Henry Rifle Forums

Don't know what the issue is it has with a MB 240 gr. coated cast bullet loaded over 9 gr. Unique? It was spitting them out high and left with a key hole from 40 yds. this morning Tried a windage adjust and lowered the rear sight as low as possible but they still stayed left.
Then I tried a load of same bullet but over 18.5 gr. of Alliant 2400 and bam there it was just to the right of center diamond and lower and no more key hole. Was aiming at the center of diamond as best as I could see but that red center diamond hard to see. Guess you have to run the bullet fast for the Henry rifle twist.

That key hole shot bothers me and will slug the barrel to see what it is which I can't remember if I did or not. This was a problem with the Marlin 44 Mag lever rifles too with a .430 bore

Aren’t most keyholes from a bullet to heavy for the twists? Just having one says it might have just been that bullet. How is the crown? I’ve damaged crowns before which can change the point of impact. It’s also something that can move around when you change speed or bullet weight.

Just guessing.

Sir Henry wrote: ↑

Wed Aug 04, 2021 6:01 pm

Aren’t most keyholes from a bullet to heavy for the twists? Just having one says it might have just been that bullet. How is the crown? I’ve damaged crowns before which can change the point of impact. It’s also something that can move around when you change speed or bullet weight.

Just guessing.

Only shot the coated MB bullets today and bore is nice and clean looking. The crown looks fine and yes key holing can be because of a too heavy bullet
not up to speed. However the Henry is supposed to shoot standard 240 gr bullets okay. Could be that it doesn't care for .44 Mag low or mid level loads?

I have checked the speed of both loads thru the Henry and the 240 gr MB bullet with 9.0 Unique travels at1300-1325 FPS. The 18.5 Alliant 2400 load with same bullet is going 1540 to 1570 FPS. Maybe that is the sweet spot for a 240 gr. load in the 16.5 inch Henry Carbine.

Also a bullet to small for bore size can cause key holing and erratic groups. Will slug the bore and compare to bullet size.

A while back I loaded a 300 gr.MB cast bullet in a .44 Special case with 11 gr. of 2400 powder to get the COL to 1.575 so it would cycle in the Henry.
Clocked at 1220 FPS I got a key hole hit on the target.

interesting .... MB puts out good bullets but its possible you got a bad one .... the fact that it is the only one you've had to tumble, my first reaction is a bad bullet ..... the only bullets I've ever loaded that keyholed were coated Acme 500 Grain RNFP fired from our 45-70 --- http://www.acmebullet.com/bullets-reloa ... uct_id=446 .... my belief is they were just too heavy for our rifle to stabilize .... I've fired bunches of brands of 240 gr'ers out of our 44 and none have keyholed

Yeah, that's mighty interesting on the whole target; especially that tumbler. Forty, just a thought, are these MB's fairly new? maybe manufactured during the covid backlog?

My last order for the 240 K bullets was July 2020. They are a different color from the last batch so I will measure a few of each. They should be .430

Hickok45 talks about key hole issues with his JM Marlin 94. Go to 3:05 of his video. https://youtu.be/Bc4xzZqQogg

Forty are those the MB Smashers?
Anyway I loaded those same loads using the Smashers and will give them a try in my BBB one afternoon and get back to ya.
Key holing can be a variety of things.

I never understood where the one in 38 twist for the .44 Magnum rifles came from. The revolvers in that caliber don't use it.

Forty you might have your answer without changing bullets. Your load with 2400 is going about 240-250 fps faster than the Unique. Before I worry about a different bullet I'd just run those bullets faster. Changing bullets (.432) for the Henry may create problems for any other 44's you have.

Paul