To crimp or not to crimp?

rush709

New member
I guess this is dependent on different factors, but was wondering what peoples opinions on this were. From what I been reading they're required in an auto or tube magazine rifle, and it has it's positives and negatives.

I crimped the bullets I've loaded so far. Mainly because the Lee manual says that it's preferable for hunting purposes. But also because time I gone done seating bullets on the 40 I've done yet I thought to myself "I'm out of cases now but I dont want to leave the bench yet, what else can I do?"

It was the Lee factory crimp die I used, and I only put a slight crimp on them.

Also noticed in the Lee manual that it says a crimp can help reduce differences cause by temperatures. Anyone have any experience with that?

It's bolt guns I'm shooting with, so the crimp might not be a necessity...
 
On my bolt guns, I very seldom do any crimp work in addition to the one in the initial seating die...I do, however, keep a close eye on my neck tension from initially seating the bullet...On light recoil rounds, I can get by with .001" of neck tension, but on my semi autos and heavier recoil rounds, I like .003-.004" of neck tension..
 
I've never crimped a round for bolt guns. Haven't needed to. If you are crimping and and it's working for you I say go for it. Probalay no right or wrong answer,just adds one more step for me, which I don't need
 
Originally Posted By: dpollardI've never crimped a round for bolt guns. Haven't needed to. If you are crimping and and it's working for you I say go for it. Probalay no right or wrong answer,just adds one more step for me, which I don't need

Yea, seems to be no set in stone right or wrong answer. I'm doing pretty low volumes, and I'm new and eager to reloading so I was happy to add an extra step. Eventually I may do some comparison crimped vs uncrimped loads, but for now I'll probably keep doing a light crimp at least.
 
I dont crimp for any bolt gun. I also dont crimp for my ar's, never had any problems. I agree with the above statement of focusing on neck tension.
 
i run lee FCD's on most of my calibers, but its as much because i have an open station on the press as it is for anything else. I see it as an easy way to "normalize" neck tension, and only have it set for a light crimp (usually about ¼ turn or less after touching the case mouth)


if you're loading cast, or plated and need to bell the case to seat them without damaging the bullet you'll need to use a crimp die to remove the belling you did to seat the bullet.
 
I never crimped a rifle round in my life, been loading since '68 with the exception of 44 mag, 30/30, 444 Marlin, and 35 Remington. Never crimped an AR round either, but I know how much neck tension I have on the loaded round.

Crimping is a bona fide science in and of it's self, lots of factors introduced that can vary pressure.

Chances are that if you are crimping your rounds, you are not searching for the extremes in accuracy because the two do not go hand in hand with each other. What one guy calls accuracy, another guy calls a shot out barrel...your hobby...you pick.

Concerning the crimping, Lee collet dies are the way to go. Best avoid crimping like the plague. If you are in the habit of belling your case mouth with a Lyman P A die or other die, then a very slight crimp like Plant.one is the way to go.

Crimping screws up a lot of rifle reloaders!

So, many may ask, "how do I know if I have to crimp or not crimp". Answer is easy. Put a loaded round in your reloading press with no die in the press. Raise the ram of the press where the round is sticking up, and place a 1" or larger washer over the bullet, and grab the bullet with a pair of pliars. Now, lower the ram while gripping the bullet. If the bullet pulls out real easy, then you may need to crimp, or better yet go to a smaller bushing in a bushing die.

In the vast majority of the cases, the bullet will be mangled very badly by the extreme grip on the pair of pliars indicating that there is ABSOLUTELY no need in a crimp.
 
Originally Posted By: ackleyman

Chances are that if you are crimping your rounds, you are not searching for the extremes in accuracy because the two do not go hand in hand with each other. What one guy calls accuracy, another guy calls a shot out barrel...your hobby...you pick.



So, many may ask, "how do I know if I have to crimp or not crimp". Answer is easy. Put a loaded round in your reloading press with no die in the press. Raise the ram of the press where the round is sticking up, and place a 1" or larger washer over the bullet, and grab the bullet with a pair of pliars. Now, lower the ram while gripping the bullet. If the bullet pulls out real easy, then you may need to crimp, or better yet go to a smaller bushing in a bushing die.

