Crimp or not to crimp

[Uncle Norm]

I crimp .22 Hornet, .243 Win and .260 Rem. Benefits are cleaner burn with N160, smaller groups, slightly higher muzzle velocity and reduced extreme spread of muzzle velocity. Nothing dramatic but I think it worth the extra effort.

 

[Klenchblaize]

Crimp the wee ones such as 22 Hornet as it affords the consistent and significant degree of neck tension that is otherwise a real challenge to obtain with conventional case sizing, including the use of a well chosen neck bushing die.

I have Muir to thank for this guidance, notwithstanding it took a while to get over my poorly informed prejudice that for the most part can be traced to excessive working of the neck.

K

 

[nun_hunter]

Unless you have a custom chamber neck turning is a waste of time I would suggest as it will do nothing. Measuring case neck thickness, sorting brass by weight etc etc are a waste of time. May be of some value in benchrest, dunno it's not my game. In other contexts PRS, Stalking etc, the pros will tell you that you are wasting time and effort. Neck sizing went out with the arc.

Crimping does not replicate any of the processes name checked above.

Crimping can (most likely does) help keep neck tension consistent and therefore help with more consistent initial pressures and accuracy.

The bits I mentioned also do the same things just in a more precise manner and could lead to greater benefits if everything else in your reloading and rifle are also as precise.

 

[kenbro]

I crimp mine.
I want anything to aid a good ignition.

Bet ya don’t get bullets left in the barrel and powder in the action…
Ken.

 

[LeftHandGuy]

I crimp mine.
I want anything to aid a good ignition.

So, apologies to @Floralys for this partial hijack, but I have never considered that crimping may aid ignition, could you expand on that a little bit @Smellydog?

 

[Smellydog]

So, apologies to @Floralys for this partial hijack, but I have never considered that crimping may aid ignition, could you expand on that a little bit @Smellydog?

Some cartridge/powder type/bullet combinations need some resistance in order to achieve reliable ignition. Usually some ball type or spherical powders. Often a magnum primer is also recommended.

A classic example of problematic ignition today is the wee 17 HMR. It suffers from work hardened brass splitting at the neck in storage. Often wrongly quoted as allowing damp to compromise the powder it's actually causing a total flame out or a partial flame out and then reignition. Because there was no resistance to move from the bullet insuring thorough ignition.
Unfortunately, re ignition occurs once the bullet has entered the bore and stopped, or nearly stopped and becoming an obstruction.
That's how you here of damaged rifles chambered in HMR.
Exactly the same thing can and has happened to centre fires.

Usually it doesn't happen with extruded powders or black powder.

 

[Greenmist]

Simple way to find out, do a batch of crimped rounds and a batch of uncrimped, then compare the results, most of my rifles I don't , two I do

 

[JTO]

Getting consistancy with a 'light crimp' could be difficult, perhaps.

 

[Len the dog]

Does crimping reduce the life of the brass as it is another step in working it. Obviously if it does then annealing will rectify this but I'm asking about non-annealed life expectancy.

 

[VIGILAIRE]

+ 1 for Lee factory crimp die (FCD) .223 through to .416.

 

[tim@tcs]

Essentially this is all about neck tension and consistency. If your brass is good enough it shouldnt matter but if you find inconsistencies in results then using a crimp would be beneficial. All things considered there are a list of things that affect consistency and the biggest one is the person shooting.

 

[LeftHandGuy]

Some cartridge/powder type/bullet combinations need some resistance in order to achieve reliable ignition. Usually some ball type or spherical powders. Often a magnum primer is also recommended.

A classic example of problematic ignition today is the wee 17 HMR. It suffers from work hardened brass splitting at the neck in storage. Often wrongly quoted as allowing damp to compromise the powder it's actually causing a total flame out or a partial flame out and then reignition. Because there was no resistance to move from the bullet insuring thorough ignition.
Unfortunately, re ignition occurs once the bullet has entered the bore and stopped, or nearly stopped and becoming an obstruction.
That's how you here of damaged rifles chambered in HMR.
Exactly the same thing can and has happened to centre fires.

Usually it doesn't happen with extruded powders or black powder.

Well, that's me doubling down on my support for crimping! Thanks again @Smellydog

 

[Floralys]

Thank you everyone for your input! I guess I will try both crimped and not crimped ammo to see if there would be big difference in grouping.

 

[Smellydog]

Thank you everyone for your input! I guess I will try both crimped and not crimped ammo to see if there would be big difference in grouping.

There won't be a big difference.

 

[trickie]

I don’t crimp, tried it on my 6.5 Creedmoor, no improvement in groups, fps was up about 30 fps, SD slightly worse.
If I had a semi auto 223 rifle I most certainly would or any other rifle calibre centre fire. I don’t own an underlever

 

[tim@tcs]

I don’t crimp, tried it on my 6.5 Creedmoor, no improvement in groups, fps was up about 30 fps, SD slightly worse.
If I had a semi auto 223 rifle I most certainly would or any other rifle calibre centre fire. I don’t own an underlever

To be honest tension on straight walled cases can be enough to hold, plenty of other cartridges for under levers like 30/30 and lead bullets work well in underlevers as revolvers. Not every under lever has a tube magazine and plenty are available for rimless FMJ or Sp projectiles!
Recoil is rarely savage enough to shift the bullet seated in a case!

 

[Wink]

I light crimp my .22 Hornet and get key holes at 100m with Sierra SP, die it set in my turret press so takes no time.

 

[Muir]

I crimp everything and do not condider load development complete until it is crimped. Whether it effects accuracy depends in other factors in the load chain: a poor load won't be cured by crimping. A good load will, at worst, remain unchanged. I had this discussion last night where one very experienced reloader discribed his first crimping experiene wth his M1A Super Match 308 many decades back. Went from 1.2 MOA to one ragged hole. Like myself, the Lee FCD is all he uses. If Lee doesn't make one, I have them make it custom. ~Muir

 

[Foxyboy43]

I crimp everything and do not condider load development complete until it is crimped. Whether it effects accuracy depends in other factors in the load chain: a poor load won't be cured by crimping. A good load will, at worst, remain unchanged. I had this discussion last night where one very experienced reloader discribed his first crimping experiene wth his M1A Super Match 308 many decades back. Went from 1.2 MOA to one ragged hole. Like myself, the Lee FCD is all he uses. If Lee doesn't make one, I have them make it custom. ~Muir

A very happy return to SD fella - just in time not to win the Supporters Draw…..

 

[Smellydog]

I crimp everything and do not condider load development complete until it is crimped. Whether it effects accuracy depends in other factors in the load chain: a poor load won't be cured by crimping. A good load will, at worst, remain unchanged. I had this discussion last night where one very experienced reloader discribed his first crimping experiene wth his M1A Super Match 308 many decades back. Went from 1.2 MOA to one ragged hole. Like myself, the Lee FCD is all he uses. If Lee doesn't make one, I have them make it custom. ~Muir

Good to hear from you buddy