Bump Die

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  • Last Post 18 December 2021
Wm Cook posted this 14 December 2021

The number of outstanding threads that are in the archives is outstanding. Can anyone tell me if this developed into a full article in the FS?

https://forum.castbulletassoc.org/thread/making-a-bump-die/?order=all#comment-783f0652-a310-4207-bd52-a71a01726d1d

A “Measured Response” is as effective as tongue lashing a stuck door.

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OU812 posted this 15 December 2021

It was never in FS.

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Wm Cook posted this 15 December 2021

Shame. It’s a great design. Congratulations on doing what you did though. I have a small Jet lathe but I’m machine shop challenged and need more detail. Good job though. Bill.

A “Measured Response” is as effective as tongue lashing a stuck door.

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OU812 posted this 15 December 2021

My next experiment will be bumping powder coated bullets. I have an undersize 30 cal bore riding mould that will work perfectly. Simply fill lube grooves before squeezing or bumping more round.

Imagination is better...

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John Alexander posted this 15 December 2021

OU812 says:

"it was never in FS."

That is a shame.  I have just reread the thread and I think it contains 90% of the material for a super Fouling Shot article just waiting to be put together.  A two to three part article made from your posts would be a major contribution to the CBA and to cast bullet shooters in general.

Please consider putting it together and submitting to Glenn. It should be in the cast bullet literature not hidden in our archives.

John

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Wm Cook posted this 16 December 2021

It would be a mold savior for sure. My 311299 drops right at .300 and my bore is ~ .3014.

With a controlled bump die it would also give you all of the necessary components to compare a .300 vs .301 vs .3015 nose in a very synch controlled experiment. I’d love to have a chance to pull that off.

I finished my .300 vs a beagled .3012 ~ .3018 nose and MOA improved statistically. I don’t have the numbers in hand but the average of 4 five shot group’s shrank from 2.5?? To 1.7??.

Enough that I convinced myself about bullet tipping and that there is a sweet spot effected by alloy and the diameter of the nose.

A “Measured Response” is as effective as tongue lashing a stuck door.

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OU812 posted this 17 December 2021

The hard part is making a top punch for the Lyman 311299 bullet. Bullet must be squeezed in die to make fatter. The nose of bullet would be deformed if top punch does not conform close to perfect.

Have you tried powder coating to make larger?

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OU812 posted this 17 December 2021

Have you noticed the flat/tapered tip bullet shape of Accurate moulds. It is much easier to make top punch for this style bullet.

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John Carlson posted this 18 December 2021

I have used a flat nose top punch (NOE 311188FN) when bumping 311299 bullets (no bump die, just using pressure).  It re-shapes the nose but they come out very uniform and shot at least as well as those that I bumped with the Lyman top punch

John Carlson. CBA Director of Military Competition.

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