Lets talk about the "flier", we are not talking about off the target or out
in the white. Its the "8" you get from what you called a good shot.
A typical machine rest group from the .32 shot 22-25mm group with 1 or 2
in 100 being 40-50mm outside the group. (25yds)
The same group in .38 shot 18-22mm with no shot out of the group.
The flier was found to be caused by varing case release neck tension
caused by the thinner wall of the 32 SW long case.
This problem does not occur with the thicker .38 or TOZ cases.
To eliminate the problem you can the thickest brand wall cases and
1/ Use new cases only. (Major comps I only use new cases.)
2/ Neck anneal the cases each reload
To reduce the problem
1/ Heavy roll crimp in a crimp groove (usually on a revolver load)
2/ Heavy parabolic on a Auto load (part roll, part taper)
Using thick walled cases causes its own problems with bullet diameters,
chamber sizes and available die sizes, but competition reloading needs
to be a full package. You need to load to suit your own pistol.
David Levene wrote:
As I said before, once I stopped using a taper crimp flyers became history. Thankfully I discovered that early in my reloading career.
Batched Geco brass
.312/.313 Lapua or Geco HBWC bullets (.308 barrel)
1.4grains Norma R1
CCI small pistol primers
Reasonably heavy roll crimp
Hi David
Your load should have been OK, with a .308 barrel and .312 bullet may be a little too big
but no problem with standard dies. After sizing and crimping I would guess the projectile
if you pulled and measured it would be around .311. With a heavy crimp you will get good
clean burning of the R1.
Where most of the problems are is a .313 barrel, .314 bullet, factory dies (.311-.312)
and little or no crimp.
Reloading reduces the bullet diameter to less than barrel diameter causing fliers and leading.
cheers
Merry Xmas
I'm looking forward to my next shoot with the MG4.
Just handloaded a new batch using the Lee Factory Crimp die after waiting two months for it.
I didn't resize the case, the crimp is beautifully formed and the case is perfectly round.
Hi David M,
How tightly do you believe the case should hold the projectile? I get that the case shouldn't be so small that it reduces the bullet diameter.
Should the bullet be a heavy press fit into the case - or is thumb pressure sufficient? Heavy thumb pressure or light thumb pressure?
I've just reloaded about forty rounds without sizing the case to maintain the bullet diameter (once-fired geco brass, 1.45gr V310 and 100gr Speer HBWC), and crimped a heavy roll with my new lee factory crimp die. The bullet (ø0.314") only needed a very light thumb push and the roll crimp pushed it slightly deeper as it rolled over the top. My view is that the case should grip the bullet firmer. The finished round measured 8.56mm diameter consistently. The groups (and scores) weren't very good. I'm wondering if the bullets should be swaged out to .315"? MG4 barrel is .314.
My full length resize reduces the case about .002-.003 under bullet size.
I neck size to bullet dia .314 for the full length of the projectile (cast .314
BNBBWC), the brass spings back about .001-.0015 in diameter.
With heavy thumb pressure I can push about 1/2 into the case.
I crimp with .008-.010 of lead skirt exposed and reduce the diameter by
about .005 with the crimp.
The .38 load is similar with a .356 projectile for the Manurhin revolver.
It softens, and also lengthens the life of the brass by reducing the effect of work hardening caused by the case continually being belled and then crimped. I assume that the same principle applies with expansion from firing and then resizing.
Ordinarily the expansion from firing & then sizing doesn't work pistol brass too much, but the crimping process bends the brass a lot in a small area. I suspect a thin ring of brass could crack off after multiple firings. That could be very bad if it was in a semi-auto & stayed in the barrel.
Also, as the brass work hardens, the depth of the crimp & the tension will change, which could hurt accuracy. If you don't anneal every time you reload, you should probably sort your brass by the number of firings since the last annealing.
Big flat oven pan (at least case length deep), stand the cases neck up in the pan.
Fill with water to half way up the cases.
Use a gas flame, low heat yellow flame, warm the case necks to just change colour
then tip the case over into the water.
It is much easier to forget about annealing and just use new cases for big competitions.
