270 WINCHESTER using H4831SC w Lee Factory Crimp
Hornady 140gn BTSP INTERLOCK - CCI PRIMER - NORMA CASES

All loads shot in BRNO ZKK600 (23" BARREL):

56.8gns AV VEL = 2905 Fps
56.5gns AV VEL = 2892 Fps
56.0gns AV VEL = 2867 Fps
55.5gns AV VEL = 2856 Fps

Using same BRNO ZKK600 with Hornady 140 Interlock 52.4gns and Vihtavouri N160 gave 2858 Fps.

Why do you use the Lee factorycrimp?

If you can avoid using it I think you should try that as well.

Habit, I suppose. It is said to give a uniform pressure curve. I would be interested in your comparison with and without it.

I have a factorycrimp for the .270, but either its too long or I havent understood how to use it. I never really tried it. My .270 win shoots very well without a crimp, especially Sierra Gamekings in 130 and 150 grain. My prefered powders is Norma MRP or Vihtavuori 160, with MRP giving best presicion and highest velocities.

For next season I'll load it with fmj's to shoot capercaillie.

If your gun shoots just as well without the crimp, it should at least improve caselife and give a bit less work reloading.

How to use Lee Factory Crimp die. Pull down handle on press so that "ram" with shellholder is at it highest position.

Screw down factory crimp die so that it contacts the top of shellholder. Turn the die down another 1/4 to 1/2 turn and lock off.

Now run loaded reounds with bullets already seated to correct OAL through the die.

Factory crimped. I use 1/4 turn only.

I think thats how I have tried to do it, but the die is to long so the case does not get crimped.

Have you tested any direct comparisations, same load with and without crimp?

enfieldsspares,
to get a more even crimp turn the case 1/4 turn once you have crimped and then crimp again, it gives a more even crimp, but in the long run your cases suffer..
If you clean the neck properly so there is no carbon fouling then you should not need to crimp to get even neck tension..
Short bullets,very short bullets may benefit from crimping, but I think that most reloading is done without..

regards
griff