I have one that has been in the family for 50 years and have dated it back to 1913. The flues have thin fences and should not be subject to a steady diet of heavy loads. I recently had the gun restored by a fellow who had worked for Ithaca and he recommended no more than one ounce loads. You have what appears to be a very nice Flues, but they were not designed for heavy loads. I would not hesitate to tie up 250 in bluing by a competent gunsmith.