Crimping 9mm: a new thread for novices

[milprileb]

This is from one novice 9mm reloader to any others out there. If you are using cast bullets, this thing about crimp is going to ruin each and every solution you try for a accurate 9mm load.

I have gotten away with just swagging a crimp on 45acp cast loads and always had accurate loads. It was a non problem.

I have ruined many loads the past six months (alloys,charges, powder changes) due to crimp.

If you can feel the crimp, its probably too much ! When you do that, you are swaging that cast bullet and accuracy will go south.

When you crimp: its got to be a faint almost hairlike sensation which will diminish the flare ever so slightly and not swage you bullet.

So if you are having accuracy issues with 9mm, start lightening up your crimp and chances are, accuracy will improve significantly.

I am loading .358 sized bullets and it only takes a wrong crimp to undue that bullet size and have undersized bullets rolling down the bore ! I now have a almost molecular light crimp on these loads and they shoot awesome.

So light crimp means almost a breath !!

[HammerMTB]

Best to just remove the flare. As you say, no more than a very slight taper crimp is needed, and more will foul up more than it fixes.

[Colorado4wheel]

I never crimp inward on any pistol rounds. No mater the bullet. A inward crimp on a autoloader just is not needed. Not with a good sizing die providing enough neck tension.

[Doby45]

I crimp just enough for the round to chamber reliably in my barrel. The ole "very light crimp and drop in barrel test" I do this with 40cal, 9mm and 45..

[Dannix]

Good post milprileb.

For 9x19mm, I just de-flare. In fact, at times I just skip the crimp die altogether.

Oh, and another note for novice 9mm boolit guys: the Lee FCD is not your friend. FCD for riles = OK, FCD for straight/taper = Not OK.

[shovel80]

I use a Taper Crimp Die...I go slowly when setting up the crimp die...and Measure the diameter of the case at the neck with a dial caliper!...Just enough to bring the belling back down and No More!!
Terry

[Shiloh]

I just close the bell. No more.

Shiloh

[milprileb]

Too Little is better than too much. You can catch too little when
you check your rounds thru a case gauge or the empty (out of pistol) semi
auto barrel.

I never caught too much crimp... they always fed wonderously.

Anyhow, approach 9mm crimping from the light side first and your results will be rewarding.

I learned a very hard lesson on this: not proud of it but I sure would not wish anyone to repeat my errors.

[williamwaco]

I use my digital caliper to set my crimping die. I remove the flare just enough that the mouth diameter is exactly the same as the case diameter behind the flare.

As stated before, if you can see the crimp, it is too much.

[milprileb]

mouth diameter is exactly the same as the case diameter behind the flare.

Well, yes, no, maybe, perhaps and Who the heck knows with a tapered case like 9mm !

Just kiss the flare and if rounds chamber: you are golden. If not , add some more crimp.

I am not going on record to state how many rounds I have fired, how many loads, alloys, etc etc only to find my ham fisted crimping was defeating me for months.

I am going to state to novices: GO LIGHT and adjust from there. GO EXTRA LIGHT to almost infinitesimal crimp and adjust from that point.

This crimp thing is a killer IMHO with 9mm. Not so much a dynamic with 45ACP WITH ITS STRAIGHT WALLED CASE.

[milprileb]

PS: My long time Special Forces buddy who is a novice reloader lucked into the right charge and crimp and shot my LLA 124gr RNL bullets sub 1 inch at 25 yards. He did a fairy touch to the crimp and was in the winners circle. Me: I could not gain that result with my own bullets but he did. I asked for his crimp: it was so light that I was skeptical but tried it: WHAM... the lights went on.

It is a wake up call when someone can shoot your cast bullet and get accuracy and you cannot !

I am still flogging myself about this !

[PackerFan]

My lowtech method is to run my fingers down the bullet to the case when I pull it out of the sizing die. I can feel them catch against the top of the case, and that tells me that it'll headspace properly when in the chamber. Hasn't failed me yet.