Bullet seating versus crimping... - The Firearms Forum

1911Man · 01-28-2010, 08:42 AM

I'm still in the reading/researching/asking stage of reloading. I will be reloading .45ACP and am wondering what "crimping" is. Then, what is "roll crimping" and what calibers is that for? Do I have to "crimp" .45ACP? Is "crimping" different than what my bullet seating die does? Please outline, in detail, the scope of "crimping," "bullet seating," and whatever else about these I need to know.

Thanks a bunch, folks.

carver · 01-28-2010, 08:56 AM

Quote:

Originally Posted by 1911Man

I'm still in the reading/researching/asking stage of reloading. I will be reloading .45ACP and am wondering what "crimping" is. Then, what is "roll crimping" and what calibers is that for? Do I have to "crimp" .45ACP? Is "crimping" different than what my bullet seating die does? Please outline, in detail, the scope of "crimping," "bullet seating," and whatever else about these I need to know.

Thanks a bunch, folks.

If you are reading your reloading manual this is covered in it. Sometimes ya need a crimp! Sometimes ya don't! All most anything you can think of will be covered in your reloading manual. Read it, then read it again, it ain't that much to learn.

army mp · 01-28-2010, 09:03 AM

Crimping is done with your seating die. And yes I would put a crimp on 45ACP rounds. What most guys do is. Put a case in the shell holder. Move the ram to the top. Now back off the seater stem. Screw the die in till it comes in contact with the casing. Now you can start a bullet into the case and adjust. OAL.( over All length ) once you have proper. OAL Back the seater stem out about a turn . Now screw the die in about a ¼ to ½ turn. This should crimp the bullet. Check your OAL again. If correct, screw the seater stem down on the round in your press and you should be ready to load.

techoca · 01-28-2010, 09:20 AM

1911Man,
The .45ACP uses a taper crimp; you need to make sure your die has a taper crimp and not a roll crimp. It probably does, but make sure. I seat my bullets with no crimp being done by the seating die (read the die instructions), then I taper crimp as a separate process using a Redding taper crimp die for .45ACP. Most of your hardcore .45ACP shooters or shooters with match barrels will do it this way. Many will argue that this is not necessary and it may not be for their uses, it is for mine.

I will warn you of a potential problem if you use Lee Carbide dies for .45ACP. The Lee die only sizes the case to 1/8" from the bottom of the case, leaving the case too fat on the bottom and this will cause failure to return to battery issues on some guns with match grade or tightly toleranced barrels. Ask me how I know.

Regards

1911Man · 01-28-2010, 09:21 AM

I've purchased RCBS carbides. I should be good, eh?

techoca · 01-28-2010, 10:01 AM

Quote:

Originally Posted by 1911Man

I've purchased RCBS carbides. I should be good, eh?

Excellent choice 1911Man.

Good luck with your .45ACP reloading, it is my favorite handgun cartridge to shoot and hand load. I load 200gr. Dardas LSWC over 5.0gr. Red Dot powder for range ammo and it shoots beautifully out of a 1911, very accurate load.

army mp · 01-28-2010, 10:04 AM

Yes and if new Dies there should be directions with the Dies. But if you read your reloading Manual and ask lots of questions and be safe. You will be loading Ammo in no time.

LDBennett · 01-28-2010, 10:27 AM

Here is the way the process works for pistol cartridges:

The sizing die sizes the entire case down to a dimension that assures normal size bullets are an interference fit into the case (by a couple of thousands of an inch).

The belling die bells the mouth of the case so that the bullet will just barely start into the case about 1/16 inch of so.

The seating die pushes the bullet into the case to the right depth. The fit in most pistol cartridges can be so tight that the imprint of the base of the bullet can be seen through the case wall. This lets the bell, put on the case by the belling die, stand out from the case body and the cartridge MAY not fit into the chamber of the gun so there must be a process to push the bell back into the case.

The body of the seating die can be adjusted to remove the bell or to crimp the case throat into the bullet. That allows the bell to be removed and the bullet to be semi locked into the case.

