bullet length

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  • Last Post 20 June 2020
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Ross Smith posted this 17 June 2020

I have a muzzleloading benchrest rifle. All 50 lbs of it. The slug is a 2 part bullet. The base is pure lead and the nose section is 20:1 lead tin. The soft base is for ease of loading and to obturate into the grooves. The 20:1 nose is meant to with stand the guff of loading from the muzzle. The two halves are swaged together. Relax, I cast the individual halves. It is also paper patched. My question is: Is there a relation(formula) between the tapered nose section and the straight base? In other words how much straight bore/groove riding part compared to the tapered nose that doesn't engage the rifling? clear as mud? The reason I ask is both molds are adjustable for length.

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45 2.1 posted this 17 June 2020

You should have a minimum 60% bearing length..... to not over 75% on normal smokeless cast bullets. Both pure and the 20:1alloy will bump easily with black powder dependent on the loading. You can get away with more with what you're trying to do. It depends on what the nose profile looks like, your load and the weight range you want.

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Ross Smith posted this 17 June 2020

That helps.

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Ross Smith posted this 17 June 2020

These bullets that I currently have are1.594 long, nose sectionabout .919, base is .68. After beating one thru the false muzzle assembly I get .774" of rifled length or just about a 50/50 ratio. Of course that changes as soon as the powder goes off. Maybe try a little longer base? The bullet already weighs 772 grains. The shorter one piece bullets I tried did not work very well.

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porthos posted this 17 June 2020

Ross:  how does something like this shoot  (5 or 10 shot groups)??

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Ross Smith posted this 17 June 2020

I've had varying results. The rifle and the molds and swages have all needed some maintenance and repair. So I'v never had any consistency. Hopefully everything is usable now and I can concentrate on what works. I've shot .75" center to center 5 shot groups but that is not typical. The rifle held the NMLRA record of 50-5x for the 100yd benchrest in 1955. This is documented, I think. Always need my caveat.

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Bud Hyett posted this 17 June 2020

Were I ever to get into muzzle-loading, this style would be my venture. I knew a man in Illinois who shot this match, he tried to hook me into this style and he almost succeeded. He passed away in 2000, I still think of him with memories of our black powder adventures. 

I recall that everything was fastidious; load, bullet alloy, brand and lot number of percussion cap, outside temperature in 10 degree increments, humidity, etc. He kept an indexed notebook that went with him to each match. He hoarded a match-only supply of Curtis and Harvey powder he bought at a sale for little money.

I wish I could help more, but I think you will need to experiment with loads and keep extensive records. The good side of this is you must spend more time at the range. Any excuse for shooting will do. 

Farm boy from Illinois, living in the magical Pacific Northwest

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Ross Smith posted this 18 June 2020

You nailed it Bud.

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358156hp posted this 20 June 2020

Check out Idaho Lewis on youtube whe you get a moment. The guys simply amazing, and amazingly simple. I damn near went out and bought a muzzle loader after a few PM exchanges on another board.

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