Crimping a non-cannelured bullet

[sprint]

The idea seems contrary to common sense.

The cannelure exists to provide a latitudinal recess for crimping the round without deforming the projectile, yes?

Upon testing by providing a light crimp and then pulling, it occurred to me that every such attempt resulted in deformation of the projectile.

Yet, I have heard others, who know more about reloading than I, vehemently state that the benefits outweigh the cost when feeding into a semi-auto.

What are your thoughts on this?

 

[OneBarfly]

There are two main reason to use a crimp. One is to prevent a bullet from moving or seating further in the cartridge when bouncing around in a magazine while firing. The second being uniformity of ignition by holding each bullet tightly in one consistant position. As you pointed out, crimping (with or without a cannelure) will likely create some bullet distortion; however one must weight the positive against the negatives. I never crimp my bolt action rounds as I have never experience bullet set-back and feel that the bullet is being held tightly enough for uniform ignition. I do however chose to crimp my semi-autos cartridges.

 

[SandRoad]

For many people reading this thread, there is a difference between crimping of handgun and rifle cartridges.

Most semi auto HANDGUN cartridges headspace on the case mouth. If you crimp too much, the cartridge will slide past the chamber and into the throat of the barrel, potentially creating very high pressures when fired. Also, if the cartridge moves forward, it will be away from the breech face, and away from the firing pin, causing misfires.

That is why there are taper crimp dies for most semi auto handgun calibres. They leave the front edge of the case mouth exposed for proper headspacing. The taper crimp die will tend to "squeeze" the bullet a bit, creating a ridge which will keep the bullet from being set back, along with the tension of the taper crimp.

For rifle cartridges, you can crimp, but it will decrease accuracy. If you are worried about bullet setback, then put a dab of lacquer on the bullet which will "glue" it to the case. Consistent neck tension is very important for accuracy.

Or you can get your own cannalure tool to put it where ever you want.

http://www.bulletswage.com/hct-1.htm

 

[BC_Guy]

I've played around with this a bit for rifles. You can try the lee crimp die, which lets you dial on a little bit of crimp and touts itself as being 'even for bullets without cannelure'. Didn't care for it, mainly because I found a better way...

Another thing you can try (I got the idea from the Sierra reloading manual, it has a whole section on reloading for semi auto rifle) is to use a neck bushing die for sizing and select a tighter than normal bushing for the neck. It sizes the body normally but allows you to vary the neck tension.
This allows you to skip crimping while still increasing neck tension (thus achieving the same end result). I got a redding die with a bunch of bushings and experimented, both with stripping the same round off a mag over and over and checking for a change in oal (ar15) to see if there was enough tension, and also to see if it made any difference either way on the target. Works like a charm, saves me a step, and means I don't have to chew in on the sides of my non-cannelured bullets. I could check and see what size bushing I ended up with if you were going to go that route.

 

[carbonrod]

Any seating in tight neck will deform the projectile. I played around using SMK tips in 308, and 223, neck turned, normal, and crimped lightly. All deform the tip if you look at it in a 10x, though the uncrimped ones were more light scratches. The crimped rounds, though you could see a grouve in them, still shoot well.

In the end, I lightly crimp on my semi(service rifle), and hunting rounds. I find that the resulting rounds are still way more accurate them I am in positional shooting, so it is a nice comfort thing to have on my loads with little time overhead associated with them.

 

[johnnyreb65]

For many people reading this thread, there is a difference between crimping of handgun and rifle cartridges.

Most semi auto HANDGUN cartridges headspace on the case mouth. If you crimp too much, the cartridge will slide past the chamber and into the throat of the barrel, potentially creating very high pressures when fired. Also, if the cartridge moves forward, it will be away from the breech face, and away from the firing pin, causing misfires.

That is why there are taper crimp dies for most semi auto handgun calibres. They leave the front edge of the case mouth exposed for proper headspacing. The taper crimp die will tend to "squeeze" the bullet a bit, creating a ridge which will keep the bullet from being set back, along with the tension of the taper crimp.

