Crimping for 38 super ?

[sandrooney]

What I did was to seat the bullet (MGB 124 CMJ) then measure right below the bell. It measured .375 so I set my crimp to .375 which is basically no crimp at all. I have read where most will crimp 38 super to .377 or .378 which would be less than no crimp at all. What would be the reasoning behind using less than no crimp (.377 to .378) than just no crimp (.375) ? Wouldn't the bullet be seated at .375 either way ?

Thanks,

SR

[Shadyscott999]

Your should "crimp" to brass thickness x 2 + bullet size.

Edited May 25, 2014 by Shadyscott999

[sandrooney]

My brass thickness is .012 and my bullet size is .351 so that would be .375.

Thanks for the help, SR

[Baer45]

I just ran into the crimping problem when I switched bullets in 38Super. I have always used the push test to set my crimp and with .355 bullets I am at .273 before set

Back stops. This is the only test I trust for properly crimped ammo and came from one of Patrick Sweenys books, I think Volume 1 on the 1911 series (red cover).,,

Marine Corp

Colonial Shooting Academy

[Shadyscott999]

I just ran into the crimping problem when I switched bullets in 38Super. I have always used the push test to set my crimp and with .355 bullets I am at .273 before set

Back stops. This is the only test I trust for properly crimped ammo and came from one of Patrick Sweenys books, I think Volume 1 on the 1911 series (red cover).,,

Marine Corp

Colonial Shooting Academy

bullet set back is a sizing issue not a crimp issue.

[Baer45]

I hear where you are coming from but assuming no bell with correct dies, set back consistently happens with volume reloading because of thinner brass, different spec dies, bullets out of spec etc. if my bell is correct or non existent and I have set back doing the push test, what other way besides crimp can safely hold the bullet. Your quote I feel apples to beginners who have not mastered their bell correctly...some say a Lee Factory crimp die or a U die, etc. all correct the problem by dialing down the crimp below spec to obtain a proper hold...just my experience.....learning the push test has helped me load much more accurate ammo and the first place I look is to see if I am over belling my case....fwiw

[Justsomeguy]

Like Shady said, crimp will NOT control setback reliably. Only a properly sized case will reliably prevent setback. If you have some thin brass and an undersized bullet you will sometimes experience setback no matter what the crimp is set at. The only real solution is an undersized (or Udie) sizing die that will reduce internal case diameter to the point where no setback is possible even with thin brass and reasonably in spec bullets.

[blind bat]

My brass thickness is .012 and my bullet size is .351 so that would be .375.

Thanks for the help, SR

Double check your calipers. Standard 9mm bullets are .355" in diameter. Traditional 38 super bullets are .356 but .355" usually works fine.

[sandrooney]

I will check that out. Thanks

[Baer45]

Like Shady said, crimp will NOT control setback reliably. Only a properly sized case will reliably prevent setback. If you have some thin brass and an undersized bullet you will sometimes experience setback no matter what the crimp is set at. The only real solution is an undersized (or Udie) sizing die that will reduce internal case diameter to the point where no setback is possible even with thin brass and reasonably in spec bullets.

You are both absolutely correct! I was trying to say it the same way, just not as clearly....(public school education)

[sandrooney]

It was my caliper. It was off but it was at least consistent so all I had loaded were crimped correctly to .378 but a little long . They still work fine so no harm.

Thanks for the help.

SR