Crayola of Death innaccuracy theory

[Dr.Phil]

Thanks for the info on the epoxy paint.
I applied about 4 coats and baked them @ 225F for 45 min.
After letting them sit for a week or so, I'm not too pleased with the result.
I'm able to scratch off the coating with my finger nail.
Oh well...
Back in the pot they go.
I need to get off my butt and order some powder.

Decided to do a little bit of plinking last night.
Shot 10 rounds of the GC COD loads and they still maintain reasonable accuracy.
At 100 yards, I was having no trouble ringing a six inch gong.
Other than my slower twist 1:8 Noveske barrel, I'm curious as to why they are shooting as well as they are.
After my next casting session, I'll load some more up and shoot them as soon as I can.
That way I can determine whether or not age hardening is a factor.

[yondering]

I'm building a 1:11 twist 30 HRT, and will try these bullets in that one. The slower twist might work, based on other reports on castboolits.

[Dr.Phil]

Time to start playing with the old COD again...

Since I had reasonable success with age hardened COD "Boolits" wearing gas checks, I decided to try it with gas checked pure Lynotype.
I've been meaning to get started with this "experiment" for several months now.
Yesterday, I finally got around to starting.
The weather was a nice 65 degrees & sunny, so I broke out the lead pot and got busy.

I anticipated spending no more than three hours casting.
8+ hours later, I got done cleaning up and ended up with about 600 COD projectiles.
Took me about an hour to figure out the temp of the melt to get them to cast properly with Lyno.
Ended up having to turn the pot "up to 11" to get the mold to fill properly.
When I was done, all of them came out looking perfect and shinny like a bag of silver.

Now, I have to seat gas checks, lube, size, and re-lube all of them.
Once that is done, I will do a full load development cycle.
Just received a new order of different powders and 5K of Small Rifle Primers.
That combined with my buddy letting me use his Lab Radar chronograph, should make things entertaining.
Hopefully this experiment won't be a huge waste of time any components...

I'll update this thread once I have some data to post.
The alloy that I used is super hard and there are little to no defects in the castings, so I'm expecting good things.
Has anyone heard of the COD in 300 BLK being tried with 100% Lyno?

[dellet]

Did that change the weight noticeably?

[Dr.Phil]

Haven't weighed them yet.
Will do so after I install the gas checks.

[yondering]

I'm building a 1:11 twist 30 HRT, and will try these bullets in that one. The slower twist might work, based on other reports on castboolits.

Forgot I had posted this.

It didn't work out; the COD gave shotgun patterns in this one at 10 yards, same as the 300 Blk. That was with water quenched bullets, powder coating, and copper gas checks.

I keep thinking they might work with about half the nose length clipped off, but haven't got back around to trying it.

[dellet]

I had a little different experience, but I went a different direction. I developed a subsonic load for an SBR. One of the theories was bent tips on loading. I had no problems. Speed might still be an issue, I never went there.

Here's a 50 yard target.


I wrote it up here.
viewtopic.php?f=185&t=97185

I will be very interested in what Dr. Phil comes up with.

[Dr.Phil]

The interesting thing about my new trial will be removing projectile bending / distortion from the equation.
The alloy that I used will result in a bullet breaking before it bends.
This should result in a projectile that performs like a jacketed bullet.
So, the test results should directly reflect how effective the projectile design is and remove most cast lead specific issues.

Ironically, with the alloy that I'm using, I'll have to keep the velocities fairly high.
Minimum pressure is going to be 31,000 psi in order for the bullet to properly obturate.
So, subsonic testing like dellet did will be off the table.
(Dellet is still welcome to a care package with some samples if he wants to do some supersonic testing though...)

FWIW, my previous testing and positive results were with my old Noveske barrel that had a 1:8 twist.
The replacement barrel has a 1:7 twist, so that may be the difference between success and a complete waste of time.
Worst case, I'll load up any projectiles that I don't use in 300 BLK and make up some 308 Win loads.

[dellet]

The interesting thing about my new trial will be removing projectile bending / distortion from the equation.
The alloy that I used will result in a bullet breaking before it bends.
This should result in a projectile that performs like a jacketed bullet.
So, the test results should directly reflect how effective the projectile design is and remove most cast lead specific issues.

Ironically, with the alloy that I'm using, I'll have to keep the velocities fairly high.
Minimum pressure is going to be 31,000 psi in order for the bullet to properly obturate.
So, subsonic testing like dellet did will be off the table.
(Dellet is still welcome to a care package with some samples if he wants to do some supersonic testing though...)

FWIW, my previous testing and positive results were with my old Noveske barrel that had a 1:8 twist.
The replacement barrel has a 1:7 twist, so that may be the difference between success and a complete waste of time.
Worst case, I'll load up any projectiles that I don't use in 300 BLK and make up some 308 Win loads.

Do have to ask if I want the chance to push something until breaks?

I still have some of the lead ones you sent, it would be fun to compare the two. I'm pretty sure sure I can get them spinning any where from 100-300K.

[yondering]

I'm building a 1:11 twist 30 HRT, and will try these bullets in that one. The slower twist might work, based on other reports on castboolits.

Forgot I had posted this.

It didn't work out; the COD gave shotgun patterns in this one at 10 yards, same as the 300 Blk. That was with water quenched bullets, powder coating, and copper gas checks.

I keep thinking they might work with about half the nose length clipped off, but haven't got back around to trying it.

SUCCESS!!
Apparently, that thin unsupported tip really is the problem; getting rid of that fixed the bullet for me.

Since this thread reminded me, I tried shortening the noses on these. I had a handful already coated and checked, so I stuck them in the lathe and cut off part of the nose. I tried shortening the noses to .125", .150", and .175" meplats (lock the calipers at the desired meplat size and spin the bullet nose between the jaws to mark it); all of these gave much better accuracy. The same bullets before clipping gave shotgun patterns at 10 yards from my 9" 1:8 AR pistol, with most of the bullets impacting sideways; after clipping off the noses they all shot great. I was not able to do any accuracy testing beyond 25 yards today, but the results are far better than anything else I've done with this bullet. These were full power supers, not a subsonic load.

I no longer have this mold, but if I did, I'd fill part of the noses with a spacer to make them cast as a flat nose. As an alternative, a guy could make a simple fixture from a block of steel with a hole in it, sort of like a case trim die, to trim the noses all the same length.