Crimp question

[Dildobaggins]

So I know this has been run over and then backed up on, and run over again. But I can't really find anything concrete. These are for an ar15. I FL sized all my Winchester and Lapua brass, then ran them through a PMA mandrel. All of them are .220 inside diameter. (Very nice mandrel btw) I have a Lee crimp die. Would it be necessary? I know alot of people run .002 and they say that's optimal. I seated a round without a primer and powder and beat the shit out of it by slamming it on concrete trying to get it to telescope back into the case and it didn't move. I saw something on here saying Hornady does not use a crimp on alot of the ammo, because it's the I.D of the case is .004 smaller than the projectile. Any advice? Should I crimp these, or should I be good? Thanks

 

[alamo5000]

Crimping is optional. Even for an AR15. (Of course it depends on the details).

Some organizations (like the military) want ammo that is bullet proof and can withstand being thrown out of a helicopter or the back of an airplane, or that will be shot out of a variety of guns including the peeeew (I'm out) variety. For regular use crimping is not needed, at least until you find a reason to do so.

However it's worth noting that if you run extremely light neck tension it can cause problems in a semi auto.

If you want to be 100% certain that your bullets do not move when going through the chambering process then crimp away. If you have questions then make a couple of rounds and chamber them in the hardest way possible. Remove them from the chamber and measure if the bullet has moved or not. If the bullets didn't move then no problem. If they did it could be reason to crimp.

 

[Huskydriver]

Depends on how much the bullets move under recoil....on my ar loads I have bullets that move under recoil with .006 neck tension but its minimal by the end of the mag. With .002 I would have serious oal issues.

Crimping can cause velocity and pressure issues too so confirm that with your load dev

 

[alamo5000]

Depends on how much the bullets move under recoil....on my arm loads I have bullets that move under recoil with .006 neck tension but its minimal by the end of the mag. With .002 I would have serious oal issues.

Crimping can cause velocity and pressure issues too so confirm that with your load dev

Exactly.

Telling someone to do it or not in a yes or no manner isn't going to work out. I almost never crimp. I used to crimp all the time. It's not an absolute yes/no type thing.

 

[Dildobaggins]

Exactly.

Telling someone to do it or not in a yes or no manner isn't going to work out. I almost never crimp. I used to crimp all the time. It's not an absolute yes/no type thing.

So does that mean I should crimp or not? Lol jk

 

[Shoots 700's]

On a gas gun I don't crimp, unless it’s 55 fmj for blasting. however I do use .004-.005 on neck tension For more precision rounds.

Works for me, not for everyone

 

[whatsupdoc]

Lets use some common sense, load a mag with OAL measured rounds
shoot the first then manually eject the chambered round put that aside. Do the same thing three or four
times.

Measure the OAL of the loaded rounds that were chambered and manually ejected.

Bullets did not move = nothing to see here.
Bullets moved a little = some further investigation may be required.
Bullets fell out and powder everywhere = son you messed up.

 

[Choid]

For ARs run a NOE expander at 226 mouth-222 neck, then run a Lee FCD to crimp the case mouth to 1-2 thou smaller than loaded neck diameter. Especially if you are loading on a progressive with a bullet feeder. In my experience it gives he best combination of accuracy with no movement in the magazine.

Crimps do a minimal amount to keep the bullet in place. Some people say it does nothing, but they are wrong. What they do in a semi auto is to facilitate better feeding. People have a hard on for mandrels for everything, but they have a time and place, and it really isn't loading 223.

 

[Dildobaggins]

For ARs run a NOE expander at 226 mouth-222 neck, then run a Lee FCD to crimp the case mouth to 1-2 thou smaller than loaded neck diameter. Especially if you are loading on a progressive with a bullet feeder. In my experience it gives he best combination of accuracy with no movement in the magazine.

Crimps do a minimal amount to keep the bullet in place. Some people say it does nothing, but they are wrong. What they do in a semi auto is to facilitate better feeding. People have a hard on for mandrels for everything, but they have a time and place, and it really isn't loading 223.

