Crayola of death revisited

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dellet
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Crayola of death revisited

Post by dellet »

I got a wild hair and wanted a light subsonic load for my SBR. Not exactly sure why, but trying to do something with the "Crayola of Death" just sounded like fun. Since I don't cast, I put the word out, Rebel and DR. Phil donated some to my cause, Thanks guys. One word of warning they both gave me was a polite way of saying I was a fool, but to let them know how it worked out.

I did another write up of how I developed the load here:
viewtopic.php?f=141&t=96500&start=30

I had heard this bullet was hard to work with, and I hope that I might have stumbled on a few things that might help others work up a good load.

Rifle is:
7" Excaliber barrel, 1/6 twist .098 port
JP silent captured black spring, steel weights
LMTe F/A BCG
Gemtech GMT300 suppressor.

The load is;
11.1 grs 4227
1.355" converted LC brass
CCI#41 primer
2.100 COL
1000 fps avg

I used two different castings. The first were actually cast by Dolomite, he gave some to Rebel, who passed some on to me. They are powder coated wheel weight lead and sized to .310. There some of both gassed checked versions and non. The gas check versions, were ran without and they proved troublesome. I never had two good groups. The group below was pretty average once I got the load down for the non gas checked versions.

Image



This was better than average for the gas checked version. Sized .310 and powder coated
Image

This was the best group of the gas checked, powder coated, sized .310 from wheel weights
Image

Dr. Phil sent me some that he tried a new secret coating that should remain a secret. The coating held up to sizing but was brittle and if it did stay on when seating, I am sure that it did not last in the barrel. I sized these to .311
Image



Second group of bullets, these are the same as the painted bullets with the paint removed, (I scraped it off with my thumbnail) sized to .311 and lubed.
Image

I have a significant first round pop in the suppressor along with an increase in velocity. I hope when I get a chance to try a different suppressor that the first shot settles in. The bore is only cooled a couple minutes, enought time to change targets and reload the mag. The shift is predictable and reasonably repeatable, always high right.

Remember these were two different batches, cast by two different people, so that seems to show some consistency. The Load appears to be reasonably the same for accuracy across the two different batches.

Sizing to bore made a big difference, the bullets that lost their coating proved that.
The 2.10 length was a compromise. It put the edge of the brass midway on the top bearing surface. When I went longer it seemed that there was not enough bearing surface in the neck to keep the bullet straight, shorter accuracy fell off.
Coating and the ability to keep it on the bullet turned out to be important.

Next is to work up the velocity and see where accuracy falls apart. I know one of the theories about this bullet was that the nose was bending. I think that it fed well and shoots pretty good for that to be the case for me. I know that these were cast a long time ago and am to understand that they get harder with time. So that may be what saved me.

This was my first trip down the cast bullet rabbit hole and it was enjoyable. As for a justifiable use for the load and bullet, shooting 2" spinners in the front yard at 50 yards was entertaining.
300 Blackout, not just for sub-sonics.
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rebel
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Re: Crayola of death revisited

Post by rebel »

I think I said " you damn nutjob " not fool :mrgreen: Still, the load cycled and I somehow knew you would get this worked out. Thank God for folks that try different things. Sharing this experience has made me take a new look at how my rifles cycle and how to fine tune them.
You can't beat the mountain, pilgrim. Mountains got its own way.
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Dr.Phil
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Re: Crayola of death revisited

Post by Dr.Phil »

Very cool!!!

Sorry about the bullet coating.
That alternate to PC listed on Cast Boolits Forum is definitly a NO GO.
http://castboolits.gunloads.com/showthr ... -out/page2

Next batch will be linotype.
(I'll be sure to set some aside for you.)
Since age hardening seemed to work well for my last batch of CODs, the linotype alloy should perform comparably.

Keep up the good work!
"Don't tell fish stories where the people know you; but particularly,
don't tell them where they know the fish."
--Mark Twain
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dellet
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Re: Crayola of death revisited

Post by dellet »

Dr.Phil wrote:Very cool!!!

Sorry about the bullet coating.
That alternate to PC listed on Cast Boolits Forum is definitly a NO GO.
http://castboolits.gunloads.com/showthr ... -out/page2

Next batch will be linotype.
(I'll be sure to set some aside for you.)
Since age hardening seemed to work well for my last batch of CODs, the linotype alloy should perform comparably.

Keep up the good work!
I look forward to more testing.

I am confused about the first round always being about 40fps+, with the coated bullets even in a barrel that has had 20 rounds or better through it. The tumble lubed bullets gained 90fps first shot. Being so repeatable makes me feel it is rifle or suppressor (what actually happens with a first round pop?) more than load.

I was happy everything was repeatable.
300 Blackout, not just for sub-sonics.
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