I need a primer on crimping

[ghh3rd]

I don't understand crimping.

I'm embarrased to say that, after loading and using several hundred .38's. I used the fourth die in my set to crimp them, just enough to see the crimp (I think). I was worried about crimping too much and wearing out the brass early, or creating higher pressures.

Although I have the fourth, crimping die, I hear that many crimp without it, using just the bullet seating die. I really don't understand how that works and would love to know more.

I just loaded my first batch of .40 S&W (175 gr boolit with 5.5 gr Accurate #5). I was about to install the fourth die to crimp them, and decided to post this first to see how much of a crimp I should put on them, and how to tell (visually) if I've got the right amount.

Sorry I'm so 'crimp challenged', but I figured that I could get help for this afflication here.

Randy

[IllinoisCoyoteHunter]

I make a dummy round with no primer or powder. Get the bullet seated your COL. Then back your seating plug out almost all the way. Put the dummy round in the shellholder and raise the ram. Screw the die IN untill you feel it come in firm contact with the mouth of the case. Lower the ram and then screw in 1/4 to 1/2 turn. If you need more or less crimp, this can be achieved by screwing in or backing out the die, respectively. Then raise the ram with the bullet in it to the top of the stroke and screw in the seating plug until it comes in firm contact with the tip of the bullet in your dummy round. Thats it!

[xr650]

I just loaded my first .40's with cast.
Seating and crimping in the same die caused the lead to push in front of the brass. My 226 ate them fine, but my XD would not chamber most of them.
I seated without crimping and used a Lee crimp die and the XD did fine as did the 226.

I also tried a Lee FCD and it sized the lead down. Once again no problems with the 226 but the XD leaded.

[JW6108]

This is how I do it, not saying it's the best or only way, but it works for me. YMMV

**I like to seat the bullet and apply the crimp in separate steps.
(I tried seating and crimping simultaneously many years ago, but it just didn't work for me.)

Semi-automatic pistols: same as **, apply taper crimp. Roll crimping may interfere with the case's ability to properly headspace.

Revolvers: same as **, for semiwadcutter bullets, apply roll crimp using bullet seating die. Light crimp for light loads, heavier crimp for heavier loads. For flush seated wadcutters, apply taper crimp or roll crimp, as you prefer. I like taper crimp for these.

Crimp helps to make bullet pull more uniform, which aids accuracy. Also, many powders will not burn efficiently unless adequate crimp is used (not excessive). With revolvers, there is some risk in having uncrimped bullets jump the case under recoil, sometimes protruding from the front of the cylinder and tying the gun up. I probably crimp a little heavier than some folks, but doing so has worked well for me in the 30+ years I have been at it.

Will you eventually get case mouth cracks?; yes, but in .38 Special I have gotten 8+ loadings with some brass before this started to occur. It seems that splits in the body of the case are nearly as likely to show up as case neck splits; either way, they don't last forever.

Good luck.

[HeavyMetal]

Crimping is indeed an issue.

Currently the "taper" crimp is all the rage. Sadly this style crimp offers the most chance of being way to much crimp long before it is visually seen as to much! AKA "over crimping"!

For a first timer I'm going to suggest you get a pair of dial calipers. "Mike" your case, at the mouth, after you resize.

Now run them into the expander die just deep enough that you can set a boolit in the case mouth and run it into the seating die without it falling out! Do not crimp in the same step you are seating the boolit!

Now once you have the boolit depth set take your crimp die and screw it into your press. Remove the taper crimp parts from the die at this point! Put a boolit in the shell holder and run it to the end of the ram travel. Make sure the base of the die is against the shell holder and the tighten the locknut while you maintian pressure against the die base! This make the die square with the ram!

Now put the taper crimp parts back in the die and slowly turn them in until you can just feel them touch the case mouth.

This may be very hard to do with the Lee FCD die which is why you took a diameter reading off the freshly sized case mouth. What you want to do is turn the crimp section in until you have no more than a .003 smaller case mouth! This will be in the first .025 of the case right at the mouth.

Once this is done you can now play with crimp depth and see what works best in your gun. Be aware that more than .010 smaller than your sized case mouth dimension will severly size your boolit and cause accuracy problems.

These suggestions are strictly for auto case's being taper crimped. Roll crimping a revolver round is a whole nother story and set up style!

[44man]

I spent years experimenting with crimp and case tension on revolver bullets/boolits. I found even and good case tension is the most important.
I tried crimps from a full profile (Ala-Freedom factory loads.) to no crimp at all, shooting one at a time. In no case could I find that crimp aids accuracy or burn rate.
I now just crimp enough so that if I load six and shoot five, the last boolit is still where it belongs.
However if case tension varies a great deal, accuracy just flies over head and laughs. [smilie=1:
As far as shortening case life, I have .44 brass that is going on 50 re-loads without a loss. Normally a split neck will happen on the first loading because of a defect in that case. I lost a few .475 cases on the first loading but the rest are doing great after many, many loadings. I suppose if you over crimp, brass life will be shorter.
I found you should never try to anneal revolver brass unless you shoot very light loads. You will lose boolits FAST.
Rifle brass is another story.
Brass is funny stuff. It seems the stuff lasts years if used but if just left sitting for a long time it can get brittle.
When I had trouble getting 6.5X55 brass I made cases out of new 30-06 brass. It worked fine but then regular brass came out so I left the formed loads sit for years. All the necks split. These were annealed, formed, turned and reamed and annealed again. I have to wonder how wildcat cases hold up! :confused:

[Naphtali]

I am uncertain where this information fits within the picture being painted. My reloading guru, a former commercial bullet caster who now reloads and shoots tens of thousands of round per year, informs me that he uses Lee's factory crimp dies when loading jacketed bullets. BUT when reloading cast bullets having crimp groove, he strongly prefers to use Redding's profile crimp dies.

[JW6108]

I don't understand crimping.

I'm embarrased to say that, after loading and using several hundred .38's. I used the fourth die in my set to crimp them, just enough to see the crimp (I think). I was worried about crimping too much and wearing out the brass early, or creating higher pressures.

Although I have the fourth, crimping die, I hear that many crimp without it, using just the bullet seating die. I really don't understand how that works and would love to know more.

I just loaded my first batch of .40 S&W (175 gr boolit with 5.5 gr Accurate #5). I was about to install the fourth die to crimp them, and decided to post this first to see how much of a crimp I should put on them, and how to tell (visually) if I've got the right amount.

Sorry I'm so 'crimp challenged', but I figured that I could get help for this afflication here.

Randy

This is worth a read:

http://www.exteriorballistics.com/reloadbasics/crimp.cfm