Interesting find testing Lyman slug loads

[Beaverhunter2]

Today I was doing some final testing of a load for my 24F. I was shooting the same load in new and once-fired hulls. I'd been developing loads using both but the onc that shot best was a Cheddite 3" hull with a W209 primer. They had been once-fired because I'd used the new hulls with the Cheddite primer it came with. This time I punched out some of the Ch209s and put W209s in new hulls. The once-fired hulls shot 2 1/2" to 3" 5-shot groups at 75 yards- same as during earlier testing. The new hulls were consistently 10" plus.

Interesting....

John

[kungfustyle]

It may have something to do with the crimp on the new hulls. Are they skived? Roll crimp vs fold crimp? Most 1x fired are skived and easy to apply a fold crimp. Some new shells are un-skived aka straight and somewhat more challenging to apply a good fold crimp. I don't know if that has anything do do with your out come, but a 7+ moa difference is significant. Did you try to re-shoot the new hulls after they were shot? I'm interested to see if you had the same tightening in the groups.

[Beaverhunter2]

They're skived from the factory and I'm using 8pt crimp. It fits the stack height perfectly. The hulls came from the same bag. The once-fired were used for testing this or another load with the Cheddite primer. This is the first time I actually punched out the good primer from the new hull and replaced it (as opposed to firing and then loading with the W209). I also chronographed both loads. The once-fired were at 1384fps. I only did a couple shots a few weeks ago but one was 1381 and the other 1387. Today I shot 5 of the loads with new hulls and ended up at 1312fps with ES of 39 and SD of 16. Not bad consistency in velocity but I'm thinking if the slickness of the new hull is reducing pressure it may also reduce the upset of the slug that causes the load to engage the rifling. I found a wad from a new hull down range with all the petals intact. The wads from once-fired lose all 4 petals right above the skirt driving band.

I actually expected the new hulls to shoot better. Learn something new every day!

John