Hard primers in Brown Bear 115 gr 9mm and my Sig 226.

[Jeep]

Like others my guess is that you have a worn or unduly light hammer spring. My 226, which has an 18# spring, fires Brown Bear reliably, but I'd try a 19# spring if you are having that much of an issue. The 21# factory spring can create a 12# or higher DA pull, which I think is excessive.

[pangloss]

Should you want to tune your SIG to fire Brown Bear more positively, try replacing the mainspring with at least the stock weight. The stock weight of a SIG P226 will be different depending on the P226's version of mainspring base. I believe it's 24 pounds, unless there's a plastic mainspring base in which case it'll be 21 pounds.

The factory standard mainspring weight for a newer style plastic mainspring seat is 21 lbs. For a conventional metal based (older style) mainspring seat, 24 lbs is the factory standard.

Like others my guess is that you have a worn or unduly light hammer spring. My 226, which has an 18# spring, fires Brown Bear reliably, but I'd try a 19# spring if you are having that much of an issue. The 21# factory spring can create a 12# or higher DA pull, which I think is excessive.

Thanks for pointing out the different spring weights for different vintage pistols. Mine has the plastic part, so I'm going to order the 19# and 21# springs. Hopefully the 19# will work. I think that it is most likely that the previous owner put a lighter weight spring in the pistol. The pistol shows such little signs of use, that I just can't imagine anything being worn out on it.