Bullet Seats Deeper During Crimping Step

[Racer X]

I am loading cast bullets in my 45 Colt using the RCBS Cowboy dies. The bullet is the RCBS 270 SAA bullet.

Here's my problem. I am seating and crimping in two separate steps. I first seat the bullet to my desired OAL of 1.65". Next, I remove the seater plug and set the desired crimp. However, after I crimp, the bullet seats another .010 - .015" deeper.

Any ideas on what I am doing wrong? Am I over crimping?

[stimpylu32]

Racer X

If your using a roll crimp and I think you are , as the brass is rolled in it will pull the bullet down , the easy fix is to just seat the bullet .010 less and let the crimp do the rest of the work .

Now the best fix is to use a different crimp die like the Lee FCD or one of the other taper crimp dies , as they don't pull down on the bullet as much .

stimpy

[Racer X]

Racer X

If your using a roll crimp and I think you are , as the brass is rolled in it will pull the bullet down , the easy fix is to just seat the bullet .010 less and let the crimp do the rest
Now the best fix is to use a different crimp die like the Lee FCD or one of the other taper crimp dies , as they don't pull down on the bullet as much .

stimpy

stimpylu32, Thank you for your reply. I have seated longer than my desired OAL and then crimped and that seemed to help. I was just wondering if what I was experiencing was normal, as I have never noticed it happening before.

I have both the Redding Proflie Crimp and Lee FCD. I stopped using the Lee because I heard it also sizes cast bullets as it crimps and I don't want that happening. As for the Redding, I got tired of having to lube each case before I crimped it, so I switched back to the RCBS seater die and use it for crimping.

 

[stimpylu32]

Racer X

I don't use the Lee FCD with cast pistol bullets much , so not sure about the re-sizing thing , for cast I like a firm roll crimp and use the seating die to seat & crimp in the same stroke .

It works well once you get the die set , I do have to pull the seating plug every so often to clean excess lube or it will start seating the bullets too deep due to lube build up .

stimpy 

[Catfish]

Just a silly question. Why not do it in 1 step if you can? I always seat and crimp at the same time.

[calvon]

A few years back I had problems loading cast in .40 S&W using RCBS dies. If I set the die to engage the crimp feature it always set the bullet a tad deeper during crimping which brought about shaving up a little curl of lead on the mouth of the brass. Couldn't chamber the durn things.

Solved the problem by purchasing a Redding Taper Crimp Die. Set the RCBS Seater die a turn short of engaging the crimp feature and adjusting the seater stem to get the desired OAL. Then, a trip through the Redding. This added a step to my single stage press reloading procedure but it eliminated the fail to chamber problem.

[wncchester]

"Any ideas on what I am doing wrong? Am I over crimping?"

You are probably crimping on to the rear edge of the crimping groove.  If so, the rolled in brass simply pinches into the edge and pulls the bullets further in. 

Why are you choosing an arbritary OAL for a cast bullet revolver load?

[Racer X]

Why are you choosing an arbritary OAL for a cast bullet revolver load?

My OAL is not arbritary. It is the recommended length for that bullet, assuming a correct case trim length. I seat the bullet until the case mouth covers most of the crimp groove. The bullet is the RCBS 270 SAA design.

[wncchester]

"My OAL is not arbritary. It is the recommended length for that bullet, assuming a correct case trim length."

It is arbritary in the book.  The book OAL is not based on anything except that was the lenght they used when developing their data.  Book OAL is NOT a law to be slavishly followed, it's only a starting place.  And "correct" case trim length has no effect on OAL, case  length differences simply change how deeply each bullet sits inside, but  case length does affect crimping.

One of the prime advantages in hand loading is the opportunity to custom make our ammo.  Simply duplicating a book load as it it were a law defeats that advantage.  Experiment to find the best charge and OAL for your own weapon and then load as you need to load.  

[Autorim]

Racer X. I think you are seating correctly - anyway that's what I have been doing for a lot of years. I seat all cast bullets to the top of the crimping groove and crimp in a separate operation. Before seating live ammo, I always load dummy rounds and check chambering. Some bullets will protrude from the front of the cylinder if seated as discussed.

IME seating and crimping in one operation is subject to shaving lead from the bullet.

Ken

[Steve P]

The top edge of the bullet cannelure and/or crimp groove should be within .001-.002" of the edge of your case mouth.  This means you should be able to see a line there, propbably feel it with a finger nail, but no more.  As you apply crimp, the mouth of the brass case goes into the cannelure, or goes into the void which is the crimp groove.  If you are actually pulling the bullet in more, then the crimp, as it rolls in, is not just going into the void, it is hitting against the next lower driving band of the bullet.  

ALWAYS seat bullets them come back to crimp.  It is ok to set your die to move a belled case mouth in a little as the bullet is finishing its seat.  This helps you see when the top edge of the crimp groove is just coming even with the case mouth.  DO NOT crimp as bullet is being seated into the case.  That is like trying to shut your garage door as you drive your car in.  Eventually the door is going to hit the car.  (Longer brass, excess lube on tip of bullet, etc will destroy round if crimping while seating.)  Seating in two steps gives you one additional opportunity to inspect bullet to case mouth match before crimping.

Sounds like you are doing everything right.  Possibly crimp groove is a little too high of case mouth when bullet is seated.  Try seating bullet about .010" deeper.  Remember, OAL is someones elses reference point on what they did one day with one bullet and one gun as they were logging information to put into their book.  Your gun, your bullet, and your ammo could, and probably should be, different when you log it in YOUR book.

Steve

[stimpylu32]

ALWAYS seat bullets them come back to crimp.  It is ok to set your die to move a belled case mouth in a little as the bullet is finishing its seat.  This helps you see when the top edge of the crimp groove is just coming even with the case mouth.  DO NOT crimp as bullet is being seated into the case.  That is like trying to shut your garage door as you drive your car in.  Eventually the door is going to hit the car.  (Longer brass, excess lube on tip of bullet, etc will destroy round if crimping while seating.)  Seating in two steps gives you one additional opportunity to inspect bullet to case mouth match before crimping.

Sounds like you are doing everything right.  Possibly crimp groove is a little too high of case mouth when bullet is seated.  Try seating bullet about .010" deeper.  Remember, OAL is someones elses reference point on what they did one day with one bullet and one gun as they were logging information to put into their book.  Your gun, your bullet, and your ammo could, and probably should be, different when you log it in YOUR book.

I have a couple questions concerning the highlighted ( RED ) statements , first , if seating and crimping in the same pass is such a bad thing , then why are the dies made to do exactly that ?

And second , the OAL listed in the manuals are what the tester set for the load being used to determine the pressure of the load being tested , a shorter COL means that the bullet is seated deeper into the case , thus lowering the case cap and changing the pressure curve of said round , while this may not make a difference in some cartridges , it can and does in others  , leading to very dangerous pressures .

stimpylu32

[Lloyd Smale]

I too prefer to seat and crimp at different stations on the press but will be the first to admit that if your die is set properly theres very little differnce in the finished product.