To crimp or not to crimp

[timberghost72]

Well after alot of reading on the interweb I thought I'd ask here as there is a wealth of info from all you guys. I am wondering when to crimp and when it is not needed. Here are the calibers and guns I am reloading for.

30-06 and 300 WSM both bolt action rifles using Barnes bullets no cannelures

.45 ACP shooting from semi-auto pistols various plated round nose bullets

38/357mag shooting from revolver. Haven't loaded this yet so no bullet picked out.

Roll or taper crimps if any of these should be crimped.

From what I understand the rifle bullets don't need to be crimped if in a bolt action rifle. Semi-auto do need crimping.

.45 should be crimped?

Thanks

[carpsniperg2]

Crimp your handgun rds the rifles do not need a Crimp IMHO. I only crimp 1 rifle and it has about 13000 lbs of energy.

[wadu1]

I only crimp 45-70 they just group better crimped; and my 9mm and 45 ACP are crimped

[lokidog]

I don't crimp my -06, one more variable to add IMO.

[Todd_ID]

Crimp your handgun rds the rifles do not need a Crimp IMHO. I only crimp 1 rifle and it has about 13000 lbs of energy.

Can you clap with your shoulder blades after shooting it?

This is something I've been wondering about, too.  I just started loading this week.  The Lee die set came with a "Factory Crimp Die", and I'm not to sure what to think about it.  The die instructions say that Speer doesn't recommend using it with their bullets, and I'll likely use only their stuff since they're made here in town, so I didn't know what to do.  I crimped the Hornady bullets but not the Speer; maybe I should load some more Hornadys to see how the groups change.

[Heredoggydoggy]

Straight walled rimless cases like 9mm, .40 s&w, .45 ACP headspace on the case mouth, so should not be crimped too much.  Bottleneck rifle, and a few pistol cases, like the .357 SIG, headspace on the shoulder of the case, so crimping is not as critical.  Revolver cases, 38/357, 44 Mag, 45 Colt, etc, headspce on the rim of the case.  Crimp 'em all you want.  Bullets with a cannelure like the military .223 FMJs are crimped to keep the bullet from being pushed into the neck of the case when it hits the feed ramp.  Also hunting rounds like the 30-30, that load into a tube end-to end are cannelured and crimped so recoil doesn't push the bullets into the case.  I load a lot of .223 cases for my AR 15s with non-cannelured bullets, and as long as they seat firmly in the case neck, there is no need for crimping.  The only rifle round I've found to need a crimp die is my .450 Bushmaster, because the seating die doesn't give the round much "crimp" pressure, and they won't fully chamber in the gun.  Using the crimp die Hornady provides in the die set seems to solve the chambering problem.  Sometimes in reloading it's a case of seeing what works best in your test rounds, and adjusting accordingly.

[C-Money]

I crimp my 357mags. I shoot Hornandays hollow point, 158gr XTP.

[JKEEN33]

Straight walled rimless cases like 9mm, .40 s&w, .45 ACP headspace on the case mouth, so should not be crimped too much.  Bottleneck rifle, and a few pistol cases, like the .357 SIG, headspace on the shoulder of the case, so crimping is not as critical.  Revolver cases, 38/357, 44 Mag, 45 Colt, etc, headspce on the rim of the case.  Crimp 'em all you want.  Bullets with a cannelure like the military .223 FMJs are crimped to keep the bullet from being pushed into the neck of the case when it hits the feed ramp.  Also hunting rounds like the 30-30, that load into a tube end-to end are cannelured and crimped so recoil doesn't push the bullets into the case. 

+1

[carpsniperg2]

Crimp your handgun rds the rifles do not need a Crimp IMHO. I only crimp 1 rifle and it has about 13000 lbs of energy.

Can you clap with your shoulder blades after shooting it?

This is something I've been wondering about, too.  I just started loading this week.  The Lee die set came with a "Factory Crimp Die", and I'm not to sure what to think about it.  The die instructions say that Speer doesn't recommend using it with their bullets, and I'll likely use only their stuff since they're made here in town, so I didn't know what to do.  I crimped the Hornady bullets but not the Speer; maybe I should load some more Hornadys to see how the groups change.

You must be strong like bull!!! A nice fish gill and big recoil pad help   I use the lee crimp on that gun. It works well, The hornadys are the bomb in that gun I wish my friends at nosler would make a bullet for me A nice fat etip would be great

[jaymark6655]

I crimp anything that will be used in a semi and then my hunting rounds.  There is something important in the Lee Manual about why it is good to crimp, but I am too lazy to walk down three stories to look it up.  I do remember that it has to do with the way pressure in the case builds up and that you can obtain the same thing by seating just off the rifleing.  I do this with my target rounds just because I only load one at a time, for hunting the cartridge would be too long to fit in the mag.

[KillBilly]

if you don't crimp you can actually rattle/vibrate your rounds back into the case. I have read that all hunting rounds should be crimped and the primers sealed to prevent any moisture from getting in. I don't seal my primers but I do crimp every round I load.

[JackOfAllTrades]

Semi auto cases that headspace on the case mouth should be lightly taper crimped.

