Crimping Insight Wanted

Status
Not open for further replies.
F

film495

Member
Joined
Aug 26, 2019
Messages
2,838
So, I have some dies out in my mailbox (RCBS .38 Special set), but did not go get them yet. Maybe this weekend I'll get to practice with them some and then consider if I want to get out power and primers, but I'll likely practice with them several times before considering trying to make live rounds.

For those experienced people out there - what is with crimping? Most info and videos I see people just do it by eye. They crimp and look at it and decide if that looks good or not. How do you determine how much crimp to put on?

I would think one could tell by feel, but I've never done it before, so what do I know? I would think an amount of pressure to make the crimp would be more valid than eyeballing what the crimp looks like, but again, what do I know? - nada

To much crimp is bad, to little is bad, how do you know what is right? Do you just compare it to a factory round? and do it by appearance? Do you see how hard it is to actually pull the bullet out of the crimped cartridge? I'd think there would be some spec for how much force would be required for the bulled to exit the cartridge, but have not found any such info on any type of process being used to test/check such a thing.
 
It does give a spec of # of turns to set the roll crimp. So, that is good. It then says inspect and adjust as necessary until satisfied, but provides no information about what might be considered as satisfactory or not for a roll crimp. They give some specs for taper crimp, but these dies are for a roll crimp.
 
What caliber do you want to crimp?

A bunch of pics here.

https://www.thehighroad.org/index.php?threads/how-much-crimp-lee-fcd-guidance-sought.469815/

Like this one.
index.php


.
 
This like other things in reloading, you have to develop a feel, everybody has to walk the walk and come out on the other end, experienced. Just creep up on the crimp, little by little, 1/8 turn at a time, inspecting each time. It goes without saying, all your cases has to the right length for the crimps to be all the same. I crimp minimally as possible.
 
film495 said:
.38 Special LSWC, target loads for first reloading work ..
Click to expand...
I sort my revolver brass by head stamp, this usually provides the most consistent neck tension on the bullet. When resizing the brass the resistance should feel consistent, if not it will effect performance. Faster powders like Bullseye and W-231 are good choices for a 158gr lead bullet in .38 spl. I trim all of my revolver brass to the same length to ensure a consistent crimp, many reloading manuals show a "trim to length" measurement.
You can access a wealth of reloading data from powder manufacturers along with reloading procedures such as crimping https://www.scribd.com/document/365559935/Lyman-48th-Reloading-Handbook .
I should add this, along with my revolver brass sorted by head stamp it is also been fired and reloaded the same number of times, as the brass is fired and reloaded it becomes harder so again this is about consistency. And this will show up on your target and chronogragh numbers.
 
Last edited:
Caliber, gun and bullet matter. If using a plated bullet you can crimp too much. Most 38 loads only need a minimal crimp. A full power 357 load with slow powder needs a heavier crimp so more pressure builds which in turn helps the powder to burn more completely. You can crimp more with a lead bullet with a crimp groove than one with cannelure
 
Last edited:
The first item you should have gotten is a quality reloading manual, I have Lee Modern Reloading Second Edition, Lyman 50th Edition Reloading Handbook and Hornady Handbook of Cartridge Reloading 9th Edition. ( Hornady 10th Edition is now out) There are many others from bullet manufacturers etc. Once you have one, read the first part of the manual which is instructional. It will give a lot of good info on the subject including case crimping. Then re-read that section. You will better understand the terminology you hear from other reloaders and have a better understanding of things like crimping, pressure signs and so on. Then is when you should begin to reload, when you have a question refer to your manual for insight. My first manual was the Lee, it came with my press kit, I read it three times. I have read the front of each of my manuals at least twice. I also will go back from time to time and read the front section again. I enjoy it and I retain more info each time. Just my $.02 .
 
Like was written, back off the seater plug and screw the seater die down an 1/8th of a turn and crimp.

Check it and go down another 1/8th of a turn until you think it is right. .

When you seat the bullet to the proper depth you will ser and feel the edge of the case by the projectile. After crimping that little step will vanash.

MAKE SURE TO BACK UP THE SEATER PLUG BEFORE CRIMPING.

You can buy a Lee Factory Crimp Die on e bay delivered for under $20.

I have bought a bunch of them in a lot of calibers. Roll crimp dies and taper crimp dies.

Good luck, have fun & be safe.
 