In the vast majority of the cases, the bullet will be mangled very badly by the extreme grip on the pair of pliars indicating that there is ABSOLUTELY no need in a crimp.

Currently I'm not in it for extreme bench rest accuracy. Sure, I want good accuracy, but I dont do much bench rest shooting, and in practical terms, for the distances I'm hunting, a 1" group wouldnt be much different to the animal than a
 
I don't crimp on rounds for a bolt action.
Only crimp the 300 BLK for AR cause one projectile moved into the groves on a slam feed
then stuck on extraction dumping powder into the action, on a hunt.
Think the quality of brass for 300 BLK is mixed so its just a precaution I take.
(And some people consider the 300 BLK a pistol round anyway)
 
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Just because you want accurate ammo, does not mean that you are a benchrest shooter.

Your assessment is spot on, a 1" group is adequate, only when ranges go over 200 on small pest animals require more, or you can just sling enough lead at them till you hit something.
 
Originally Posted By: ackleymanJust because you want accurate ammo, does not mean that you are a benchrest shooter.



You're right there, I guess I worded what I meant wrong. Just meant that personally, most of my shooting is in field conditions and squeezing an extra half inch tighter isnt going to make or break my shots 99% of the time. Not saying that extra accuracy is a bad thing by any means, and it would certainly be something to strive for. I just dont think I'm equipped with enough high end gear to really notice. Though I can already feel this reloading hobby making me want upgrades.
 
Great strides in accuracy can be made with little effort, establish OAL to the lands, firs step.

Before you go down this road, bed the action, free float the barrel, adjust the trigger to your standards, otherwise you MAYBE chasing your tail.

A lot of hunting does not require all this attention to detail, kinda a hobby within a hobby. What ever you do, make it fun for you. If you enjoy the pursuit of accuracy, then do it on a level and in steps that is not overwhelming to the fun factor.
 
i always recommend doing any bench testing with a dummy round - just brass and bullet. leave the powder and primer out.

do everything else the same and use that finished empty brass + bullet to test with.

one of the tests i've used to check neck tension.... make up a dummy round, hold the brass in your hand with the point facing away from you and the tip of the bullet sticking out of your closed fist. bring your hand down in a stabbing motion so the tip of the bullet strikes your bench or something similarly hard. Measure OAL after a couple good solid impacts with the bench. if no movement, you're probably going to be ok.

the other test i've used is - again with a dummy round, no powder or primer - is to load one up, measure the OAL and then chamber it a dozen or 15 times. Make sure you drop the bolt from bolt lock, which is probably the closest you'll get to actually cycling under normal operation.



If you get an OAL change, repeat the test and measure after each chambering. If you want you can measure OAL every charge and save possibly repeating this step.


generally speaking, if you can get 3-5 charges with no OAL change you're probably just about where you need to be to ensure you dont get setback during normal operation of your gun. Realistically speaking, no bullet should be in/out of your chamber more than that, unless of course you're hunting and not having much luck.

i try to never chamber a loaded round more than 5 or 6 times before it gets cycled down into the bottom of the magazine, just to be overly cautious, even though i'm comfortable i'm not getting any setback through my measuring tests.

HTH
 
Only rounds I've ever crimped were pistol. I've loaded and shot a LOT of rifle rounds, thru bolts and AR's never using a crimp.
 
Originally Posted By: tonybI would never crimp. Too big a chance for inconsistent pressures...

Tony.

+1

Real obvious in the groups.
 
I'm not an expert, so take the following FWIW.

I've never used a separate crimping step (I just use the seater die), and so far have never had an issue even in my .300 WM bolt gun. However, before going afield I check hunting rounds by pushing them against the table.

As far as ARs, I can't imagine the rounds being affected much by recoil.

My rifle looney friend had the following advice: (1) If you're going to crimp, don't do it until you've trimmed them all equally after firing. (2) Start with a light crimp and compare groups and velocities with uncrimped rounds.
 
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