266 grain cast bullet, the Dolomite special

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ShootNstuff
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Re: 266 grain cast bullet, the Dolomite special

Post by ShootNstuff » Mon Aug 15, 2022 4:00 pm

But in my case we are only at 1022fps and you can see on the poster board so signs of shredding. A slight wobble with one shot and the second shot clean hole, no wobble.

Would slowing it down to 950fps make a difference?

Have you shot these bullets through a 1/5 before?

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dellet
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Re: 266 grain cast bullet, the Dolomite special

Post by dellet » Mon Aug 15, 2022 4:55 pm

ShootNstuff wrote:
Mon Aug 15, 2022 4:00 pm
But in my case we are only at 1022fps and you can see on the poster board so signs of shredding. A slight wobble with one shot and the second shot clean hole, no wobble.

Would slowing it down to 950fps make a difference?

Have you shot these bullets through a 1/5 before?
Most of the basic testing is on the first 5 pages. Shot it in everything from a 1/5-1/10. 5 and 10 is where it starts to fall apart.

Early testing at 50 yards showed the 1/10 to be the most accurate, it went to crap at 75 yards. The 1/5 made it to 100.

A 1/5 twist takes more work for load development, it puts a lot of stress on all bullets. I’ve blown up 110 varmageddons, had Lehigh 194’s open up in the barrel, Lapua 100’s come apart in flight. Doesn’t matter, sub or super, most bullets aren’t made to handle high pressure, fast starts into tight twists. Slower powders help, but it’s always bullet dependent and once the barrel heats up. All bets are off.
300 Blackout, not just for sub-sonics.

ShootNstuff
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Re: 266 grain cast bullet, the Dolomite special

Post by ShootNstuff » Tue Aug 16, 2022 12:15 am

Image

Smash test on my dummy round and acetone test… click on the image to blow it up.

This is my first experience with coated lead bullets, but this can’t be right.

Definitely not “molecularly bonded”. You can see the flakes on the pad and counter. My thumbnail can take it off. There is no way this coating would stay on during feeding in an AR.
Last edited by ShootNstuff on Tue Aug 16, 2022 12:18 am, edited 1 time in total.

ShootNstuff
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Re: 266 grain cast bullet, the Dolomite special

Post by ShootNstuff » Tue Aug 16, 2022 12:17 am

I am using the .312-308 NOE expander, I think I gave the wrong size in my first post.

ShootNstuff
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Re: 266 grain cast bullet, the Dolomite special

Post by ShootNstuff » Sun Aug 21, 2022 2:23 pm

Nothing regarding the coating? Seems pretty bad to me.

2manyToys
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Re: 266 grain cast bullet, the Dolomite special

Post by 2manyToys » Sun Aug 21, 2022 3:04 pm

ShootNstuff wrote:
Sun Aug 21, 2022 2:23 pm
Nothing regarding the coating? Seems pretty bad to me.
Yes, that's bad. While I haven't applied HTC, I have done lots of powder coat. What you are seeing would be considered failed coating adhesion in my book.

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GunFunZS
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Re: 266 grain cast bullet, the Dolomite special

Post by GunFunZS » Fri Sep 09, 2022 12:21 am

dellet wrote:
Mon Aug 15, 2022 3:22 pm
My instructions were “see if you can make this bullet and coating fail”

Image

viewtopic.php?f=128&t=102326&p=985663&h ... ed#p985663

Too much pressure, too soon causing too much acceleration. It’s easier to compress the bullet and push it over the lands, than to spin it. Note the 1900 fps. Bullet, the engraving starts straight.

There is a reason a lot of cast shooters use a gain twist barrel if they want a fast twist like a 8 or 9.
Thanks for doing that again. I need to get some more alloy so that I can send you the new version!

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