Taper Crimp vs Factory Crimp

[Krazykarl]

Molon,

I agree with the accurate measurement of neck tension and I understand the elements that comprise neck tension. I am suggesting that a proper crimp must be considered in the equation.

[markm]

The necks are all trimmed with a Giraud trimmer which leaves a very kind chamfer bevel. Almost too much really.

And yes, the LEE FCD leaves no damage on the bullet if not set too aggressively. Very much agree with the neck tension measurement info. Nothing is more annoying to me than reading someone post neck tension in thousandths of an inch.

[markm]

I'm going to retest the NO Crimp/Taper Crimp too. I'm going to try 10 round groups, but I'm not good at shooting 10 like Molon. I just can't sit still and keep focus that long, but I'm going to try.

[triggerjerk]

I would be curious about bullet movement upon chambering among the three different methods. Take 3 or so each noncrimp, tapercrimp, FCD crimp and measure pre/post chambering for ogive length? I would advise simultaneous pre/post chamber headspace measurement also because headspace setback upon chambering (at least for me....) will affect that ogive measurement.

Or not.... Regardless, have a good shoot!

[markm]

These are 69 gr RMRs with IMR 3031. The taper crimp appears to help the cause.

[Krazykarl]

Nice work with that 10 shot group! Popular or traditional concepts are a good baseline until actual testing proves that the alternative idea IS viable. Thank you!!

[HKGuns]

I swapped scopes on my 20" rifle and sighted it in yesterday.

Not a 10 shot group, but I one holed this 5 shot 77gr LFC'd group loaded with XBR at 100 yards.

The one that isn't in the same hole was my last sight in shot, so not part of the group. I'm pretty satisfied with the results I get from the LFC.

[markm]

Nice work with that 10 shot group! Popular or traditional concepts are a good baseline until actual testing proves that the alternative idea IS viable. Thank you!!

I kind of wish I'd have shot 10 Lee FCD too. But 10 shot groups are an eternity.

I swapped scopes on my 20" rifle and sighted it in yesterday.

That's beautiful. PB's Geissele will shoot that good many days.

[triggerjerk]

Was really hoping to avoid new tooling and learning how to use it..... But I still appreciate what you are doing!

[markm]

Here's pic from the Sig Sauer ammo/thread with their Factory Crimp. They mash the jacket pretty hard. (Bullet is dirty from a bolt over on a suppressed AR.)