For rifle cartridges, you can crimp, but it will decrease accuracy. If you are worried about bullet setback, then put a dab of lacquer on the bullet which will "glue" it to the case. Consistent neck tension is very important for accuracy.

Or you can get your own cannalure tool to put it where ever you want.

http://www.bulletswage.com/hct-1.htm

I'm new to reloading so this can be cinfusing..I have a Lee factory Crimp Die, are these taper dies?

Also

I was given a booklet on reloading and in it this statement is made, regarding pistol crimping and headspace.

Carroll Pilant of Sierra Bulltets says, " With most autoloading guns the cartridge headspace is actually set by the extractor holding the case head against the bolt face.So case mouth diameter is really no that important"

So who's right?

 

[G37]

I'm new to reloading so this can be cinfusing..I have a Lee factory Crimp Die, are these taper dies?

Also

I was given a booklet on reloading and in it this statement is made, regarding pistol crimping and headspace.

Carroll Pilant of Sierra Bulltets says, " With most autoloading guns the cartridge headspace is actually set by the extractor holding the case head against the bolt face. So case mouth diameter is really no that important"

So who's right?

I reload for pistol only (one day I will get into bottlenecked rifle cartridges) and I love the Lee Factory Crimp Dies.

You bypass the "old school" crimp which can deform a non-cannalured bullet; they also provide better bullet retention because it compresses the brass all along the seated bullet (not just the mouth;crimp). Reliability in feeding is also supposed to be increased as the entire round is being sized to "factory" tolerances. Finlly, a pleaseant bonus is that as the name suggests, reloads now look like factory ammunition Love 'em!

I disagree with the "headspace not an issue thing." Most rimless semi-auto pistol cartridges are supposed to headspace on the case mouth by design. It's true the extractor will play a role. For instance you could shoot .40S&W in a 10mm auto simply from the extractor keeping it in place. Ditto the .357SIG in a .40S&W/10mm Auto (I heard the bullet just falls out from those who've witnessed)

However, I wouldn't feel safe in doing so for pressure-safety and reliabilty reasons.

End of the world scenario you do what you gotta to... for range plinking I make sure my reloads are all to spec.

 

[sunray]

Forget the crimp. Neck tension should be enough. Even in a semi-auto.

 

[Levi Garrett]

For many people reading this thread, there is a difference between crimping of handgun and rifle cartridges.

Most semi auto HANDGUN cartridges headspace on the case mouth. If you crimp too much, the cartridge will slide past the chamber and into the throat of the barrel, potentially creating very high pressures when fired. Also, if the cartridge moves forward, it will be away from the breech face, and away from the firing pin, causing misfires.

That is why there are taper crimp dies for most semi auto handgun calibres. They leave the front edge of the case mouth exposed for proper headspacing. The taper crimp die will tend to "squeeze" the bullet a bit, creating a ridge which will keep the bullet from being set back, along with the tension of the taper crimp.

For rifle cartridges, you can crimp, but it will decrease accuracy. If you are worried about bullet setback, then put a dab of lacquer on the bullet which will "glue" it to the case. Consistent neck tension is very important for accuracy.

Or you can get your own cannalure tool to put it where ever you want.

http://www.bulletswage.com/hct-1.htm

indeed

 

[beltfed]

For rifle cartridges, you can crimp, but it will decrease accuracy. ... Consistent neck tension is very important for accuracy.

It has been my experience that putting a light crimp on match bullets in fact increases both consistancy of velocities and consistancy of POI - and contrary to popular myth...increases accuracy. While I agree the average shooter won't notice the difference at 100m, at 400 + meters the difference is considerable.

I would peg the depth of the crimp as being no more than that made by pushing it down the bore at 2850 ft/sec.

75gr. Hornady HPBT crimped round, pulled bullet that has been crimped and a new non-crimped bullet out of the box. Crimping done with a Lee factory crimp die.

Same two bullets in the first picture, pulled crimped on the left and new out of the box on the right.

 

[carbonrod]

I was hoping you'd post some pics of pulled loads. Anyone that has seen beltfed shoot those will agree that those loads are very repeatable, and precise.

