“Is That Enough Crimp?” (or “Learning to Reload, Part 1”)

[lovemywoods]

Learning a new skill is often about learning new techniques and acquiring new insights. Sometimes it’s learning how not to do something. I recently learned how not to crimp ammo!

After attending one of Aszerigan’s reloading classes, I decided to take the plunge and get into reloading. I’m keeping it simple to start. (Oh, don’t blame Aszerigan for my crimping goof; we didn’t cover that…)


First, I built a bench. See the link below:

https://www.indianagunowners.com/forums/ammunition_and_reloading/116529-built_my_own_reloading_bench.html#post1413671


Then I started loading 9mm rounds. After the initial few steps, I set up the seating and crimping die. I found the instructions a bit vague about knowing how much crimp is enough. Well, in my noobness, I put WAY to much crimp in the die. Then, when I went to seat the bullet, it stopped early in the overzealous crimp and I continued to apply force to the press handle. I didn’t know how much is too much!

Well, here’s what came out of the press. I wrote the sarcastic note to myself. Thought I’d share it with my INGO friends.

Everything did turn out OK. Here is a picture of my first box of reloaded ammo off my bench!!! Yea!

 

[jblomenberg16]

Learning a new skill is often about learning new techniques and acquiring new insights. Sometimes it’s learning how not to do something. I recently learned how not to crimp ammo!

After attending one of Aszerigan’s reloading classes, I decided to take the plunge and get into reloading. I’m keeping it simple to start. (Oh, don’t blame Aszerigan for my crimping goof; we didn’t cover that…)


First, I built a bench. See the link below:

https://www.indianagunowners.com/forums/ammunition_and_reloading/116529-built_my_own_reloading_bench.html#post1413671


Then I started loading 9mm rounds. After the initial few steps, I set up the seating and crimping die. I found the instructions a bit vague about knowing how much crimp is enough. Well, in my noobness, I put WAY to much crimp in the die. Then, when I went to seat the bullet, it stopped early in the overzealous crimp and I continued to apply force to the press handle. I didn’t know how much is too much!

Well, here’s what came out of the press. I wrote the sarcastic note to myself. Thought I’d share it with my INGO friends.

Everything did turn out OK. Here is a picture of my first box of reloaded ammo off my bench!!! Yea!

My that looks familiar! I did the same thing on more than one occasion myself! I also learned how not to flare a case! I could have probably put a .40 in my first 9mm case that I flared!

BTW...that looks like a great load for general purpose 9mm. I like anywhere from 4.0 to 4.2 with my 115gr boolits for range use.

 

[Jack Ryan]

I seat all the bullets and then come back and crimp. I don't do both in one operation.

I use a 6" scale as a straight edge againts the wall and hold the shell up to the light to see the belling of the mouth when expanding and again after seating a bullet and setting the crimper to see the amount of crimp it's putting on it.

 

[NIFT]

I seat all the bullets and then come back and crimp. I don't do both in one operation.

Likewise; however, good seating-and-crimping (taper crimp) dies can do both in one operation, if done properly.

In my opinion, to get the proper crimp on 9mm, .40, .45 ACP and other similar semi-auto handgun cartridges, you need a dial (or digital) caliper and some good factory ammo.

Using the knife-edge end of the caliper, carefully measure the outside diameter of the very end of the case mouths of a few rounds of factory ammo to determine exactly how much crimp to apply.

Then, using the crimping (or seating-crimping) die, carefully "sneak up" on the correct amount of crimp by gradually adjusting the die down until you measure the exact same outside diameter of your finished case ends as you got on the factory ammo.

If you are using a seating-crimping die and start to notice bullets being shaved, then you may want to do two operations: seating and then crimping.

Hope this is some help!

 

[rvb]

For a round like 9mm that headspaces off the case mouth, all the "crimp" should do is remove any belling you introduce prior to seating the bullet.

If you are using only one headstamp brass, bullet dia + 2x(case thickness) is your crimp measurement.

two quick ways to set crimp...
-I set my crimp so that I can put a strait edge on the side of the bullet and with a light behind it not see any belling left.
-I measure the cartridge dia at near the base of the bullet, middle, and case mouth, and target getting the measurements to match.

I then pull a few bullets and look for crimp rings on the bullet. Sometimes, esp when loading mixed brass and checking cases with thicker walls, you'll see just a small ring on the bullet, but you don't want to be able to feel it. This is especially important if you are seating/crimping in one step to check for bullet shaving or damage to the jacket.

If you over crimp, thinking you are holding the bullet tighter, you may actually be doing the opposite. As you taper crimp in the mouth, it could cause the case to bulge out below the mouth and reduce tension on the bullet. Bullet tension is all accomplished in the sizing. Take a loaded round and push the bullet against a something solid and measure to see if you can push it back (and then I like to load it 5 times in my gun and measure for set back. You might see 0.010 after 5x depending on gun, but more than that and you may have a tension issue).

-rvb

 

[Leadeye]

I have had good luck with Redding taper crimp dies on cases that headspace on the mouth.

