POI shift with BP

I inherited a Colt SAA 44-40 many years ago when my dad passed in 1972. It’s an early smokeless frame and I have shot it a great deal, primarily with smokeless - it generally shoots to point of aim at 20 yards with most loads. Just for fun, I loaded some full charge BP rounds using the Accurate Mold 43-215C boolit at 40/1 lead tin, sized to .429, over 37 grs Goex FFFg and compressed about .375 deep. Lube was standard SPG.

Those loads grouped pretty well into about 3” but about 8” to the left - this was offhand with no rest. I recovered several slugs and it looks to me like they skidded on the rifling, which I assume would normally open groups but not throw them that far off centerline. I’m considering going to a 20/1 alloy to hopefully raise hardness a bit and hopefully still allow some expansion. Any thoughts would be appreciated.

Thanks, HW

BP makes a lot more recoil in 45 Colt than smokeless does. My own SAA does the same thing except displaced vertically. The windage thing probably is your hold. I've learned that you can sight it for BP or for smokeless but not both without adjustable sights.

HWooldridge, think you have a typo on your bullet size. For what it’s worth, original 44-40’s were pure lead

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Originally Posted by Castaway

HWooldridge, think you have a typo on your bullet size. For what it’s worth, original 44-40’s were pure lead

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You are right about the size - I fixed it.

40/1 is pretty soft and casts easier than pure due to the tin - although I could give it a try. Just think it’s weird they all grouped same as smokeless on elevation but 8” left.

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Originally Posted by Nobade

BP makes a lot more recoil in 45 Colt than smokeless does. My own SAA does the same thing except displaced vertically. The windage thing probably is your hold. I've learned that you can sight it for BP or for smokeless but not both without adjustable sights.

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yes ----this!

Before I wasted my too few brain cells, I’d sand bag it just to confirm the shift wasn’t due to either torque during recoil or overcompensation on my part in anticipation to recoil. Keep us updated

HW that load with that bullet in my Miroku 1873 shoot less than 2” @100 yds. with 16:1 alloy. Recoil is there as well not a lot in a rifle but would be more felt recoil in a handgun.

I certainly could benchrest it - but I'm accustomed to shooting 44 mag factory loads in a Ruger so I tend to doubt it's a flinch. I'm going to drop to a slightly harder alloy and will report back results. The bore on this old girl is not great and she tends to like harder cast or jacketed pills - and the apparent skidding on the recovered slugs is bothering me. I may fire some into a 55 gal barrel of water to see what happens.

You haven't said any thing about the size of your chamber throats, nor the groove diameter of the barrel. Size you bullets to just over the chambers. That might help with the "skidding" you are seeing. And in my experience shooting BP cartridge guns (since about 1985) softer bullets generally work better than harder. I would think your 40-1 alloy should shoot just fine in that original revolver.

YMMV,
Dave

The cylinder chambers will just pass a .427 gage pin and the barrel slugs .4275 but as I mentioned previously, the bore is rough. The bullets were sized .429 so they got a little squeeze going through.

I owned a 32-20 Marlin about 40 years ago which had well defined rifling but the bore was very pitted. At that time, you could only buy two factory loads off the shelf from any manufacturer; one was a soft lead bullet and the other was a JSP. I never handloaded for that rifle but discovered it would never shoot the lead version worth a darn - more patterns than groups, but the jacketed pills would all go into a 50 cent piece at 40 yards. Great rabbit gun for East Texas piney woods.

I'm going to shoot some known smokeless through it and see how those group - might even try some jacketed as a test.

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Originally Posted by HWooldridge

I inherited a Colt SAA 44-40 many years ago when my dad passed in 1972. It’s an early smokeless frame and I have shot it a great deal, primarily with smokeless - it generally shoots to point of aim at 20 yards with most loads. Just for fun, I loaded some full charge BP rounds using the Accurate Mold 43-215C boolit at 40/1 lead tin, sized to .429, over 37 grs Goex FFFg and compressed about .375 deep. Lube was standard SPG.

Those loads grouped pretty well into about 3” but about 8” to the left - this was offhand with no rest. I recovered several slugs and it looks to me like they skidded on the rifling, which I assume would normally open groups but not throw them that far off centerline. I’m considering going to a 20/1 alloy to hopefully raise hardness a bit and hopefully still allow some expansion. Any thoughts would be appreciated.

Thanks, HW

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You shot a decent group but its offcentre ?
didnt really lose accuracy but the point of impact changed?
this is mostly about where the gun prints that particular load !
I think looking at boolit hardness is entirely the wrong rabbit hole to go down .
have another go and hold off 8" to the right

I had an ASM 44/40 one time and a full charge blackpowder load would get most fellers attention at the club where I shoot - absolutely different than a working smokeless load.

I’m thinking 37 gr of 3 fg in a modern solid head cartridge case would easily qualify as a full load or a slight over load. Your not using old balloon head cases, a modern case with its reduced internal volume will reach max pressure with less powder. Are you using a slightly hollow base bullet that would keep the bullet base flared out tight to the rifling grooves?
Your shooting a max power load which is making max MV so bullet skidding on the rifling could be occurring. The conditions are ripe for it.
You could just try reducing your powder charge thereby reducing the MV and see if the fired bullets still show signs of skidding.
That experiment might confirm whether or not you need to cast harder bullets.

Did you figure out what was happening?

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Originally Posted by Nobade

Did you figure out what was happening?

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Not yet - been too cold here to go mess around with it. Maybe next week if it warms up a bit.

Doubtful the bullet was skidding in the rifling, if it was the grooves are probably full of lead. Plus skidding in the rifling would likely give you full bullet profile holes in the target.
Going to 20-1 won't hurt any thing, but it likely won't change the POI either.

Cold? in Texas?

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Originally Posted by RichardB

Cold? in Texas?

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We had an ice storm Thursday that shut down the northern half of the state. The moisture is mostly gone but the lows are still in the 20's at night. Our normal low temps are mid-forties this time of year.