50BMG and amount of crimp????

[alpha6164]

I got the Hornady 50BMG kit and have prepared some cases and ready to load and assemble. I am having a difficulty figuring out the amount of crimp to put on the bullet. The ammo will be fired in a Barrett M82 so it will be a semi of course and would require a crimp.

The way i set up the seater/crimp die is as follows:

1) Insert empty case in shell holder and move ram to highest position
2) Unscrew the seater screw all the way up and thread the die body all the way until it touches the empty brass.
3) Unscrew the die body two turns per Hornady instruction
4)Insert a bullet and adjust the seater die until u to desired length.
5) Then turn the die body 1/8-1/4 turn clock wise until desired crimp is achieved and adjust seater die as needed.


My issue is that the 50 BMG brass is so thick and heavy that it is very difficult for me to differentiate changes in crimp as i thread the die body in further increasing crimp. Can anybody tell me after the die has touched the empty brass do you turn in/out the die to achieve a crimp for a semi auto? Thanks.

 

[nofishbob]

In order to increase crimp, turn the die in (clockwise).

Remember to back off your seater adjustment prior to this or you will end up with the bullets seated too deep as you lower the die.

After you get the crimp dialed in, turn the seater in slowly until you feel it touch the bullet.

Hope this helps!

Bob

 

[alpha6164]

^^^I definitely understand that part. What i am trying to figure out is actually how much crimp to apply?

 

[rg1]

It's a lot easier to crimp in a second step. I adjust my seating die down until the crimp area of the die touches the case mouth, back it back away about 1/8 turn and seat all bullets. Then after all rounds are loaded I back the seating stem way back and readjust the die for crimping. If your bullets have a cannelure, all cases are trimmed as close as possible to the same length, adjust your die for crimping so that the inside of the case mouth will touch the ridges of the cannelure. No need to press the case mouth into the ridges of the cannelure. I bring the die down to touch the case mouth, turn it just slightly in, crimp and then look closely at the inside edge of the case mouth. If I can still see that there is a little gap between brass and bullet I'll turn the die in just a little more. When I can see there is no gap I lock the die at that point and crimp all the loaded rounds. No need for a heavy crimp digging into the bullet. Not scientific but works for me. With military or some factory brass they will still have some of a factory crimp left after you trim. That will make perfection harder as the factory crimp deforms the case mouth and the crimp marks left will make the mouth not uniform and the die will not crimp exactly the same on each case. You can seat and crimp in one step if you choose. The big 50 case isn't quite as easy to crimp as smaller cases. Military surplus bullets are most often not made in the same lot and cannelure shapes can vary too. No need to over crimp but just turn the case mouth in to just touch the cannelure ridges.

 

[rg1]

To adjust your dies for seating and crimping in one operation, adjust the die down on a empty case until the crimp area just touches the case. Back the die away from the case about 1/8 turn. Adjust your seating stem and seat a bullet to the desired overall length (without any crimp). Then back your seater stem out several turns away from the bullet. Now turn the die back into the press until the crimp area touches the case mouth of the loaded round. Very slightly turn the die in towards the case and crimp. Readjust the die in or out to obtain the crimp you want. After your die is adjusted to crimp, lock the die lock ring. Now with your loaded and crimped round, turn the seater stem back towards the bullet until it makes firm contact with the bullet. Lock the seating stem nut. Now when the next bullet is seated it should seat to the desired length and crimp in the same operation. Recheck your overall length. You may have to readjust the seating stem a few thousandths for the exact overall length.