Hey Gang,
I'm more of a neck sizing long range kind of reloader, and proper crimping for autoloaders is new to me. I had to pull some loaded 95gr SSTs today, and the amount of distress on the bullet was surprising. (See below) I'm using the lee factory crimp die. Is this normal, or am I crushing it way too hard? FYI These bent up bullets are shooting around 1MOA over 30.6gr of H335, so it can't be THAT awful. Any information or advice would be welcomed.
B- Why are you crimping, normal neck tension should be all you need in an autoloader. I don't think I've crimped a single rifle case within the past decade.
I have recently begun to use a lee fcd for my 300 BO... it's the only Lee thing I think is worth the $$.
Having said this, yes that's too much crimp. The Lee fcd puts a radial crimp onto the bullet (horizontally all 'round the casing, vice a roll crimp onto the top edge of the brass) so the sides should not be digging in so deeply to the bullet shank.
Something's up.
I don't see a need to crimp any Grendel bullets. Just doing the BO b/c they are relatively heavy for cartridge size.
"Down the floor, out the door, Go Brandon Go!!!!!"
I only crimp some rounds to keep the bullets from moving either under recoil (revolvers and some lever guns) or feeding (some autoloaders). Also if that particular load needed a neck flare ironed out. That's excessive crimp. Those BT bullets shouldn't need any neck expanding and very little crimp if any.
05-22-2020, 12:12 AM (This post was last modified: 05-22-2020, 12:23 AM by FRB6.5.)
Believe it or not the ability to do that was one of the features Lee advertised when those dies were introduced. But as everyone has stated that is way too much crimp.
Edit:
It's still mentioned on both sides of the printed instructions even on the newer dies, but is no longer mentioned on the website for the product.
"You can seat your bullets to the best depth - the Lee Factory Crimper forms a cannelure in the bullet as it crimps."
and
"Bullets do not need a crimp groove as the Lee Factory Crimp Die will form one when crimping. However, it requires a harder push on the press lever to form the crimp."
With enough neck tension in an auto-loader you don't need the added step of crimping, and without the Lee design mangling your cases every time your cases will last longer and your group sizes will be no worse, probably better.
Enough neck tension is at least .002", especially if there a reasonable jump to lands. Your bullets can shift a tiny bit but as long as they don't come up against the lands there's no difference in start pressure to cause the classic split vertical group on the target. Another way of ensuring the bullets are less likely to shift is by having enough shank in contact with the neck. It helps if there's at least the diameter of the calibre in contact with the neck - so with Grendel at least 6.5mm of shank. You can check all this by measuring the before and after OAL of a round loaded into your AR when the BCG slams it into battery. If it doesn't shift or only slightly then you are good-to-go without needing to crimp.
Rounds loaded for the military and even factory rounds for civilian auto-loaders (e.g. Gemtech's 300BLK 220SMK subsonic) typically use cannelured bullets. This permits crimping into the void without damaging the bullet like in your photo. It's all about guaranteeing bullets won't budge with any amount of abuse, in any rifle. In your case you have the luxury of loading for one gun with known conditions. You don't need to be so severe.
FYI, Redding makes a taper crimp die for Grendel which covers more surface area of the neck and is a tapered effect. This means it is more forgiving on case length. It is also a lot less severe on the neck and the bullet.
Ok, No more crimping.
I'm on my third barrel trying to get my Grendel under 1 MOA. I was about to give up and sell it, but we'll see if going crimp free tightens up the groups....
Thanks for the great input!
GP
Oh wow! I just came on the ammo & reloading page to make a post of my own about crimping for the 6.5 Grendel. Someone - moretoys - already started the topic I was gonna start. The replies to his post pretty much answered my question about the need for crimping. I don't have the Lee FCD (didn't know Lee made one for the Grendel) but I do have the Redding taper crimp die. I guess I might not need it.
I was gonna ask about it for the Grendel 'cause I needed to start putting a slight crimp on the cases for my 7.62X40WT AR when I discovered there was some bullet movement during firing. Wilson Combat even recommended a little bit of crimp when I asked them about it.
I have a related question about Grendel brass but will start another thread.
I refuse to be victimized by notions of virtuous behavior.
moretoys Wrote:Ok, No more crimping.
I'm on my third barrel trying to get my Grendel under 1 MOA. I was about to give up and sell it, but we'll see if going crimp free tightens up the groups....
Thanks for the great input!
GP
MT,
I did a 300rd test a while back between taper crimping and neck tension. The groups are 4rds at 100yds, bench rested. Neck tension wins but to be real there's almost no difference.
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05-22-2020, 10:11 PM (This post was last modified: 05-22-2020, 10:13 PM by FLshooter.)
When I used sizing dies that also crimped,I used to put a small crimp on all ammo going through an AR. But once I got the Forster dies,which do not crimp, I stopped doing it. And I must admit I really didnt see a difference.My hand loads are a little more consistent now.But that is probably due to my CoAx press.
I only use a light crimp on the cannelure for hot loads in revolvers. I once had a S&W 686 .357 lock up (9gr. unique, 125gr. xtp...way too hot for a S&W!! I now only shoot this load in a Ruger Blackhawk) when a bullet jumped and bound up the cilinder. I've been crimping revolver loads ever since.
Im a crimper - always have been and always will be.
I like the added buffer between me and pressure spikes due to bullet setbacks during recoil.
For loads that I dont crimp - very rare - I will discard the chambered round after 2 or 3 chamberings (hunts that didnt produce a shot).
Really it is quite simple .
Chamber a round 10 times , crimped and uncrimped and measure the OAL. Crimped shouldnt move - uncrimped (Handloads) will probably move.
Apply just enough crimp to pass this test and carry on.
DO sacrifice a firing pin and when youre chambering these loads at home use a cut tip firing pin that allows the BCG to operate but in no way contacts the primer - safety !
Lastly, I have some pretty accurate loads in many chambers that have been crimped - I have a box of .30 cal Berger bullets that look like yours after pulling them down. Is it too much crimp - yea probably, thats why I now test like I outlined above or just crimp by feel now.
In any case youre on your third barrel and deciding to crimp or not but I would ask -
Have you been trying different COALs of the same charge weight to see if that tightens your groups and what method are you using to see how far off the lands your bullet ogive is.
These two things will change accuracy much more than crimping, or not.
I have been using the FCD for 6 or 7 calibers ever since I started reloading over 20 years ago. I've never had a bullet look like that. I HAVE had some that had more crimp than needed when I didn't follow the instructions that come with the FCD. I'm not an expert on the subject(probably shouldn't even comment) . I reload so I can better afford to shoot hogs. That's pretty much all I do anymore. Don't need extreme accuracy, but I like to get the loads as good as I can. My equipment is not the most expensive, but if I do my part, it produces single digit spreads. I can tell that the neck tension is not the same on my cases when seating the bullet, and I think the FCD helps make the tension more consistent. Don't know if that's right or not, it's just the way I do it, works for me.
. I reload so I can better afford to shoot hogs. That's pretty much all I do anymore. Don't need extreme accuracy, but I like to get the loads as good as I can. My equipment is not the most expensive, but if I do my part, it produces single digit spreads. I can tell that the neck tension is not the same on my cases when seating the bullet, and I think the FCD helps make the tension more consistent. Don't know if that's right or not, it's just the way I do it, works for me.