Off-center cavity on Foster-type slugs: affecting accuracy?

[Y-man]

Hi,

I have been doing some casting of Foster-type slugs, and usually, I drill out the cavities. Previously: I would use an 8mm bit, and I got relatively aligned (Centralized) cavities. The slugs are less than bore (.696")

http://www.flickr.com/photos/44877118@N04/4503442845/

I now did some new with a 10mm bit (to get a bigger cavity) and quite a few of them now have cavities that are not exactly centralized: some of them a little to one side. So the skirt is thicker on one side versus the other.

http://www.flickr.com/photos/44877118@N04/4530640689/

I have not loaded, or tested yet: neither the 8mm nor the 10mm cavity slugs.

What do you all think? Do you think the off-center cavities would affect the stability of slugs in flight, thus affecting accuracy negatively? Do you think a thicker skirt on one side could cause tumbling?

Your opinion and advice would be much appreciated.

[longbow]

Y-man:

I suspect that the uneven base, short bearing length and off center cavity will result in poor accuracy.

The only way to be sure is to try some but I am betting they will not be very accurate.

For ranges of out to 50 yards or a little better, a round ball will shoot very well if a tight fit into a shotcup or tight bore size. They are easier and faster to make than hollow base slugs as well.

As mentioned in other posts, I have not had good success with any hollow base design (not saying it can't be done but I can't do it) so am working on solid designs with attached wad.

I suspect that some of my inaccuracy with hollow base slugs is due to shooting them from 2 3/4" hulls in a 3" chamber. The jump to the forcing cone and the forcing cone itself seem to result in problems. Even bore size round balls show some rotation entering the barrel as the swaged flat around the equater is sometines uneven on recovered slugs.

Not sure if your slugs are sized to fit into shotcups or not but in my experience so far with my guns, loads, etc. I have found that hollow base slugs in shotcups tend to perform better than bore size. Again, I suspect it is a forcing cone alignment issue.

SluggerDoug posted an excellent write up of how he managed to get Lyman Fosters to shoot well. You may find it if you do a search.

Several people have posted good results using the Lyman sabot slug and Lee drive key slugs from smoothbores. Might be helpful to search for those posts as well.

Good luck.

Longbow

[Y-man]

@ Longbow,

Thanks for the pointers. I will be putting the slugs into the wad (Not cutting off the petals.) So I believe the shotwad would help until it all emerges from muzzle? (So minimised cocking of the slug against the forcing cone...

Then the uneven base: it is sitting in the plastic shotwad, it will be patched (Cross-patching.) and will sit on a felt wad, INSIDE the plastic shot wad.

I may not be able to re-crimp: but will use the plastic overshot wad to hold down the slug for good resistance. (Will use glue to hold that.)

I'm getting some ammo this weekend (There has been a strange shortage recently: maybe because of the impending elections and the usual accompanying violence...) so I'll test and let y'all know...

Cheers.