DaleS----Since finished weight was excess, I suggest that you made barrels too thick, too heavy, a common error with Americans who are used to rifle barrels being thicker than they need to be. I strongly suggest that all conversions have firing pins bushed, regardless of the lower breech pressures or not, as proper bushings also contribute to increasing strength to rear of firing pins at breech, as found on lower strength shotgun actions. To not bush pins, and get by with it, doesn't mean that you can do it again; you are risking possibility of failure. Even W. Ellis Brown, early on, as explained in his book, made this mistake, thinking that he could get by without bushing, after previously not busing, and getting by with it, and he paid the price, an expensive stock blown to pieces, and pictured in book. I took class from him, covering the conversion process, in gunsmithing school, prior to his writing book on same subject. I sent PM, trying to answer DR build questions; hope it helps.