Firstly there are 2 utterly different "Lee factory crimp dies", one for what seem to be bottleneck rifle cases, & the other (called a "Carbide Factory Crimp Die"), for strait-wall pistol cases.

 

The rifle type uses a tapered collet to imprint or squeeze the case mouth into the callelure of the bullet.

 

The pistol type uses a carbide sleeve to "iron" the case walls & a seperate taper, or roll crimp type depending on the caliber.

 

I hope the die works as advertised because I have one on order! Supposedly the carbide taper crimp die is more forgiving about different case lengths & has a different internal profile from the older dies in the die sets. I'm hoping it will give me independant adjustment for bullet seating & consistent crimping without having to do the double adjustment I need to now because I seat & crimp with a single die. Partly this is to make the switch from jacketed hollow points to plated lead simpler too because of the different crimp required of the 2 kinds of bullet construction will be easier to adjust for.

 

If it makes a difference I'm using a 4-stage progressive press instead of a single stage type, so for me it won't involve yet another pass through the press, it'll just use the currently empty 4th station.

Steve, thanks for the link I've seen that before but it does give everyone a chance to read what Lee says about the die. I have a few thoughts though.

Remember, what is written at the link was written by an ad man who works for Lee.

If the die sizes the case as it crimps the case in the crimping groove wouldn't it resize the bullet at the same time since the bullet is inside the case? Now if the bullet is sized to the inside diameter of the case would it be too small to properly fit the bore?

If the length of the case is not critical to the die could it be the wrong length for the chamber of a semi-auto pistol? Since most semi-auto cartridges head space on the case mouth I've been taught that the cartridge length was some what critical. Have I been taught incorrectly?

In the case of a revolver cartridge if the case length isn't critical then would each crimp be slightly different there by giving a different bullet pull to each cartridge and giving radically different velocities? Wouldn't this be bad for accuracy?

 

In the case of Dillon dies with the separate crimping die Mike Dillon makes the claim that this enhances accuracy but DOES NOT claim that case length isn't critical.

I've use Dillon, Hornady, Lee, Lyman and RCBS dies (in alphabetical order only) and have produced excellent ammunition with them all. I have used the Lee factory crimp dies for bottle neck cases and found no difference in accuracy with or without. I don't advocate spending the extra money for the Lee die for that reason and for the reasons above. I don't use Lee dies anymore.

By all means do as you see fit this is my opinion and these are my questions.

 

Peace Bros.

Not to be a spoil-sport, but I've been using the Redding Profile Crimp Die for decades on all my straight-wall cases. Before that, I had problems with inconsistent crimps and poor accuracy. These work very well, giving much tighter, more uniform crimps, and accuracy has improved with their use. The first one I tried was for my .357 SuperMag, it worked so well I have bought one for all of my revolver handgun cases.

I have to state in advance that I really do like Lee dies. (other than the rubber O-ring which I tend to swap out with a standard lock ring)

And I do use Lee die sets often, as well as RCBS, Dillon, Redding dies, etc. and other brands of reloading dies.

My original plan was to purchase a .40S&W Lee Carbide Factory Crimp Die, to be used for a brass bulge buster kit. The price was pretty darn good for carbide dies, so I decided to get a handful of them, in most of the common calibers.

I have had no problems what so ever using the Lee Carbide Factory Crimp Die to assemble jacketed ammunition.

The Lee Carbide FCD has a carbide re sizing ring inside the die that full length sizes an already loaded cartridge after the crimping stage, to help assure that the loaded cartridge is correctly sized to SAAMI specifications, and that the cartridge will successfully chamber in your firearm.

If your loaded crimped cartridge is already the correct size, or undersize... Then the carbide ring does not even touch the brass, and the die will not re-size the cartridge.

Sounds great on paper right? Well as long as you don't mind full length sizing a cartridge twice. Of course if you load your cartridges correctly in the first place, It doesn't really happen, so is it even necessary?

My problems with the Lee FCD first appeared when loading over sized .452 diameter cast lead bullets in the 45acp cartridge.

I have slugged most of my 45's and they all require at least a .452  or larger sized cast lead bullet to fit the barrel properly. A smaller bullet causes gas leaks, and results in barrel leading, and horrible accuracy in my guns.

When I assemble a loaded cast lead .452 cartridge in 45acp using the Lee FCD, the carbide ring in the die swaged, or squeezed down my over size lead bullet through the cartridge brass, making it too small. Pulling a bullet, and running a micrometer over the projectile quickly shows the problem.

I have an example pictured below.

This was a relatively hard bullet that was sized to .452 and cast from almost pure Linotype. While it pictures quite well, it's really unnecessarily hard for use in the 45acp cartridge. I loaded this round with the Lee FCD, and disassembled it using a kinetic bullet puller to measure the loaded projectiles diameter.

The Lee FCD has swaged down the hard .452 bullet, to .451 diameter. A typical soft.45acp alloy like 50/50 pure lead/wheel weight lead, or just even straight wheel weight lead has even less resistance to sizing spring back, and can potentially be swaged down more by the Lee FCD. (in extreme cases .450 or more)

Shooting an undersized cast lead bullet tends to result in barrel leading from gas leaks due to poor bullet fit, as well as poor accuracy. Removing the Lee FCD from my cast lead bullet loading regimen quickly makes this problem go away.

It seems somewhat counter productive to take the time to slug your barrel, and then size the bullet to fit the barrel, only to have the Lee FCD swage down your bullet thereby making it under size.

While the re sized.451 bullet loaded with the Lee FCD fits easily into a case check gauge...So do .452 bullets assembled using a normal RCBS taper crimp, or roll crimp.