 

[sprint]

It has been my experience that putting a light crimp on match bullets in fact increases both consistancy of velocities and consistancy of POI - and contrary to popular myth...increases accuracy. While I agree the average shooter won't notice the difference at 100m, at 400 + meters the difference is considerable.

I would peg the depth of the crimp as being no more than that made by pushing it down the bore at 2850 ft/sec.

75gr. Hornady HPBT crimped round, pulled bullet that has been crimped and a new non-crimped bullet out of the box. Crimping done with a Lee factory crimp die.

Same two bullets in the first picture, pulled crimped on the left and new out of the box on the right.

More than satisfies my curiosity. Thanks for the detailed pics and for sharing the 'know-how'.

 

[SandRoad]

It has been my experience that putting a light crimp on match bullets in fact increases both consistancy of velocities and consistancy of POI - and contrary to popular myth...increases accuracy. While I agree the average shooter won't notice the difference at 100m, at 400 + meters the difference is considerable.

I would peg the depth of the crimp as being no more than that made by pushing it down the bore at 2850 ft/sec.

I absolutely agree with you, a light crimp will tend to keep neck tension consistent. Same with using an undersized expander.

I took it that the original poster was interested in making a substantial crimp into a cannelure, to physically hold the bullet in place for use in autoloaders. A heavy crimp in a non cannelured bullet will tend to deform the bullet, especially if the bullet doesn't have a bonded core. I have done a few of of this type of crimp and found that it didn't help accuracy. I wasn't using the Lee FCD in that case.

Thank you for the pictures. Very informative as I have not pulled a rifle round crimped with a LEE FCD.

I use LEE FCD dies in all handgun calibers and some rifle calibers.

 

[beltfed]

I took it that the original poster was interested in making a substantial crimp into a cannelure, to physically hold the bullet in place for use in autoloaders.

I think even a marginal crimp creates enough of a 'lip' or crease in the bullet to prevent setback, and is superior to any neck-only tension. The load is typical of the ammo I create for all my autos.

 

[RT]

Interesting discussion...Ive been reloading 9mm for years, and have started to question the crimp Im using. With a inertia bullet puller, it takes about 3-4 stout hits on a piece of wood to get the bullet out. The bullet shows no marks as to were it was crimped, and the bullet cant be moved by hand once it has been seated/crimped. Im using a Lee 1000.

An thoughts about this crimp or how to determine the the best crimp?

 

[commonman]

BeltFed, thanks for the great pics. Wish I could have read this months ago as it would have saved me a lot of experimenting. The crimping method I settled on looks exactly like yours and does improve accuracy. I especially noticed it in one particular rifle in which the difference between crimped loads and uncrimped loads is dramatic.

Again, appreciate you all sharing your hard earned experience.

 

[BCFred]

I kind of kept greying out and having flashbacks on this issue. I think there was big argument between Lee and some others in the loading business, way back when, about the "factory advantage". If I recall correctly, the story went that factory made rounds were crimped and this gave them an advantage in consistent ignition and accuracy. Lee claimed that their crimping dies, which I like and use if I crimp, allowed one to also crimp and get the same advantage. The argument seesawed back and forth with equally knowledgable people saying "baloney" and pointing out things like benchresters, who absolutely require superior accuracy, never crimp and so on. The hype all kind of died out eventually. Personally I never found much difference in accuracy between crimped and non-crimped in my hunting rifles and couldn't convince myself that there was more consistent ignition from chronograph results either. I kept thinking I saw a difference in variability of velocities, because it sort of made sense there might be one, but any differences just kept disappearing with more testing. On the other hand, I was often testing for accuracy at 100 meters and felt I should look further out someday. But I thought at the time that any difference would probably show the crimped bullets to be less accurate because of deformation of the jackets. I knew severely deformed jackets had that effect even at 100 meters. Never got around to actually doing the long range testing though, and today people are saying bullets without a cannular that are crimped are more accurate way out there. Don't know what to think about that... Jeez life can get complicated sometimes... Personally I'm going to stick with cannulas for crimping, but I'd like to be shown some good data on this.