is crimping necessary for the mini-14 .223?

jambrdly · June 5, 2010, 04:43 PM

Is it actually necessary to crimp .223 bullets for the mini-14? I have been crimping them because I was advised to do so, but lately I've been wondering if it is really necessary or even desirable. The recoil is so mild that I don't how it can actually be setting the bullets back in the case (? yes/no?). On the other hand, I am new to the .223, new to the mini-14 and new to semi-autos so ....

Does crimping affect accuracy one way or the other?

Crosshair · June 5, 2010, 04:51 PM

I put minimal crimp on my .223 and don't have problem with my Mini. YMMV

**Unclenick** · June 5, 2010, 04:53 PM

Yes and no. I never crimp match .223 ammo for my AR, and have had no problems. I just don't want to distort the bullets. Match bullets don't have crimp cannelures, so you have to form them by crimping. Also, I don't use powders that are slow for the load. On the other hand, with some powders, particularly those on the slow side for the bullet weight, it turns out a crimp will increase start pressure just enough to be genuinely helpful to ignition and burn consistency and to improve accuracy over shorter ranges despite a little bullet distortion.

If the gun tends to slam bullet noses into the feed ramp, crimping can help avoid setback. If you are using cast bullets, their lubrication makes them vulnerable to setback, so they must be crimped (though I would only shoot gas checked cast bullets in a gas gun). If the bullets are going to go through extra rough handling, and may be dropped and banged around, crimping can help keep them in place.

steve4102 · June 5, 2010, 11:38 PM

Recoil has little or nothing to do with crimping/neck tension in auto-loaders. It's all about the action and how it affects OAL.

This is what the experts at Sierra have to say about neck tension and auto-loaders. Notice recoil is not mentioned at all.

Neck Tension

When we stop to consider the vigorous (read, downright violent) chambering cycle a loaded round endures in a Service Rifle, it becomes pretty clear it suffers abuse that would never happen in a bolt-action. This is simply the nature of the beast. It needs to be dealt with since there is no way around it.

There are two distinctly different forces that need to be considered: those that force the bullet deeper into the case, and those that pull it out of the case. When the round is stripped from the magazine and launched up the feed ramp, any resistance encountered by the bullet risks having it set back deeper into the case. Due to the abrupt stop the cartridge makes when the shoulder slams to a halt against the chamber, inertia dictates that the bullet will continue to move forward. This is exactly the same principle a kinetic bullet puller operates on, and it works within a chamber as well. Some years ago, we decided to examine this phenomenon more closely. During tests here at Sierra’s range, we chambered a variety of factory Match ammunition in an AR-15 rifle. This ammunition was from one of the most popular brands in use today, loaded with Sierra’s 69 grain MatchKing bullet. To conduct the test, we chambered individual rounds by inserting them into the magazines and manually releasing the bolt. We then repeated the tests by loading two rounds into the magazine, chambering and firing the first, and then extracting and measuring the second round. This eliminated any potential variation caused by the difference between a bolt that had been released from an open position (first round in the magazine) and those subsequent rounds that were chambered by the normal semi-automatic operation of the rifle. Measuring the rounds before chambering and then re-measuring after they were carefully extracted resulted in an average increase of three thousandths (0.003") of forward bullet movement. Some individual rounds showed up to seven thousandths (0.007") movement. Please bear in mind that these results were with factory ammunition, normally having a higher bullet pull than handloaded ammunition.

To counteract this tendency, the semi-auto shooter is left with basically two options: applying a crimp or increasing neck tension.

Link to entire article.
http://www.exteriorballistics.com/re...sgunreload.cfm

Bamashooter · June 6, 2010, 12:27 AM

i think overcrimped affects accuracy. i always do a light crimp with my lee factory crimp die and everything is working fine

June 5, 2010, 04:43 PM	#1
jambrdly Senior Member Join Date: January 31, 2010 Posts: 105	is crimping necessary for the mini-14 .223? Is it actually necessary to crimp .223 bullets for the mini-14? I have been crimping them because I was advised to do so, but lately I've been wondering if it is really necessary or even desirable. The recoil is so mild that I don't how it can actually be setting the bullets back in the case (? yes/no?). On the other hand, I am new to the .223, new to the mini-14 and new to semi-autos so .... Does crimping affect accuracy one way or the other?

