Crimping?????????

Mountainman6 · August 28, 2015, 09:36 PM

Ok first off I don't crimp any of my bolt action rifle loads! But I'm now loading for my ar15 and I had a couple of bullets get set back in the case while chambering on some test loads! So my question is in the reloading data do they compensate for the possible use of a crimp in the min-max load data?

Mobuck · August 28, 2015, 09:46 PM

I crimp ALL my loads for the AR. I think the variation is slight and would be taken into account as you work your loads up. Crimping bullets is not automatically bad.

Longshot4 · August 28, 2015, 09:46 PM

I rarely will go to max load. After all for what? I would simply back off three or four grains and start to work them up from there with your crimp. Now this is where I ask do your bullets have a crimping grove? I would want a grove to crimp on.

Mountainman6 · August 28, 2015, 09:56 PM

I use a lee factory crimp die and have only crimped very lightly just enough to lay the case mouth down on the cannelure of the bullet so there isn't a ridge on the case mouth

Ifishsum · August 28, 2015, 10:35 PM

I'd say either you're not getting enough neck tension or your rifle is not feeding as it should (or both). Neither of my ARs set back bullets upon feeding, and in my experience if one does, even a crimp won't necessarily stop it.

In answer to your question, a proper crimp should not make a significant difference in pressure so I'd say no.

5whiskey · August 28, 2015, 10:47 PM

My PC response is "if you change a variable, start at 10% of max and work your way up."

My real world experience response is crimping has ALMOST no measurable effect on pressure unless you act a fool with it and actually deform the projectile. Of course I don't burn the barn doors down with any of reloads unless I'm going to be shooting 500+ yards or I'm loading .357. My semi-auto pistol and AR loads are mild.

At any rate, to the OP, I put a pretty firm crimp on AR .223 rounds because I'm afraid of set back during chambering. Reloading data isn't separated by crimp/no crimp because it honestly doesn't make a difference. I will say, however, that the standard advice is to start at 10% max load and work up. No real reason to want max load AR plinking rounds anyway. Work it up until you hit the accuracy sweet spot and roll on with it.

August 28, 2015, 09:36 PM	#1
Mountainman6 Junior Member Join Date: August 30, 2013 Location: Pinson, Alabama Posts: 14	Crimping????????? Ok first off I don't crimp any of my bolt action rifle loads! But I'm now loading for my ar15 and I had a couple of bullets get set back in the case while chambering on some test loads! So my question is in the reloading data do they compensate for the possible use of a crimp in the min-max load data?

August 28, 2015, 09:46 PM	#2
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	I crimp ALL my loads for the AR. I think the variation is slight and would be taken into account as you work your loads up. Crimping bullets is not automatically bad.

August 28, 2015, 09:46 PM	#3
Longshot4 Senior Member Join Date: February 23, 2014 Posts: 868	I rarely will go to max load. After all for what? I would simply back off three or four grains and start to work them up from there with your crimp. Now this is where I ask do your bullets have a crimping grove? I would want a grove to crimp on.

August 28, 2015, 09:56 PM	#4
Mountainman6 Junior Member Join Date: August 30, 2013 Location: Pinson, Alabama Posts: 14	I use a lee factory crimp die and have only crimped very lightly just enough to lay the case mouth down on the cannelure of the bullet so there isn't a ridge on the case mouth

August 28, 2015, 10:35 PM	#5
Ifishsum Senior Member Join Date: September 15, 2005 Location: Oregon Posts: 1,035	I'd say either you're not getting enough neck tension or your rifle is not feeding as it should (or both). Neither of my ARs set back bullets upon feeding, and in my experience if one does, even a crimp won't necessarily stop it. In answer to your question, a proper crimp should not make a significant difference in pressure so I'd say no.

August 28, 2015, 10:47 PM	#6
5whiskey Senior Member Join Date: October 23, 2005 Location: US Posts: 3,753	My PC response is "if you change a variable, start at 10% of max and work your way up." My real world experience response is crimping has ALMOST no measurable effect on pressure unless you act a fool with it and actually deform the projectile. Of course I don't burn the barn doors down with any of reloads unless I'm going to be shooting 500+ yards or I'm loading .357. My semi-auto pistol and AR loads are mild. At any rate, to the OP, I put a pretty firm crimp on AR .223 rounds because I'm afraid of set back during chambering. Reloading data isn't separated by crimp/no crimp because it honestly doesn't make a difference. I will say, however, that the standard advice is to start at 10% max load and work up. No real reason to want max load AR plinking rounds anyway. Work it up until you hit the accuracy sweet spot and roll on with it.