The Lee FCD can also swage down oversize cast lead bullets in other calibers.

9mm - .358 sized cast lead bullet swaged down to .355

38/.357Mag - .359 sized cast lead bullet swaged down to .356

40S&W/10mm - .402 sized cast lead bullet swaged down to .399-.400

44Mag - .433 sized cast lead bullets swaged down to .430 (really bad in 44 rifles)

The hardness of your bullet, as well as the thickness of the brand of cartridge brass can vary the amount of sizing down, from none to way too much. In the end I simply found it was easier to not use the Lee FCD with my oversize cast lead bullets at all.

The Lee FCD does however work great when assembling standard size jacketed ammunition, but then so do most of the other die brands.

I tend to take my time loading small batches of ammunition single stage to get things "just right" for my personal target shooting these days. I also gauge all of my loaded ammunition with a case check gauge, to assure that it will chamber. It helps catch any accidents before I am on the range.

If I still loaded large amounts of jacketed ammunition commercially, on automated or progressive re loaders, I might be tempted to use the Lee FCD as a safety check, sort of like a powder cop die to help assure that everything was in specification, but I don't anymore, so I don't really find the Lee FCD necessary for the type of hand loading that I do.

I have used a disassembled Lee FCD as a carbide full length push through sizer die, to remove the guppy, or bulge from brass that was fired in an unsupported chamber.

The Lee Carbide FCD is a useful loading tool for the assembly of jacketed ammunition, and can be a handy part of your reloading tool box, as long as you are aware of it's drawbacks when using it with over sized cast lead bullets.

 

- Bullwolf
 

Slugging a bore is basically forcing a soft oversized lead "slug" through the bore. After the lead has been swaged (squeezed) down to the tightest internal dimension  by passing through the bore it is removed & measured as a kind of "negative image" of the bore.

 

Soft lead (the softer the better) is the trick, together with lots of lube everywhere & a good technique for pounding the lubed slug through the bore & catching it on exit. Usually short lengths of wood dowel are used (a single long one might bend or splinter in the bore) & a rubber mallet for the actual hammering. pure lead fishing weights that you can gouge with a fingernail are a frequent candidate as they are cheap, available & come in many cylindrical shapes.

It depends on why exactly you're looking for an individual measurement. To calculate the size for swaged or cast bullets you measure the maximum diameter, to check things like rifling depth you measure maximum, minimum & subtract one from the other & diivide by 2.

 

Rermember though any measurement will be the minimum diameter throughout the bore. Just as an example lets say the bore is nominally .356 acrross the lands & .358 across the groves. However ther is a tight spot that occured during manufacturong where these are .001 tighter. The slug wil show .355 & .357 because it had to pass through the constriction.

mister callan said
Slugging a bore is basically forcing a soft oversized lead "slug" through the bore. After the lead has been swaged (squeezed) down to the tightest internal dimension  by passing through the bore it is removed & measured as a kind of "negative image" of the bore.

 

Soft lead (the softer the better) is the trick, together with lots of lube everywhere & a good technique for pounding the lubed slug through the bore & catching it on exit. Usually short lengths of wood dowel are used (a single long one might bend or splinter in the bore)

 

Excellent advice.

 

I might add to the above quote, that if you must use wood, be sure to use a good solid piece of hard wood dowel. I personally prefer to use a short length of brass rod, much like I would use for a squib clearing rod to drive a slug through a barrel. I also like to wrap the brass rod in the front and back with some electrical tape, so the metal part of the rod doesn't come into contact the inside of the barrel. Think sort of like the O-rings on an Outers foul-out rod.

You can save yourself a lot of headache and hassle later on down the road by using something solid to push the slug, or a squib round through the barrel with.

It is definitely not fun to get a stuck bullet, or slug jammed in the bore, and then compound the problem with a broken piece of soft wood.

Generously lubricating the barrel that you plan on slugging, is also another good piece of advice.

It really isn't as complicated as it sounds to slug a barrel. Just lube it up, and pound the slug on through, it's not rocket science. People have been doing it for years, and it wont hurt the bore any to do so.

You do want to use a dead soft (pure) piece of lead if possible. Harder lead can "spring back" a bit, and tends to give you erroneous readings.

This is one of the reasons fishing lead weights are often suggested, just make sure that it really IS a lead weight, and not zinc, tin, or some other kind of harder environmentally safe alloy.  If you happen to be a bullet caster, you can do close to the same thing from say stick on tape wheel weights, or plumbing lead usually.

Fishing sinkers just happen to be convenient, as they are already cast, and often close to the desired shape and diameter.

Another commonly used possible slug, is a slightly larger than caliber size muzzle loading ball, as they are often made from pure soft lead. The only downside to using muzzle loading balls, is that you typically have to buy more than you need or want (like a box of 100) to just get a single ball to slug your bore with.

If your potential slug is a little bit too small... Don't fret, you can give it a bit of a squeeze in a vice, or a whack it with a hammer to bump the size up a some for your desired application.

While slugging a bore, be sure to pay close attention to the felt resistance while driving the slug through the bore. If you notice that you have any tight or loose spots.....Consider slugging the bore from both ends. Simply push a slug in a few inches, then tap it out, and do the same from the other end. Measure both slugs, and then compare for any differences.

This way you can tell if the barrel has a constriction at some point, like say around the forcing cone, (from perhaps crush fit threads on a non Dan Wesson, or a heavy stamped roll mark) or the opposite, maybe an unseen bulge in the middle or what not.

 

- Bullwolf