Too tight crimp would affect accuracy?

[sargenv]

Actually, the Lee Factory Crimp die is kind of a sham. I've heard more people who use these things stop using them due to too much crimp being applied. You don't need a really tight crimp. You need enough of a friction fit that the bullet does not get seated deeper during feeding and also enough that the bullet doesn't "jump the crimp" and get longer when the gun recoils. Properly sized cases will generally have enough friction that this isn't a problem. On a semi auto that headspaces on the case mouth, you only need remove the bell and return the case mount to specification (for the 40 S&W, that is .4230", for the 9mm, it is .3800" (Speer #13).

[damndave]

Can you post some closeup pictures of a few rounds you've loaded? It might be obvious from those if they're crimped excessively.

[NotEnufGarage]

Actually, the Lee Factory Crimp die is kind of a sham. I've heard more people who use these things stop using them due to too much crimp being applied. You don't need a really tight crimp. You need enough of a friction fit that the bullet does not get seated deeper during feeding and also enough that the bullet doesn't "jump the crimp" and get longer when the gun recoils. Properly sized cases will generally have enough friction that this isn't a problem. On a semi auto that headspaces on the case mouth, you only need remove the bell and return the case mount to specification (for the 40 S&W, that is .4230", for the 9mm, it is .3800" (Speer #13).

I've found it to be very useful when using plated lead and hard cast lead bullets in 9MM and .45acp since a standard roll crimp can cause the case to cut through the plating material or cut into the lead enough to cause lead flakes to be created.

The FCD is also very useful for bottle neck cartridges when you're seating bullets without a cannelure, such as 110 grain JRNs in .30-30 for use in a lever action rifle. Without a good hard crimp, the possibility of bullet pushback in the magazine is very problematic. It might be that my sizing die expander pin needs polishing down, but I was able to push back bullets, both the 110 and some 150 JSP's with finger pressure. Luckily, there was enough powder in the case to keep the bullets from falling completely into the shell.

[NotEnufGarage]

That doesn't look like an excessive crimp to me, but only a caliper can tell for sure.

Does it seat in the barrel correctly?

[damndave]

Mine chamber and fire fine. I suppose you were asking the OP to post pics of his?

[Hornet_RN]

is crimping necessary for single loading ammo for a bolt action rifle?

i'm aware that crimping a completed cartridge is to make sure that the bullet doesn't move or get seated deeper as the action is moving, especially in a semi-auto or automatic firearm.

however, a previous post was wondering about crimping possibly affecting accuracy. especially if you OVER crimp.

but, i almost always single load for a bolt action rifle, so is it really necessary for me to crimp my ammo? i don't want it to affect my accuracy.

(FYI: i own two remington 700s, one in .30-06 and another in .308)

[sonnyt650]

It might be that my sizing die expander pin needs polishing down...

Maybe, but that's the other reason to use the taper crimp where the bullet itself is used as the mandrel. Realistically if every $4 deprime/expander pin was polished down to .001 tolerances as commonly expressed here, those businesses wouldn't exist for very long. The crimp can be adjusted alot more easily than expanders polished "to fix bad reloading practices". However I'm either preaching to the choir or deaf ears though -- not many people are undecided.

[sargenv]

For Pistols:

Roll crimps = Rimmed cartridges
Taper crimp = Semi auto actions, rimless or semi rimmed cartridges (38 super is semi rimmed but headspaces on the mouth of the case).

For Rifles I usually don't crimp depending on neck tension to hold the bullet. Otherwise I may crimp into the cannelure (if there is one) for semi auto rifles and lever guns. Single shots and bolt guns don't really need any crimp since they aren't being battered around much.

I can post photos but it'll take some time.. most of this information is readily available in any good reloading guide (Lyman, Speer, Hornady, Sierra, etc). I have never felt the need for any other after market crimping tool and generally depend on the seating/crimp die sold as part of the set.