
I was shooting cast 500-512 grainers in my Sharps. Smokeless yielded horrible groups. Pyrodex caused the groups to tighten considerably. The bullets were sized to .458 by the caster and were 30:1(soft).
Smokeless shoots fine with jacketed bullets but not with the cast bullets I had.
I never experienced this when shooting cast from revolvers.
Here is a link to an article I found very helpful. It is not the gospel but helpful. http://www.wahsatchdesperadoes.com/Intro_to_BPCR_Loading.pdf
 
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Is your bullet alloy hardness compatible with your velocity and rate of twist? It sort of sounds like the bullet isn't getting spun, perhaps due to a badly fouled bore, which subsequently allows the bullet to push through the rifling. Ensure the bore isn't fouled, then try using the same bullet at a lower velocity, say 1200 rather than 1500 and see if the problem is corrected.
 
Gun is new and no problems with jacketed bullets so I didn't slug the bore. I miked the bullets and they are .457 same as the jacketed ones . I may try BP . according to Speer manual, 41gr of Varget yields 1337 so I could try a lighter load
 
Had the same problem with mine. Your rifle wont stabilize heavy bullets. The heaviest I could shoot out of my pedi was 420 gn. The 405 gn lee bullet will shoot better out of it. The 1-18 twist is too slow for thoses bullets...
 
try a faster powder , i use 10-12 grs of unique, or 60grs of black,, with that bullet in my shiloh for a practise load ,, i dont think your powder is hot enough to upset your bullet as blackpowder will ,make sure you use a card wad between the black and that bullet as you must protect the bullet base , i cut them from milk cartens,,,wade
 
cooner said:
Had the same problem with mine. Your rifle wont stabilize heavy bullets. The heaviest I could shoot out of my pedi was 420 gn. The 405 gn lee bullet will shoot better out of it. The 1-18 twist is too slow for thoses bullets...
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I have to agree with you. 500 grain cast bullets need to be at least .001 over bore diameter, .002-.003 is even better. Especially with hard cast bullets.

Lead bullets depend on upset (expansion) to properly grip the lands.

I have three different 45-70 chambered rifles. One is an 1883 Cadet Trapdoor that I only shoot cast bullets in that have just enough antimony added to reduce fouling. The bullets are not resized and throw at .461from my mould. My bore measures out at .459. I shoot both smokeless and BP in it. I has a standard issue twist rate of 1-15 and shoots a 505 grain Postill style bullet quite well.

The other two are on Siamese Mauser actions. One has a 1-18 twist rate and the other has a 1-15 twist rate. The 1-18 twist will shoot 405 grain and lighter cast bullets very well when they are sized at .459. It won't behave at all with heavier bullets, no matter what size they are cast to.

The second rifle has a 1-15 twist and will digest anything cast that is sized to .459 as well, right up to the 505 grain Postill and some 500 grain Woodleigh bullets I picked up at a gun show a few years ago. In the Siamese rifles, I cast hard so I can load to faster velocities.

The thing is, I am recoil shy because of a "frozen shoulder joint" and find the heavier bullets a real pain to shoot. The only reason I keep playing with them is the off chance that I might get a buffalo draw before the rest of my body gives out on me.
 
+1 on what cooner said. I spent over a hundred dollars on a nice bullet mold after starting with a Lee 405 plain base. My Marlin likes the Lee best - so far. I would try to get a mold that turns out something similar to the jacketed bullet your rifle likes.
 
1:18 twist is not at all too slow for 500gr bullets in the .45-70. I shoot well over a thousand rounds of .45-70 in 1-18 twist barrels every year. Not one of those bullets weighed less than 520gr and most have been heavier. None of them tumbled. If you don't believe me then do some research on the twist rates in the original Springfield rifle.

I expect that the bullets are undersized and that the alloy is too hard.

Chris.
 
Same diameter when comparing jacketed to lead cast has no real bearing on what works. Copper is so much tougher than lead that it makes a huge difference if the round is copper jacketed or not.

My Enfield slugs .315 but .3105 jacket bullets work fine in it. For cast bullets anything under .312 tumbles and leads the barrel something awful. I need to get down to .3085 jacketed rounds before I get tumbling.

My .44 mag Marlin eats up .429 jacketed rounds no problem but lead cast need to be at least .430 to not tumble and .432 to not lead the barrel horribly (damn micro groove rifling!)

My .45-70 H&R Handi Rifle is fine with .457 jacketed but much prefers cast to be .460 or so to get better accuracy.

These are just a few examples. The specific hardness of the lead will also change things up a tad but not as much as lead vs. copper.
 
gunlaker said:
1:18 twist is not at all too slow for 500gr bullets in the .45-70. I shoot well over a thousand rounds of .45-70 in 1-18 twist barrels every year. Not one of those bullets weighed less than 520gr and most have been heavier. None of them tumbled. If you don't believe me then do some research on the twist rates in the original Springfield rifle.

I expect that the bullets are undersized and that the alloy is too hard.

Chris.
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I believe that both Shiloh-Sharps, and C. Sharps both use 1-18 twist barrels as a standard in their guns. And these are the guns that everybody wants to buy for BPCR.
 
gunlaker said:
1:18 twist is not at all too slow for 500gr bullets in the .45-70. I shoot well over a thousand rounds of .45-70 in 1-18 twist barrels every year. Not one of those bullets weighed less than 520gr and most have been heavier. None of them tumbled. If you don't believe me then do some research on the twist rates in the original Springfield rifle.

I expect that the bullets are undersized and that the alloy is too hard.

Chris.
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I've tried several different mixes for hardness with the 1-18 twist barrel and no luck. I've also cast the bullets up to .004 over bore diameter as well as .001 increments lower.

You've definitely got my curiousity up now and I will have to try again.

Obviuously I'm doing something wrong.

Thanks for the info.
 
bearhunter said:
I've tried several different mixes for hardness with the 1-18 twist barrel and no luck. I've also cast the bullets up to .004 over bore diameter as well as .001 increments lower.

You've definitely got my curiousity up now and I will have to try again.

Obviuously I'm doing something wrong.

Thanks for the info.
Click to expand...

I must admit that is weird. What you are trying should have worked. 1:18 twist is pretty much the standard for any black powder .45 cal barrel these days although some are trying 1:16, and there are some 1:20's.

The only time I've had cast bullets tumble is when I tried Bullet Barn 450gr flat nose in my 1:20 twist Browning traditional hunter ( I'm pretty sure that was a bullet sizing issue.), and shooting 520gr Postell style bullets in a 1:20 Ruger #1. That Ruger had a tight spot in the barrel under the front sight and I think it just hated cast bullets.

I do have a pile of .45 cal single shots in 1:18 twist and they are all happy with heavy bullets. My bullets are all 1:20 lead/tin these days and I only shoot black powder. The exception to that is my lever guns which all use 405gr bullets and newfangled smokeless powder.

Chris.
 
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