If a thicker barrel with more material over the brass will give you more peace of mind you may want to consider the SIERRA VISTA kit, designed for folks who do snakeskin to allow for more material. You can also buy some other kits with thicker material(s) already on the brass tubes or buy just the kit and use/make your own blank.
Here is one good source, I am sure there are other though:
http://www.arizonasilhouette.com/New_Pen_Kits.htm