If it is an auto-loading cartridge like 9mm, 10mm, 40 S&W, or 45ACP (there are others too) the crimp is a taper profile. If it is a revolver cartridge the crimp is a rolled over edge usually into a grove or cannelure in the bullet body. Never uses a roll crimp on a cartridge that head spaces on the mouth of the case (like virtually all semi-auto calibers... see list above).

When any crimp is applied it is important that the diameter of the cartridge at the crimp not exceed the dimensions given in the reloading manuals.

LDBennett

mikld · 01-28-2010, 10:57 AM

No offence intended...

But, first and foremost; you need a copy of ABCs of Reloading, or Lyman's 49th Edition Reloading Manual, or Lee Modern Reloading. Then get the other two. All the info you need to get started is in these three manuals. Read them and with that info you'll be able to buy the reloading equipment suited to your reloading needs. You'll get a lot of good info here too, but with a good manual (not just a recipe book) you'll have the info at hand in front of you. I been stuffin' brass for 35 yrs. off and on (lots of off) and still keep my manuals handy.

312shooter · 01-28-2010, 04:53 PM

Quote:

Originally Posted by mikld

No offence intended...

But, first and foremost; you need a copy of ABCs of Reloading, or Lyman's 49th Edition Reloading Manual, or Lee Modern Reloading. Then get the other two. All the info you need to get started is in these three manuals. Read them and with that info you'll be able to buy the reloading equipment suited to your reloading needs. You'll get a lot of good info here too, but with a good manual (not just a recipe book) you'll have the info at hand in front of you. I been stuffin' brass for 35 yrs. off and on (lots of off) and still keep my manuals handy.

+1, Lymans 49th is a great read if you are into shooting, I guarentee you will be excited and well informed after this manual.

bluesea112 · 01-29-2010, 10:02 AM

The term "crimping" means pushing the mouth of the case in tight around the bullet after the bullet is seated in the case. Roll crimping actually rolls the edge of the case inward so that the edge of the case "bites" into the bullet. Taper crimping tightens the case against the bullet, but it does not bite into the bullet.
From my experience, roll crimping increases pressure more than taper crimping when the cartridge is fired.
Lee factory crimp is a type of taper crimping, and it is my favorite.
I don't like roll crimping, because it is too easy to bulge the cartridge case (in my opinion)

01-28-2010, 08:42 AM	#1
1911Man Member Join Date: Jan 2010 Location: St. Louis Posts: 39	Bullet seating versus crimping... I'm still in the reading/researching/asking stage of reloading. I will be reloading .45ACP and am wondering what "crimping" is. Then, what is "roll crimping" and what calibers is that for? Do I have to "crimp" .45ACP? Is "crimping" different than what my bullet seating die does? Please outline, in detail, the scope of "crimping," "bullet seating," and whatever else about these I need to know. Thanks a bunch, folks. __________________ Liberals suck. -->

01-28-2010, 09:03 AM	#3
army mp V.I.P. Member Join Date: Jan 2009 Location: western Pa, Posts: 479	Re: Bullet seating versus crimping... Crimping is done with your seating die. And yes I would put a crimp on 45ACP rounds. What most guys do is. Put a case in the shell holder. Move the ram to the top. Now back off the seater stem. Screw the die in till it comes in contact with the casing. Now you can start a bullet into the case and adjust. OAL.( over All length ) once you have proper. OAL Back the seater stem out about a turn . Now screw the die in about a ¼ to ½ turn. This should crimp the bullet. Check your OAL again. If correct, screw the seater stem down on the round in your press and you should be ready to load.

