When to crimp?

[timthetoolman]

I know this is pandora's box of opinions, but I'd like to hear what everyone else is doing.  I typically crimp rounds for semi automatic and lever action (tube mag) , but I dont for single shot or bolt action.  For pistol I have started crimping my 44 mags loads as it helps with reducing the unburnt powder and increases consistency.  I also crimp my 38 wad cutter loads. The rest just have a light crimp to hold everything in place while firing and I get great results from my 9, 40, and 45 that way.

 

It seems everyone I ask or every place I read give a different version of when to crimp.  Help me clear this up will ya?

[mikegideon]

I can't think of any reason not to. I crimp everything with Lee FCD's except .458 SOCOM. The .458 is a custom die, and I'll eventually have one. Setback us ugly, no matter where you find it.. 

[Static_USMC]

I crimp everything except match bolt gun loads. Lots of variables though from heavy crimp on tracers to very light taper crimp on frangible 9 mm loads

[TNMTBik3r]

I've thought about getting Lee FCDs for my pistols but haven't yet. I use Hornady and RCBS dies and use the built-in crimp - followed the instructions to set the dies. It seems to be close to the crimp on some factory rounds I compared to.

[mikegideon]

I've thought about getting Lee FCDs for my pistols but haven't yet. I use Hornady and RCBS dies and use the built-in crimp - followed the instructions to set the dies. It seems to be close to the crimp on some factory rounds I compared to.

 

The Lee is the best. It does require another stroke on the press if you're not using a progressive. It's just lots gentler on the brass than the roll crimp in the seating dies

[Dolomite_supafly]

I do not crimp anything except SHTF ammo and realistically there was no reason to. I do not crimp my semi auto rounds, rifle or pistol, or rounds for my bolt guns. Personally I think using neck tension is a better option because it doesn't deform the bullet like a crimp can sometimes do. I use a neck sizer and a body sizer as seperate dies. I take .002" off the neck sizing mandrel to provide more neck tension. With pistol rounds I only remove the bell. My 300 Blackout loads, jacketed as well as cast, do not get crimped at all either.

 

BTW, my crimped SHTF ammo had the smallest SD I have ever had. Not sure if it was the crimp, the powder I have never tried before or the primers but the stars aligned perfectly to produce the numbers.

[mikegideon]

 

 

BTW, my crimped SHTF ammo had the smallest SD I have ever had. Not sure if it was the crimp, the powder I have never tried before or the primers but the stars aligned perfectly to produce the numbers.

 

That's because the crimp (as you know) helps to normalize the shot start pressure. Lots of folks get improved accuracy with a crimp. 

[Dolomite_supafly]

My best groups have always been with uncrimped rounds.

[gregintenn]

I usually crimp if the bullet has a cannelure or crimp groove. For semi auto pistol rounds, I crimp enough to remove the bell I put into the case mouth to aid in bullet seating.

 

Short of that, I never crimp.

[Guest tnpaul]

I know this is pandora's box of opinions, but I'd like to hear what everyone else is doing.  I typically crimp rounds for semi automatic and lever action (tube mag) , but I dont for single shot or bolt action.  For pistol I have started crimping my 44 mags loads as it helps with reducing the unburnt powder and increases consistency.  I also crimp my 38 wad cutter loads. The rest just have a light crimp to hold everything in place while firing and I get great results from my 9, 40, and 45 that way.

 

It seems everyone I ask or every place I read give a different version of when to crimp.  Help me clear this up will ya?

I pretty much do like you

[timthetoolman]

I have had bullets move around in my revolvers to the point of not being able to rotate the cylinder.  So now I crimp, like said earlier, for them.  In my semis I have never had an issue but I load a bunch at once and feel like (a guess) it stores better long term, without a chance of getting disturbed.  I have definitely gotten better groups out of my bolt guns by fireforming and then using a neck sizer with no crimp during loading. 

 

I use a Dillon progressive for most loading, but for my more precise stuff I use my rock chucker.  Seems like the answer lies in trying both in a particular gun and load to see what performs best.