June 5, 2010, 04:51 PM	#2
Crosshair Senior Member Join Date: December 16, 2004 Location: Grand Forks, ND Posts: 5,333	I put minimal crimp on my .223 and don't have problem with my Mini. YMMV __________________ I don't carry a gun to go looking for trouble, I carry a gun in case trouble finds me.

June 5, 2010, 04:53 PM	#3
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,060	Yes and no. I never crimp match .223 ammo for my AR, and have had no problems. I just don't want to distort the bullets. Match bullets don't have crimp cannelures, so you have to form them by crimping. Also, I don't use powders that are slow for the load. On the other hand, with some powders, particularly those on the slow side for the bullet weight, it turns out a crimp will increase start pressure just enough to be genuinely helpful to ignition and burn consistency and to improve accuracy over shorter ranges despite a little bullet distortion. If the gun tends to slam bullet noses into the feed ramp, crimping can help avoid setback. If you are using cast bullets, their lubrication makes them vulnerable to setback, so they must be crimped (though I would only shoot gas checked cast bullets in a gas gun). If the bullets are going to go through extra rough handling, and may be dropped and banged around, crimping can help keep them in place. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

June 5, 2010, 11:38 PM	#4
steve4102 Senior Member Join Date: December 23, 2005 Location: Minnesota Posts: 2,952	Recoil has little or nothing to do with crimping/neck tension in auto-loaders. It's all about the action and how it affects OAL. This is what the experts at Sierra have to say about neck tension and auto-loaders. Notice recoil is not mentioned at all. Neck Tension When we stop to consider the vigorous (read, downright violent) chambering cycle a loaded round endures in a Service Rifle, it becomes pretty clear it suffers abuse that would never happen in a bolt-action. This is simply the nature of the beast. It needs to be dealt with since there is no way around it. There are two distinctly different forces that need to be considered: those that force the bullet deeper into the case, and those that pull it out of the case. When the round is stripped from the magazine and launched up the feed ramp, any resistance encountered by the bullet risks having it set back deeper into the case. Due to the abrupt stop the cartridge makes when the shoulder slams to a halt against the chamber, inertia dictates that the bullet will continue to move forward. This is exactly the same principle a kinetic bullet puller operates on, and it works within a chamber as well. Some years ago, we decided to examine this phenomenon more closely. During tests here at Sierra’s range, we chambered a variety of factory Match ammunition in an AR-15 rifle. This ammunition was from one of the most popular brands in use today, loaded with Sierra’s 69 grain MatchKing bullet. To conduct the test, we chambered individual rounds by inserting them into the magazines and manually releasing the bolt. We then repeated the tests by loading two rounds into the magazine, chambering and firing the first, and then extracting and measuring the second round. This eliminated any potential variation caused by the difference between a bolt that had been released from an open position (first round in the magazine) and those subsequent rounds that were chambered by the normal semi-automatic operation of the rifle. Measuring the rounds before chambering and then re-measuring after they were carefully extracted resulted in an average increase of three thousandths (0.003") of forward bullet movement. Some individual rounds showed up to seven thousandths (0.007") movement. Please bear in mind that these results were with factory ammunition, normally having a higher bullet pull than handloaded ammunition. To counteract this tendency, the semi-auto shooter is left with basically two options: applying a crimp or increasing neck tension. Link to entire article. http://www.exteriorballistics.com/re...sgunreload.cfm Last edited by steve4102; June 6, 2010 at 07:32 AM.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

June 6, 2010, 12:27 AM	#5
Bamashooter Senior Member Join Date: March 12, 2010 Posts: 1,860	i think overcrimped affects accuracy. i always do a light crimp with my lee factory crimp die and everything is working fine