01-28-2010, 09:20 AM	#4
techoca V.I.P. Member Join Date: Nov 2008 Posts: 329	Re: Bullet seating versus crimping... 1911Man, The .45ACP uses a taper crimp; you need to make sure your die has a taper crimp and not a roll crimp. It probably does, but make sure. I seat my bullets with no crimp being done by the seating die (read the die instructions), then I taper crimp as a separate process using a Redding taper crimp die for .45ACP. Most of your hardcore .45ACP shooters or shooters with match barrels will do it this way. Many will argue that this is not necessary and it may not be for their uses, it is for mine. I will warn you of a potential problem if you use Lee Carbide dies for .45ACP. The Lee die only sizes the case to 1/8" from the bottom of the case, leaving the case too fat on the bottom and this will cause failure to return to battery issues on some guns with match grade or tightly toleranced barrels. Ask me how I know. Regards __________________ techoca "The purpose of the pistol is to stop a fight that somebody else has started, almost always at very short range." Col. Jeff Cooper

01-28-2010, 09:21 AM	#5
1911Man Member Join Date: Jan 2010 Location: St. Louis Posts: 39	Re: Bullet seating versus crimping... I've purchased RCBS carbides. I should be good, eh? __________________ Liberals suck.

01-28-2010, 10:04 AM	#7
army mp V.I.P. Member Join Date: Jan 2009 Location: western Pa, Posts: 479	Re: Bullet seating versus crimping... Yes and if new Dies there should be directions with the Dies. But if you read your reloading Manual and ask lots of questions and be safe. You will be loading Ammo in no time.

01-28-2010, 10:27 AM	#8
LDBennett Advanced Senior Member Join Date: Dec 2003 Location: Hesperia, CA Posts: 5,754	Re: Bullet seating versus crimping... Here is the way the process works for pistol cartridges: The sizing die sizes the entire case down to a dimension that assures normal size bullets are an interference fit into the case (by a couple of thousands of an inch). The belling die bells the mouth of the case so that the bullet will just barely start into the case about 1/16 inch of so. The seating die pushes the bullet into the case to the right depth. The fit in most pistol cartridges can be so tight that the imprint of the base of the bullet can be seen through the case wall. This lets the bell, put on the case by the belling die, stand out from the case body and the cartridge MAY not fit into the chamber of the gun so there must be a process to push the bell back into the case. The body of the seating die can be adjusted to remove the bell or to crimp the case throat into the bullet. That allows the bell to be removed and the bullet to be semi locked into the case. If it is an auto-loading cartridge like 9mm, 10mm, 40 S&W, or 45ACP (there are others too) the crimp is a taper profile. If it is a revolver cartridge the crimp is a rolled over edge usually into a grove or cannelure in the bullet body. Never uses a roll crimp on a cartridge that head spaces on the mouth of the case (like virtually all semi-auto calibers... see list above). When any crimp is applied it is important that the diameter of the cartridge at the crimp not exceed the dimensions given in the reloading manuals. LDBennett Last edited by LDBennett; 01-29-2010 at 05:19 AM..

01-28-2010, 10:57 AM	#9
mikld Senior Member Join Date: Jun 2009 Location: Oregon Posts: 577	Re: Bullet seating versus crimping... No offence intended... But, first and foremost; you need a copy of ABCs of Reloading, or Lyman's 49th Edition Reloading Manual, or Lee Modern Reloading. Then get the other two. All the info you need to get started is in these three manuals. Read them and with that info you'll be able to buy the reloading equipment suited to your reloading needs. You'll get a lot of good info here too, but with a good manual (not just a recipe book) you'll have the info at hand in front of you. I been stuffin' brass for 35 yrs. off and on (lots of off) and still keep my manuals handy. __________________ My Anchor is holding fast. Last edited by mikld; 01-28-2010 at 10:58 AM..

01-29-2010, 10:02 AM	#11
bluesea112 Advanced Senior Member Join Date: Nov 2005 Location: West, TX Contributor Posts: 1,262	Re: Bullet seating versus crimping... The term "crimping" means pushing the mouth of the case in tight around the bullet after the bullet is seated in the case. Roll crimping actually rolls the edge of the case inward so that the edge of the case "bites" into the bullet. Taper crimping tightens the case against the bullet, but it does not bite into the bullet. From my experience, roll crimping increases pressure more than taper crimping when the cartridge is fired. Lee factory crimp is a type of taper crimping, and it is my favorite. I don't like roll crimping, because it is too easy to bulge the cartridge case (in my opinion) Last edited by bluesea112; 01-29-2010 at 10:03 AM..