PC gives me 30% keyhole while shooting

[popper]

Cull boolits not completely filled out, yes, if they just slip through mike them. Check for complete coating in drive bands. 50/50 COWW should be good, SOWW may be too soft. No sense in tossing nickels down range without hitting the target.

[StromBusa]

QC Quality Control
QC&I Quality Control & Inspection.

Some need to return to the melt

[philproulx]

Have you slugged the barrel to confirm diameter and secondly I would try hardening up your alloy.


it's wheel weight , so i can put more TIN in the mix?

[popper]

Tin won't harden much.

[Maximumbob54]

If you are using HF powder at 400 degrees then dump them from the tray into the water again. That might help.

[philproulx]

i just found my problem
i change my regular setup on my dillon
took out the lee FCD and put a regular Seater
shot 50 rounds tonight at 10 yards they where all touching
shot by my glock 35 regular barrel

thanks for all the help

[Walter Laich]

Glad you found the problem. sometimes they never seem to get solved

[dilly]

Glad you posted resolution. That makes this site more valuable for the thousands of unspoken trouble shooters that travel far and wide to solve their roaming woes.

[hickfu]

Its ALWAYS the FCD!!!

[tiger762]

So do I understand correctly that the Lee FCD is actually reducing the diameter of the bullet? I always thought that by whatever amount it got reduced, that it sprung back.

[philproulx]

yea it's reducing the bullet diameter

[bosco555]

'Keyholeing' is a result of loss of stability. But just why is this loading loosing stability?

Bad barrel, leading of the barrel, improper twist for the load, rifling too shallow for the bullet at the velocity?
To the bullet/s. Improper fit, too long for the twist, to slow for the twist, too hard/soft to take the rotational motion from the rifling.

I'm going to by-pass the barrel being at fault for the time being. And look only at the bullet combination. Roughly 30% failure rate at the tested range.

Start by eliminating the 'flaking' of the coating. Check the cure time and make certain that the bullet surfaces are very clean and dry (no oils or grease).
Increase the velocity a little and re-test.
Check the bullet to bore fit (slug your barrel and compare, 1 to 3 thousands larger bullet to bore).

If the bullet fit is right and pushing a little faster doesn't reduce the failure rate, options are getting slim.

Here is a formula that may help determine the instability problem.

Just copy this and paste it into a spread sheet (block C1 is a good option).

=(30*+C5)/((+C7/+C4)^2*+C4^3*+C6/+C4*(1+(+C6/+C4)^2))*(+C8/2800)^(1/3)*((+C9+460)/(59+460)*29.92/+C10)

Then copy and paste this (to make it simple, put the 'Where' in block E2).

Where:
Sg - is the stability coefficient and should not be less than 1.4, but more is ok
C4 - Caliber in inches (.223 for both .222 and .223)
C5 - Bullet Weight in grains
C6 - Bullet Length in inches
C7 - Barrel Twist in inches per turn
C8 - Muzzle Velocity in fps
C9 - Temperature in degrees F (59F normally used)
C10 - Pressure in inches of mercury (29.92 normally used)

This will put the variables in the 'C' column from row 4 to 10. The numbers will have to be typed in to the 'C' column. The location that you put the formula will display the final calculation value.

It is not that hard.

I hope this helps a little.

OSOK

Osok...The above formula returns an error #DIV/0!...sorry to be a pain!!

[bosco555]

Also...What do we do with the number from the equation? What does that represent? Thanks again
bosco

[oldpapps]

bosco,

I'll try to answer your questions first.

" What do we do with the number from the equation? What does that represent? "
The 'number' is only a point on a scale and means nothing in it's self. It is the stability coefficient and should not be less than 1.4.

Now to the spread sheet.

DIV/0 - divide by the number of '0' is an invalid mathematical operation. One of the variables is missing or invalid.
If each of the variables is/are entered in 'cells C4 to C10', all should be well.
The actual location of the formula is the location the numeric value will be displayed. As the variables are in the formula source locations, each cell must have a numeric value for the formula to function. Check that the variables are entered in 'cells C4 to C10'.

I don't know if I have helped. I hope I have.

OSOK


P.S.
When I looked at the times of your posts, I thought you were just up at night. Your locations is listed as 'In The Wild West of OZ'. To me 'OZ' is Kansas, as in 'The Wizard of OZ' movie. Then I see you are dealing with 230 volt conversions in Australia. Guess you weren't up all night.

Enjoy,

OSOK

[Sitzme]

For those without Excel experience, you may have to uncheck the "r1c1" option under "file->options" before pasting in the formula.

[bosco555]

bosco,

I'll try to answer your questions first.

" What do we do with the number from the equation? What does that represent? "
The 'number' is only a point on a scale and means nothing in it's self. It is the stability coefficient and should not be less than 1.4.

Now to the spread sheet.

DIV/0 - divide by the number of '0' is an invalid mathematical operation. One of the variables is missing or invalid.
If each of the variables is/are entered in 'cells C4 to C10', all should be well.
The actual location of the formula is the location the numeric value will be displayed. As the variables are in the formula source locations, each cell must have a numeric value for the formula to function. Check that the variables are entered in 'cells C4 to C10'.

I don't know if I have helped. I hope I have.

OSOK


P.S.
When I looked at the times of your posts, I thought you were just up at night. Your locations is listed as 'In The Wild West of OZ'. To me 'OZ' is Kansas, as in 'The Wizard of OZ' movie. Then I see you are dealing with 230 volt conversions in Australia. Guess you weren't up all night.

Enjoy,

OSOK

Hahahaha...yeah I'm from "Down Under", thanks for the clarification and sorry about the div/0 I got it sorted...I'm having a root canal treatment at the moment and in pain so my brain doesn't function too well...And these days..sleeping is an option...lol...

I entered the values for my 458WinMag rifle as I was experiencing bad key-holing, but I got a 7.59. However I have managed to get to the bottom of the problem.

The issue is too little contact between the boolit and the rifling. I have tried other cast boolits with less grease grooves and the key-holing went away altogether. This is with the same amount of powder, same crimping and gas checks installed. For those interested I use 66gr of Re10x and 420gr GC boolits..giving a MV of 2200fps.

I have ordered a mold with just one groove (for crimping) and also some hi-tek coating to see if I can get these boolits good to go.

I shoot big game competitions and rules dictate a min of 2200fps muzzle velocity, which I can achieve and accuracy is really good, I will post dome pics as soon as my tooth decides to co-operate. As you know, the 458 is like a grouchy, bad@$$ mule when shot from a bench-rest position, but I will do that and post the pics...
Thanks again
bosco

[Maximumbob54]

It's only the LFCD when you use one without knowing how it works.

[philproulx]

I got all under control now
10 shot group at 10 yards
My load is good it makes major in IPSC
Shot out of my Training glock 35 with stock barrel
the other pics shows my barrel after a 1000 rounds , i wiped that in one stroke of a patch, it was gunpowder carbon no lead or coating

since we are short of powder up here in canada , i had to load with Bulleye and Unique , 2 powder that i have not work with previously
5.3 gr of bulleye @ 1.130
5.5 unique same oal

[Del-Ray]

The LEE factory crimp pistol dies can be used for cast bullets, but I find they work better if you break the carbide ring out of the bottom of them. Then they work just like the rifle versions. They crimp only, and no longer do an extra resizing to the cartridge.