downzero Posted June 1, 2003 Share Posted June 1, 2003 I've got load data for the .38 super, but no crimp information. Can anyone supply a crimp measurement for me? Link to comment Share on other sites More sharing options...
Steve Anderson Posted June 1, 2003 Share Posted June 1, 2003 Two methods: Measure the rim after it comes out of the sizing die. Bell it .010 -.012 for bullet seating. Crimp it to its original diameter. or The diameter of the bullet plus the thickness of the brass on both sides. (.355 + .010 +.010) I split the difference between these two, and crimp to about .378 You will want to observe any accuracy or reliability differences as you experiment... Eric G. advocates NO crimp, and I think Brian advocates as little as possible. You're not trying to hold the bullet in with crimp, just trying to get the brass back into shape. SA Link to comment Share on other sites More sharing options...
eric nielsen Posted June 1, 2003 Share Posted June 1, 2003 I'm with Steve. .001 to .002" crimp is PLENTY with the Super. If you shoot Caspian, a good OAL is 1.250. Otherwise ask & someone will say what is good for a S_I gun. dvc - eric - a28026 Link to comment Share on other sites More sharing options...
TONY BARONE Posted June 1, 2003 Share Posted June 1, 2003 TAPER CRIMP TO NO MORE THAN .381 THEN PULL THE BULLET. THERE SHOULD BE NO MARKS ON IT FROM CRIMPING. Link to comment Share on other sites More sharing options...
Paul B Posted June 2, 2003 Share Posted June 2, 2003 The functions for crimp in a super are: 1. To allow for a cartridge profile that feeds well in your particular gun. I've seen and owned supers which would only feed reliably withe a slightly tighter criimp i.e. .378 or a little less. It was just a function of the chamber and the feeding angles to allow the cartridge to go in smoothly. Other guns are simply not as finicky and you can get away with less. Not all guns are perfectly chambered and most of us have to live with what we have. The .378 will usually leave a barely visible indention on the bullet if pulled. 2. With some longer magazines in certain guns you will sometimes get a bit of a nose down problem occasionally and this is usually caused by variations in length. Nothing is written in stone, but Caspians seem to like rounds a bit shorter like mentioned before at 1.250, but Paras like 1.255 and STI/SVI will often tolerate even a little longer like 1.260. Your experience may vary. In any case with the slight variation you will get from most reloaders of +.005 to -.005 you may encounter a little bit of smash into the feed ramp occassionally. A little crimp will prevent bullet setback in these situations and more consistent shot to shot performance. .378 will usually do this trick. 3. If you load slower powders that fill the case you will sometimes need a little crimp to prevent the powder from backing the bullet out. Some powders like N105 really like to be a little compressed and will give excellent accuracy and performance this way. It's what works in your gun. 4. The downside of too much crimp is poor accuracy and you can tell it in group size. Real tight and you can even get bullet tumble. My crimp is always .378-.379 and I usually get 1/2" groups at 25 yards. If I pull my bullets I can see a slight indentation. By the way all these measurments are with a taper and not a role crimp. Try a few at different settings and the feed back from the gun will tell you if they are going into the chamber slick or kind of chunking in. The target will tell you about accuracy. Good luck. Link to comment Share on other sites More sharing options...
benny hill Posted June 2, 2003 Share Posted June 2, 2003 after a quarter million rds. loaded & fired it is still crimped at .377/.378 Link to comment Share on other sites More sharing options...
SRT Driver Posted June 2, 2003 Share Posted June 2, 2003 Mine work fine @.378-.379 Link to comment Share on other sites More sharing options...
Philip Dedmon Posted June 2, 2003 Share Posted June 2, 2003 It's .378 - .379 for me. Link to comment Share on other sites More sharing options...
mrsig03 Posted May 20, 2015 Share Posted May 20, 2015 Do you know if bayou have different crimps? Bullet is at .356 and I'm crimping at .381-382. When I crimp more, accuracy goes out the window and I get a wild bullets every once in a while. No issues at .382, actually, very accurate. Much more then say, Xtremes. Any thoughts? Thanks. Link to comment Share on other sites More sharing options...
Steve RA Posted May 20, 2015 Share Posted May 20, 2015 Go with what works !!! Link to comment Share on other sites More sharing options...
Neomet Posted May 20, 2015 Share Posted May 20, 2015 What others have said. .002 crimp. Measure a loaded round behind the crimp and take off .002. Overcrimping is a buzzkill for accuracy on jacketed rounds and an absolute tumble inducer on moly projectiles like Bayou. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted May 20, 2015 Share Posted May 20, 2015 Go with what works !!! :bow: :bow: Link to comment Share on other sites More sharing options...
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