I'm still around Gatsby, though my continuing middle eastern 'vacation' makes internet access sporadic to say the least!

First of all, I think Bigdog could probably teach me a thing or two about recoil judging by some of the crazy guns he shoots, but I'll throw in my recoil perspective from shooting my 4.

-With heavy loads it leave a bruise, every time, even with a shoulder recoil pad.
-If I didn't focus on it, my right hand middle finger would get battered to the point it would swell and remain painful for a week or so afterwards. I started wrapping the rear of the trigger guard with bubble wrap until I improved a bit.
-I usually shoot 3-4 rounds, with 5-10 minutes between to collect my thoughts, but have quit after one when things didn't feel right. The most I've fired in a day was eight light-medium loads. I try to quit before any sign of 'gun headache' occurs, as who knows what damage you may really be doing.
-After every shot I promise myself I'll never do that again! The feeling passes and in a few minutes I'm grinning like an idiot and back at it.
-It's brutal and a hoot too, and I think it has improved my shooting by forcing me to really really focus every ounce of my mind on the shot and follow through while rolling with the punch. It reminds me of when I used to box. I had to convince myself that getting punched in the face (repeatedly in my case, I was terrible) wasn't a good excuse for not doing what I set out to do. Misses hurt as much as hits.

Now that my rant is out of the way, what exactly do you have in mind Bigdog? I assume a muzzle loader? Giles Whittome in the UK is finishing a cartridge single 2 bore (1.052" diameter, proved as a 2 bore, as there is a bit of license in bore guns) currently. I don't know if he would make anything larger. He penned an article in DGJ 2-3 years back regarding his efforts and the proofing process. His guns are first class. Ross Seyfried has a 600N single shot of his that was in Rifle magazine 6-7 years ago and he made an incredible 44" damascus 4 gauge barrel for my Bland several decades ago.

I don't recall who made John the Greek's muzzle loading 8 bore, but I recall he mentioned the maker also made 4's. It looks like an outstanding gun and maybe he could be persuaded to go big(ger)?

Are you after a 1.350" bore? I cringe at the thought of how heavy and brutal that gun would be, but I understand, I have the fever too

Bob