Bullet moving in the case when chambering

[Bgd]

I just noticed that the bullets are moving forward in the case when chambering in my ar. I think this is what my problem has been. I just ordered a RCBS AR die set with the taper crimp die. I think the problems will stop.

[FOB]

A bent decapping pin can cause that.

[plant.one]

the crimp die that most of us are using is the Lee Factory Crimp Die.

they're very easy to setup and 'normalize' your neck tension with.

[smustian]

the crimp die that most of us are using is the Lee Factory Crimp Die.

they're very easy to setup and 'normalize' your neck tension with.

Second the Lee Factory Crimp die.

[hardcase]

Lee crimp die works well in my Dillon 550B as well.

[DoubleJ]

Fourth Lee FCD, it'll even create a little cannelure if your bullet doesn't have one. I don't mind smooshing the Palmetto 203s, they're just for fun.

[Bgd]

Does the FCD work better than the RCBS taper crimp AR die?

[smustian]

Does the FCD work better than the RCBS taper crimp AR die?

Does the same job at less than 1/2 the cost.

[cwlongshot]

The FCD is a collet crimper. It crushes the sides of the case into the bullet.

The Taper crimp is just that, a tapered area that reduces diameter so the mouth of the case is pressed int the bullet.

I am NO fan of the FCD. To me its the answer to a unasked question. Every set of dies out there has all the crimping one will need. Only real reason I see for a second crimping die is when using a progressive press, where (and you should always) crimp in a separate stage.

CW

[dellet]

The FCD is a collet crimper. It crushes the sides of the case into the bullet.

The Taper crimp is just that, a tapered area that reduces diameter so the mouth of the case is pressed int the bullet.

I am NO fan of the FCD. To me its the answer to a unasked question. Every set of dies out there has all the crimping one will need. Only real reason I see for a second crimping die is when using a progressive press, where (and you should always) crimp in a separate stage.

CW

This is completely backwards, or requires some explanation in regards to word choice.

On a collet die like the Lee FCD, the neck enters the collet, which is then pressed against the neck of the cartridge. This is a true pressing action which will only crush the bullet if it is not adjusted correctly. The idea is uniform tension the length of the neck.

A taper crimp is no different than a bullet sizing die in that you are forcing a larger diameter through a smaller hole that is tapered. This is actually more of a crush than a press and can still be over done. Without a cannelure, and/or fairly exact trim lengths and brass thickness, tension will vary widely.

If your neck tension is set correctly by adjusting sizing ball diameter, then the need for crimping becomes a choice. Smoothing out a bell is a different action all together.

I polish the sizing ball to .305"-.306" and have no problems with 175 grain bullets, on compressed loads moving when chambering. Always with ES in the low to mid teens with single digit SD.

If I were the OP, diameter of the sizer would be the first thing I would check.