To crimp or not to crimp that is the question

[jack44]

In a hard recoile rifle like the 1895 45/70 crimp for SAFETY reason dont want your bullet to go in side the case also they say you get better your rifle more
accurate.

 

[steve4102]

I am not saying crimping or not crimping is more accurate but one 5 shot group is not enough data to come to a valid conclusion.

The more data the better. Statisticians can design an experiment that determine a minimum amount of data required to have statistically valid results.

Here is another Accuracy test done by the guys over at the Accurate Reloading Forum. Note the increased accuracy!

http://www.accuratereloading.com/crimping.html

 

[cfullgraf]

Ok, compelling information. But still not enough data to make the blanket statement "crimped rifle rounds have better accuracy over un-crimped".

Considering it is known that different rifles get better accuracy from different powders, diffrent loads, different bullets, and a host of other variables, why not some do better crimped and some un-crimped.

 

[Walkalong]

But still not enough data to make the blanket statement "crimped rifle rounds have better accuracy over un-crimped".

Yep, way to many variables to say one or the other is always best.

 

[rskent]

Rhino said it best
“Problems with neck tension are not solved with crimp”
Have a great Day
Steve

 

[Walkalong]

“Problems with neck tension are not solved with crimp”

Which is 100% true.

 

[steve4102]

Ok, compelling information. But still not enough data to make the blanket statement "crimped rifle rounds have better accuracy over un-crimped".

True, but it is compelling enough to disprove the blanket statement "crimped rounds will distort the bullet and degrade accuracy", yes.

I will go out on a limb here and say that without a doubt (blanket statement) the use of the Lee Factory Crimp die improves accuracy in MY semi-auto rifles. YMMV.

 

[lead slinger]

I crimp everything I reload weather it's a feeding or just to keep all my ammo on a even plain. I pick up alot of range brass and alot of the 223 I get the bullet just drops right though the case so I do a two stage decap/resize then it run it though a lee neck sizing die

 

[EddieCoyle]

A crimp will help even out groups when you're using mixed brass (mixed headstamps, lengths, and # of times fired).

I could find no difference between crimped and uncrimped rounds when my brass was sorted by headstamp, number of times fired, and trimmed to the same length.

As far as increasing neck tension goes, if you undersize the necks to more than about 0.0025" under bullet diameter, you're wasting your time.