 

[zenbruno]

RVB, that is one of the best and most helpful descriptions of cartridge crimping, for straight-wall calibers like the 9mm, that I've ever seen. I learned something, too. I like the formula for determining crimp measurement (or, more specifically, for eliminating "bell"): bullet diameter + twice the case-wall thickness.

Good stuff!



Cheers!

 

[Bob.]

For a round like 9mm that headspaces off the case mouth, all the "crimp" should do is remove any belling you introduce prior to seating the bullet.

If you are using only one headstamp brass, bullet dia + 2x(case thickness) is your crimp measurement.

-rvb

Thats a great explanation !
A lot of people think there has to be a actual crimp in to the bullet.
I pulled these from a batch that a friend reloaded because there was a serious accuracy problem.
Didn't take long to figure it out !

Bob.

 

[Josh Ward]

+1 for rvb

all you want to do with 9mm, 40, 45 ect is take out the belling.....

 

[Aszerigan]

You're learning, young Jedi. You're doing great so far! Remember, always learning. I am too.

I recently had some ammo that I didn't taper enough - causing loading problems. There's a fine line between not enough and 'just right.'

 

[malern28us]

If I can remember, I will post a pic of the first "bell" I put on my .40 case. It is worth a chuckle.

 

[NIFT]

RVB, that is one of the best and most helpful descriptions of cartridge crimping, for straight-wall calibers like the 9mm, that I've ever seen. I learned something, too. I like the formula for determining crimp measurement (or, more specifically, for eliminating "bell"): bullet diameter + twice the case-wall thickness.

Good stuff!



Cheers!

Minor point: the 9mm is not straight cased. The case has a slight taper to it.

 

[aetucker1]

I'm sort of new to reloading as well...and I thought that I read somewhere that a crimp isn't really necessary for larger caliber pistol (ie. .45). Am I crazy?

 

[Aszerigan]

I'm sort of new to reloading as well...and I thought that I read somewhere that a crimp isn't really necessary for larger caliber pistol (ie. .45). Am I crazy?

Yep, crazy. Believe it or not, a crimp on a .45 is MORE important than on a 9mm to ensure proper feeding into the chamber.

Also, its good practice to crimp all pistol ammo. It keeps the rounds to their proper OAL longer in the chamber, mag or cylinder - any basic reloading manual will tell you this. Over crimping will affect accuracy, but non-crimping can affect functionality.

 

[billybob44]

My that looks familiar! I did the same thing on more than one occasion myself! I also learned how not to flare a case! I could have probably put a .40 in my first 9mm case that I flared!

BTW...that looks like a great load for general purpose 9mm. I like anywhere from 4.0 to 4.2 with my 115gr boolits for range use.

If you want a GOOD flare, put a .357 case into an expander die that's adjusted for the .38Spl.---Ask me how I know---------Bill..

 

[billybob44]

I'm sort of new to reloading as well...and I thought that I read somewhere that a crimp isn't really necessary for larger caliber pistol (ie. .45). Am I crazy?

+1 on a good crimp on all handgun ammo. Also on the mag. loads, a firm roll crimp is needed to build pressure for a complete burn of the slower burning powders (WW-296+H-110 for example.)

 

[NIFT]

I'm sort of new to reloading as well...and I thought that I read somewhere that a crimp isn't really necessary for larger caliber pistol (ie. .45). Am I crazy?

Naw, not crazy--just asking good questions!

Every pistol cartridge requires some sort of crimp, because the case mouth is flared during the reloading process to accomodate a new bullet. Therefore, the case has to be turned back in to some degree. Semi-auto rounds (9mm, .40, and .45 ACP) headspace on the case mouth; so, the final diameter (crimp) of the case mouth is a critical dimension.

Revolver cartridges headspace on the case rim, but they are still crimped to turn in the reloading flare and to hold the bullet tight, especially when shooting "magnum" loads.

Rifle ammunition, typically, does not require a crimp, because the case is not flared in the reloading process. However, some rifle ammo is crimped to hold the bullet tighter in hard recoiling semi-auto rifles. Additionally, military ammo is, typically, crimped both at the case mouth (bullet) and the primer pocket to ensure nothing comes loose in rough handling.

Hope this helps a bit.

 

[JoshuaW]

My that looks familiar! I did the same thing on more than one occasion myself! I also learned how not to flare a case! I could have probably put a .40 in my first 9mm case that I flared!

BTW...that looks like a great load for general purpose 9mm. I like anywhere from 4.0 to 4.2 with my 115gr boolits for range use.

Never had a problem with crimp, but flaring... The first case I flared looked like a candle stick holder! I seriously flared almost half the case. I broke out the instruction books again, and have thankfully not repeated that mistake again.

 

[MikeDVB]

Nah, not enough... More next time.

 

[Fullmag]

Nah, not enough... More next time.

...and a little more and little more. Did that on some 45's a couple weeks ago...yep, they where crimped alright and then some.