Ron IL
Bearcat
Recently I saw on a forum the discussion about where to crimp a 38 spl DEWC (double ended wad cutter). I emailed a bullet company and they said it didn't matter. You could crimp it on the end or in the first groove. They didn't think it affected anything. So I decided to find out. I used a Ruger GP100 4" for the test. I reamed the cylinder holes to be sure they were the same. Cases tumbled in corn cob media and used all GFL cases. Each load was weighed on my Dillon balance beam scale. I used 148 grain DEWC coated bullets from Mastercast Bullets, which is a local company. I used a Lee Classic 4 hole turret with the 4 die carbide die set. Nothing changed in the die setting except where the bullet was crimped. Each test consisted of 12 rounds each. It is a short test but was for my information only. But I thought I would share what I found out. I used 231 powder. I did not weigh each bullet or check case lengths of empty brass. If I were doing competition I would do those things. This is just range pickup brass and loaded for plinking.
First test was 3.8 grains of 231 in both crimps.
Bullet crimped at groove: Hi 838 fps, Low 773 fps. Difference of 65 fps Ave 809.4 fps
Bullet crimped on end: Hi 887 fps, Low 862 fps. Difference of 25 fps Ave 874 fps.
It seems from this short test that the crimp on end was more consistant. May have to do more on this.
Second test I added some extra powder to the groove crimp round to get the fps up to the end crimped one.
Bullet crimped at groove 4.1 grains of 231. Hi 890 fps Low 856 fps. Difference of 34 fps. Ave 874.75 fps
Bullet crimped on end 3.8 grains of 231 Hi 896 fps Low 856 fps Difference of 40 fps. Ave 874.66 fps
This shows there is a difference on where you crimp because of the space inside of the case. I don't have any way to see what pressure is doing and your gun may like them crimped longer or short for accuracy. But you can adjust the speed with powder.
First test was 3.8 grains of 231 in both crimps.
Bullet crimped at groove: Hi 838 fps, Low 773 fps. Difference of 65 fps Ave 809.4 fps
Bullet crimped on end: Hi 887 fps, Low 862 fps. Difference of 25 fps Ave 874 fps.
It seems from this short test that the crimp on end was more consistant. May have to do more on this.
Second test I added some extra powder to the groove crimp round to get the fps up to the end crimped one.
Bullet crimped at groove 4.1 grains of 231. Hi 890 fps Low 856 fps. Difference of 34 fps. Ave 874.75 fps
Bullet crimped on end 3.8 grains of 231 Hi 896 fps Low 856 fps Difference of 40 fps. Ave 874.66 fps
This shows there is a difference on where you crimp because of the space inside of the case. I don't have any way to see what pressure is doing and your gun may like them crimped longer or short for accuracy. But you can adjust the speed with powder.