I'm very new to reloading. These are my first 200 rounds I'll be loading. Trying to find a video or instructions on the Lee FCD and can't find any. I'd like to put a light crimp on them but idk how to make it do that but more importantly how to replicate it when I take it out of the single stage press I have.

 

[Choid]

I'm very new to reloading. These are my first 200 rounds I'll be loading. Trying to find a video or instructions on the Lee FCD and can't find any. I'd like to put a light crimp on them but idk how to make it do that but more importantly how to replicate it when I take it out of the single stage press I have.

The Lee FCD for rifles is a collet crimp, so it is going to be easier to recreate. You just screw it down until it stops on the shellholder, then llower the ram and screw it in about a half a turn more. Then test it. When you know the total you turned it down after hitting the stop, write that down, and you will be able to recreate it next time.

 

[rustyinbend]

The Lee FCD for rifles is a collet crimp, so it is going to be easier to recreate. You just screw it down until it stops on the shellholder, then llower the ram and screw it in about a half a turn more. Then test it. When you know the total you turned it down after hitting the stop, write that down, and you will be able to recreate it next time.

This is exactly what I do for my 300-BLK (AR-15) and 6.5-CM (AR-10) semi-automatic rifles ... and the Lee FCD works great and is easily reproducible. I just leave mine in my T7 Turret Press right next to the Seating Die for both of these. And no crimp for my bolt action rifles ... of course.

 

[Choid]

This is exactly what I do for my 300-BLK (AR-15) and 6.5-CM (AR-10) semi-automatic rifles ... and the Lee FCD works great and is easily reproducible. I just leave mine in my T7 Turret Press right next to the Seating Die for both of these. And no crimp for my bolt action rifles ... of course.

I know it is sacrilege to do so, but I wonder what the actual effect of crimping in bolt guns is. It's pretty clear there is a lack of theoretical benefit, but I wonder if anything bad, or good, actually happens.

 

[Huskydriver]

I know it is sacrilege to do so, but I wonder what the actual effect of crimping in bolt guns is. It's pretty clear there is a lack of theoretical benefit, but I wonder if anything bad, or good, actually happens.

For me it always blows es and sd up

 

[Dildobaggins]

The Lee FCD for rifles is a collet crimp, so it is going to be easier to recreate. You just screw it down until it stops on the shellholder, then llower the ram and screw it in about a half a turn more. Then test it. When you know the total you turned it down after hitting the stop, write that down, and you will be able to recreate it next time.

That's exactly what I do with my FL die. Thanks alot man! Couldn't find any videos on it. Everyone rambles for 10 minutes and doesn't show you what to do haha

 

[MakeSawdust]

I know it is sacrilege to do so, but I wonder what the actual effect of crimping in bolt guns is. It's pretty clear there is a lack of theoretical benefit, but I wonder if anything bad, or good, actually happens.

I have not done it for long range stuff. When my only purpose for CF rifles was to kill coyotes, I crimped everything. I know this is not extremely demanding of the load, but I used to shoot sub 1/2" at 100 yards, sub 2" at 400 yards, and sub 4" at 500 yards for 3 shots (I was a fudd and didn't know any better.) 500 yards is the furthest I ever shot until shortly before I started shooting PRS. All the rounds were crimped very tight. I tightened the die until the collets almost closed. I found this produced the best accuracy on the first load I tried it on. I adjusted the load with powder charge and seating depth and left the crimp alone. I still do this for AR-15 blasting ammo. It shoots sub MOA at 100 yards. I have no precision ARs and no experience loading for those.

When I started shooting long range I tried all of the black magic loading techniques that everyone espouses and chased my tail for awhile. I have pretty much figured it out now, but there is no black magic. I do not crimp bolt action stuff for long range. My most accurate gun is a 6 Dasher that will consistently shoot 1/4 minute off of a bipod and rear bag. I am a shitty group shooter, so that means the gun and load are incredibly good. I full length resize using a Forster FL die and seat bullets with the forster seating die that comes with the set. Lapua brass, berger 108s, and Varget, no magic. All of this is done on a cheap Lee single stage press. SD varies but is always sub 8 (sometimes 5 or 6) and ES runs between 20 and 30 (it's sometimes sub 20, but that is for 5 shots usually so not probably true for statistically significant sample sizes.)

