Crimping for accuracy

[ma96782]

My $0.02 on the crimp subject.

Too loose.....
The bullet isn't being held "tightly enough" and maybe it will fall off/out/pull away from the case? Then, most times you won't get away with it in a semi-auto.

Too tight......
The bullet could get damaged during the crimping, affecting accuracy. Maybe, you could even create a dangerous increase in the pressure curve?

Just Rrrrrright......
Perhaps.....you'll experience "Happiness" (to a point).

LOL.....THAT, sounds like the story of the 3 bears.
But then, how much is too much or too little?

Aloha, Mark

PS.......depending on the situation.......some people swear on the usage of a FCD and some people swear at the FCD.

 

[Local Loader]

My $0.02 on the crimp subject.

Too loose.....
The bullet isn't being held "tightly enough" and maybe it will fall off/out/pull away from the case? Then, most times you won't get away with it in a semi-auto.

Too tight......
The bullet could get damaged during the crimping, affecting accuracy. Maybe, you could even create a dangerous increase in the pressure curve?

Just Rrrrrright......
Perhaps.....you'll experience "Happiness" (to a point).

LOL.....THAT, sounds like the story of the 3 bears.
But then, how much is too much or too little?

Aloha, Mark

PS.......depending on the situation.......some people swear on the usage of a FCD and some people swear at the FCD.

I've used roll crimps, FCD and no crimp for my for my 223/5.56 and haven't seen much difference at all other than a tiny bit more recoil with an FCD.

 

[MymuttBear]

Oh, we jumped to handgun loads. Well, that is a different scenario.
In some cases, such as using 2400 in a 44 mag with heavy bullets in revolver, a crimp is desired. But the reasons are to help build pressure (consistency) and keep the bullets from moving forward during recoil and locking up the cylinder.

In summary, no one size fits all.

"Oh, we jumped to handgun loads".
Yep but I have also started to crimp rifle loads as well. Guess I was so happy with the results I got with handgun loads I figured it couldn't hurt to go all in on my rifle loads as well. A bench rest shooter I am not

 

[orygun]

Oh, we jumped to handgun loads.

Yeah, in post #7...

That's not what the OP was talking about, but we have a tendency to "thread drift" around here.

 

[NobullSKS]

Question….

I'd like to try a lite crimp.308 in my AR10. I don't have a crimp die but thought removing the de primer from sizing….. and a soft touch to crimp.

The initial forum reading….. it's not a good plan because sizer neck diameter is far below sammi spec. Makes sense but I can stop by feel and not full send into sizer, right?

If I still feel like crimping on next run I'll buy a crimp …. I just have.308 on my bench now.

 

[orygun]

Question….

I'd like to try a lite crimp.308 in my AR10. I don't have a crimp die but thought removing the de primer from sizing….. and a soft touch to crimp.

The initial forum reading….. it's not a good plan because sizer neck diameter is far below sammi spec. Makes sense but I can stop by feel and not full send into sizer, right?

If I still feel like crimping on next run I'll buy a crimp …. I just have.308 on my bench now.

Most bullet seating dies will provide a little crimp. I would back the bullet seater out and use that die instead of the sizing die.

 

[NobullSKS]

Most bullet seating dies will provide a little crimp. I would back the bullet seater out and use that die instead of the sizing die.

Great…. I give it a shot. Thank you

 

[Koda]

My conclusion is that crimping for accuracy can be done, but not a popular option as there are other ways to tune precision. I suspect its becoming popular with Hammer loaders because I read that Hammers are not sensitive to seating depth.

I think what I will do is continue my load dev without crimping, find the velocity I want and then see what my group size is, no sense adding a step if I'm 1moa or less. If its not 1moa I might try backing up a full grain and doing a crimp ladder, starting with a very light crimp and work up with 1/8 turns. If I go down the crimp rabbithole, I'll share what I find here.

 

[Certaindeaf]

My very first handloads were for my Browning Hi-Power using the Lee Loader. You had to hammer crimp them to remove the hammered flare so I crimped the hell out of them with what would be most properly described as a severe roll crimp.
They shot just fine.

 

[orygun]

My very first handloads were for my Browning Hi-Power using the Lee Loader. You had to hammer crimp them to remove the hammered flare so I crimped the hell out of them with what would be most properly described as a severe roll crimp.
They shot just fine.

I do that with any revolver round. I don't crimp rounds that headspace on the mouth very much, but I always turn them in a little. The only rounds I ever had an issue with in 45 ACP are ones with bulged cases from oversize cast bullets that had a hard time chambering.
I reload handgun cartridges for reliability, not so much accuracy.

 

[Koda]

Loaded up some more today for my next range session, all uncrimped but I crimped 2 rounds just to compare the velocities I got last time with the same charge weight.
The Lee FCD is super easy to use, my first time. I lost my zero starting point but think I can just put an ink mark next time and repeat the same starting point.

Not saying Im gonna start crimping my rifle rounds. Im just doing this small sample to learn and see how it affects the velocity (pressure).

The drive bands on the Hammer bullets seem perfect for crimping into.
This is a light 1/4 turn crimp (right). I do think it should be easy to control consistency if I went down this road.
280AI, 140g Absolute Hammer.

 

[Certaindeaf]

I do that with any revolver round. I don't crimp rounds that headspace on the mouth very much, but I always turn them in a little. The only rounds I ever had an issue with in 45 ACP are ones with bulged cases from oversize cast bullets that had a hard time chambering.
I reload handgun cartridges for reliability, not so much accuracy.

Yes, I understand. Those loads were anything but consistent in crimp because you'd just eyeball it and ranged from just barely to ridiculous they still were very accurate.

 

[orygun]

Loaded up some more today for my next range session, all uncrimped but I crimped 2 rounds just to compare the velocities I got last time with the same charge weight.
The Lee FCD is super easy to use, my first time. I lost my zero starting point but think I can just put an ink mark next time and repeat the same starting point.

Not saying Im gonna start crimping my rifle rounds. Im just doing this small sample to learn and see how it affects the velocity (pressure).

The drive bands on the Hammer bullets seem perfect for crimping into.
This is a light 1/4 turn crimp (right). I do think it should be easy to control consistency if I went down this road.
280AI, 140g Absolute Hammer.

View attachment 1346211

Nice. Certainly worth a try. Like I know what I'm talking about, but if you have a groove to crimp into, with trimmed, equal length cases, couldn't this actually lead to consistency?

 

[Koda]

Nice. Certainly worth a try. Like I know what I'm talking about, but if you have a groove to crimp into, with trimmed, equal length cases, couldn't this actually lead to consistency?

Yes, but my question is how easy or hard it will be to consistently get the same squeeze from the crimp die. I lost my "zero" point but the Lee FCD was so simple to use I think I could get it exact the same once I mark where to start from.

 

[orygun]

I think if any sizing die is adjusted to be correct when the ram is at the extent of it's travel, assuming similar length cases, it could be consistent. Whether or not is helps is a completely different subject.

 

[Koda]

The lock ring on the Lee Crimp die has an oring on the bottom, so it had some give to where to set the height at. The crimping part of the die moves when it touches the shell holder, so it was hard to determine where I was starting from. I think I can figure it out if I need to though.

 

[orygun]

Good luck!