Magnum pistol and other straightwall rifle cases should have a moderate to heavy amount of roll crimp into the cannelure.

Lighter pistol and straightwall rifle cases should have a moderate amount of roll crimp into the cannelure.

Bottle neck cases for single shot and bolt action rifles with bullets that do not have a cannelure should be moderately crimped or not crimped at all.

Bottle neck cases for leaver action rifles and semi-auto's should be roll crimped into the cannelure of the bullet.

For any given situation, there can be 'too much crimp', just as there can be 'not enough crimp'.

-Steve

[Ray]

I put a small crimp to my .44 mag loads. When reloading all other ammo for the guns I own, I do not crimp.

[BlackRidge]

Good info

Is it safe to assume you've given a round too much crimp if its alterred the shape of the bullet at all, or is some ok/to be expected?  (i.e pinch it inwards slightly at the crimp point)

[KillBilly]

if you don't crimp you can actually rattle/vibrate your rounds back into the case. I have read that all hunting rounds should be crimped and the primers sealed to prevent any moisture from getting in. I don't seal my primers but I do crimp every round I load.

When I first built my 7MM STW, it was still wildcat and I had a guy from Michigan professional loading my ammo for me. He did not crimp any of it and I lost a bunch of rounds due to the bullets falling back inside the case mouth. So, I always crimp every round I load.

[KillBilly]

Good info

Is it safe to assume you've given a round too much crimp if its alterred the shape of the bullet at all, or is some ok/to be expected?  (i.e pinch it inwards slightly at the crimp point)

If you follow the instructions on setting your dies, you will not deform any cases. In some instances, I use a seater/crimper and for other applications I use a crimping die after seating. if you get deformation, re-set your die.

[sakoshooter]

I don't crimp any of my rifle ammo.

[JackOfAllTrades]

I don't crimp my bottleneck rifle ammo either, but we need to realize that we're discussing this with a new reloader. The books say to crimp. The die's are designed to crimp.

We should support that.  If we don't, we should explain why we do not, to teach the new reloader reading this thread.

I do not crimp my bottlenech rifle loads because they are not fed in a tubular magazine and I have experienced less standard deviation of bullet velocities for my reloaded/chronographed cartridges, leading to better accuracy.

-Steve

[Heredoggydoggy]

if you don't crimp you can actually rattle/vibrate your rounds back into the case. I have read that all hunting rounds should be crimped and the primers sealed to prevent any moisture from getting in. I don't seal my primers but I do crimp every round I load.

When I first built my 7MM STW, it was still wildcat and I had a guy from Michigan professional loading my ammo for me. He did not crimp any of it and I lost a bunch of rounds due to the bullets falling back inside the case mouth. So, I always crimp every round I load.

If your bullets rattle/vibrate back into the case, it means the brass is too hard to adeqately grip the bullet, and the case necks need to be annealed.  If you notice, all the military Lake City brass has a heat coloration on the neck of the brass.  this is due to the annealing process, presumably to insure that the case necks are not too hard to grip the bullet, and jam the gun in the heat of battle.  Annealing is a simple process that can be done at the home shop, if needed to soften case necks.  I once had a lot of 30-30 brass that had necks so hard they wouldn't even hold a crimp.

[timberghost72]

Thanks for all the info guys. Looks like I am going the right direction. I'm gonna hold off on crimping my rifle rounds and keep the crimp on the pistol rounds.

[JimmyHoffa]

I get the opposite as Jack of All Trades...I find that crimping reduces my SD.  Also, find that primer types help reduce the SD.  So not sure how much of my variance is due to primer and how much to crimp.  Whenever I have a cannelured bullet I'll crimp.  Most of my hunting ammo is cannelured.  The weird fancy bullets I have don't have cannelures so, it's not an option for my press.

[JackOfAllTrades]

Whenever I have a cannelured bullet I'll crimp.

I should have caught that one.  I said "I don't crimp my bottleneck rifle ammo". I would if I reloaded 30-30 for tubular magazine. If the bullet seating depth is such that allows a crimp into canelure, I would, such as I used to for my son's 243 (sold it), that liked Remington Corlokts crimped in the canelure. That said, there is one bullet that I use for my 30-338 that has a canelure but the OACL is such that the canelure is well out from the case mouth. I do not crimp that bullet.

JimmyHoffa may not experience the same SD that I do, but realize that I only neck size fireformed brass, trim by hand and use a case runnout comparator to assist in creating the most concentric and uniform cartridges as possible. The concoctions fired through my rifles are quite refined.  Rifles/bullets/loads are different. Some like that jump to the lands. Some like to build a little pressure early. Some like a slower burn down the barrel. It is the quest of the reloader to find the sweet spot or recipe that works just right.  What works right in one rifle/barrel, may not be the ticket for another.

-Steve

[JimmyHoffa]

Yeah, some guns like different things.  With the exception of measuring run out (lack of tool), it sounds like we prep the cases similarly.  Heck, I even have a process for primer pockets and the flash-hole.  And polishing the inside of the case.  I've been tempted to put something like a Barnes TSX on a mini-lathe or something....just so I can crimp those too!