My point is, this stuff is way more simple than everyone wants to admit. Do a little testing and find out what works for you. Most of the accuracy equation is in the rifle. You need a concentric chamber and the gas system worked out in a semi. After that you need great brass and great bullets. With those things you can load 1/4 minute ammo with basic dies and presses. The black magic comes into play when all of that stuff is sorted out and you are trying to get from 1/4 minute to groups that start with 0.0XX."

I really have no desire to shoot precision semi-auto, but if I did I would experiment with more and more neck tension and watch for bullet setback as well as accuracy variations. I would also experiment with the Lee FCD and watch for the effects on accuracy in comparison to the uncrimped ammo. For blasting ammo, my $0.02 is to crimp the shit out of it. I can grab my AR with a 1-4x scope and hit 2 moa targets out to 600 with surprising consistency. There is no need to make things complicated unless you are looking for better than practical accuracy.

I read the OP again and will add, having good brass that is consistent is very important for top accuracy. I would separate the 2 brass types at a minimum, or maybe even just use Lapua to get to precision.

 

[r.tenorio671]

This is exactly what I do for my 300-BLK (AR-15) and 6.5-CM (AR-10) semi-automatic rifles ... and the Lee FCD works great and is easily reproducible. I just leave mine in my T7 Turret Press right next to the Seating Die for both of these. And no crimp for my bolt action rifles ... of course.

...the only caveat with the Lee FCD is the thickness of the neck, especially if using various cases, like 1x fired brass bought off the internet of various brands and/or datestamps (LC) that hasn't been neck-turned.

...the method I prefer is to run the ram up all the way, THEN screw the LEE FCD down until it contacts the mouth of the casing. The Lee FCD is open at the top, giving you an unobstructed view looking down into it so you can see when the case mouth makes contact and when the collet begins closing around the case mouth applying the crimp. Easing the force on the handle can allow you to just screw the die down and feel its movement through the handle, its a minor movement. While peering down into the die when you re-apply force you will see the casing move up and the collet begin applying the crimp by the gaps in the collet closing (a very slight change in appearance). I found that doing it this way, running the ram all the way up, was more consistent ( I use a progressive). If you trim consistently, case length growth from brass flow is a minor consideration, but still a factor to watch for.

YMMV

Edited: BTW, you can measure the circumference of the casing neck before seating a bullet, after seating a bullet and then after applying the crimp to extrapolate how much "neck tension" was applied...if you really want to go down that rabbit hole. I have seen cases where seating a bullet expanded the neck circumference a measurable amount...

 

[Dildobaggins]

...the only caveat with the Lee FCD is the thickness of the neck, especially if using various cases, like 1x fired brass bought off the internet of various brands and/or datestamps (LC) that hasn't been neck-turned.

...the method I prefer is to run the ram up all the way, THEN screw the LEE FCD down until it contacts the mouth of the casing. The Lee FCD is open at the top, giving you an unobstructed view looking down into it so you can see when the case mouth makes contact and when the collet begins closing around the case mouth applying the crimp. Easing the force on the handle can allow you to just screw the die down and feel its movement through the handle, its a minor movement. While peering down into the die when you re-apply force you will see the casing move up and the collet begin applying the crimp by the gaps in the collet closing (a very slight change in appearance). I found that doing it this way, running the ram all the way up, was more consistent ( I use a progressive). If you trim consistently, case length growth from brass flow is a minor consideration, but still a factor to watch for.

YMMV

Edited: BTW, you can measure the circumference of the casing neck before seating a bullet, after seating a bullet and then after applying the crimp to extrapolate how much "neck tension" was applied...if you really want to go down that rabbit hole. I have seen cases where seating a bullet expanded the neck circumference a measurable amount...

Good info! Thank you!