There are two reason to crimp a round.
The most important is to augment neck tension. You want to keep the bullet from moving either in or out of the brass when shooting. Moving in raises pressure and if it moves out it can tie up the cylinder preventing rotation.
I have some 38 SPL loads that are so light I just straighten the flare as the bullet will not move out of the brass as the revolver is fired.
The other reason is to promote complete combustion of the propellant.
Your crimp should have the case neck lip end up in the top half of the crimp groove of the bullet. Then when applying the crimp it folds into the groove and ends up biteing in the middle of it. The amount of crimp (locking action) needed will depend on the bullet weight and charge. The lighter the crimp the less the brass is worked and makes for less brass splitting over time. You will need to experiment on how much is enough to keep the bullet from moving as that is the "learning curve". Another challenge for you.;)
 
The 38 Special is a very "forgiving" cartridge to reload and an excellent cartridge for a new reloader. One method I suggest for new reloader's crimping is to compare your crimp to a factory crimp, or print the first pic in the thread Walkalong linked. Make your crimp using "C" or "D" in the pic as an example. For the 38 Special a "precision" crimp isn't necessary so slight variations in case length or slight differences in crimp and eyeballing the amount is OK. When you get used to reloading, you will be able to "tweek" your crimping...

K.I.S.S.!
 
Lots of good advice above. I also like to compare mine to a factory loaded round. Sometimes your load isn't exactly the same, but you can get a good idea of how much crimp usually by looking at a similar factory round.
 
lots of good info here - taking in a lot, gives me a little basis for doing some testing with the dies, probably just cases and bullets to get a feel for it for a while, this is the bullet type from speer 158 grain LSWC

speer.jpg
 
no powder or primer, but got one seated and crimped, more or less correctly I think. I admit I found it kind of difficult to tell exactly how deep to seat the bullet to line up the case mouth to be aligned with the crimp groove. not sure I go it right, but close in the second try after I bungled the first one. at least it appears all the equipment is correct and working correctly.
 

Attachments

  • IMG_20200110_203407779.jpg
    IMG_20200110_203407779.jpg
    100.3 KB · Views: 48
Being new to reloading it took me a little bit of trial and error to get it down. One thing I do is read up the information on the bullet I am seating. If the spec calls for an oal of 1.470 for example I sneak up on it with a pair of calipers even if it has a cannelure. Once everything is close as my equipment allows i do a batch of 50 at a time. When seating on my press I can feel the handle just cam over from time to time I do compare to factory ammo. When you do a few you will pick up the feel. 38 special and .357 are probably my favorite to load as far as being forgiving.
 
It's all a matter of trial and a general knowledge of the purpose of crimp. Some times you need heavy crimp to prevent bullet pulling in heavy recoiling revolvers, or you may need heavy crimp to aid consistent ignition of large charges of slow burning powder. Auto pistol cases generally have no crimp beyond that needed to remove the expanded case mouth or maybe some taper crimp applied if neck tension is inadequate.

You will probably mangle a few cases along the way in the learning process (I know I did) but eventually the degree of crimp you need to apply will become almost second nature.
 
film495 said:
lots of good info here - taking in a lot, gives me a little basis for doing some testing with the dies, probably just cases and bullets to get a feel for it for a while, this is the bullet type from speer 158 grain LSWC

View attachment 883332
Click to expand...
That is one butt ugly bullet right there.
It looks like it was tumble lubed in a bucket of rocks...
just sayin' :uhoh:
 
@film495 looks like you got it! All good advice from THR, make sure you’re diligent in the trim/case length step as that will help keep the amount of roll crimp consistent. When you settle on the load, fire 5 and measure the 6th to see if there’s any change. .38’s a great cartridge to load for, and I only apply a light roll crimp. The only revolver load I have to watch carefully is the .460, mine requires a really really tight crimp.
 
It was interesting, the one on the right I did the crimp exactly as in the RCBS directions. with the press I could really feel it bite down doing the crimp, so - pretty sure I could feel if one was off when seating/crimping. The dies were new, so I did put a touch of case lube on cases when resizing, just a dab on cases 1,5,15, and 30 - could sort of feel when the resistance went up a touch and I know not needed for carbide die, but a lot of people say they do a little bit anyways - so, figured it didn't add much time to the process at all, so - worth trying.

I didn't lube the case mouths for expanding belling, all I did was just put a touch of sizing wax on the sizer inside the die, like barely any - just a real skim coat, seemed to work, went through 50 cases no issue. I do have a case trimmer, but have not worked with it or set it up for .38 Special as of yet. This is my once fired federal brass, so - I'm giving them the benefit of doubt on case length.

one thing I ran into somewhere was the notion that if the finished .38 Special case will drop correctly into a case gauge, which these did, you're good to go as far as crimp goes, the case gauge will pick up if the crimp is too soft, and any bulges etc. if it is too strong.

these aren't live rounds, there's no primer or powder in these, just testing working with the dies. If I can get it down I may make a dozen real ones to take with me to the range tomorrow.
 
Status
Not open for further replies.

Similar threads

S
  • Locked
Crimping rifle rounds
Replies
6
Views
1K
30Cal
3
Highland Lofts
  • Locked
Prefered Crimping
Replies
23
Views
749
Kevin Keith
Kevin Keith
G
  • Locked
Military crimp
Replies
13
Views
5K
tlen
T
S
  • Locked
Questions about crimping.
Replies
6
Views
426
James2
J
C
  • Locked
crimping
Replies
8
Views
638
Matt Dillon
M
Back
Top