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I’m guessing some of you won’t even read this post, due to the sheer volume of …. I’ve been posting, but if you would please read this one and respond if you can offer any advice or thoughts.

Moving ahead on my Rossi conversion again, small gun show today (Sat) in southern Maine, had considered the larger one in southern Mass. but 4 hrs drive one way is just more than I want to deal with (though I’d be more likely to see DRs there- maybe even find a 26” brld 20ga. or 410 Rossi hammer double too), but hopefully a couple dealer friends and gunsmiths will choose staying close to home also. I spoke to my brother yesterday and he sounded enthusiastic about me coming down to visit over the Easter weekend (10-12 hrs down w/family business sidetrip, 8 hr drive return trip), spending 2 solid days out in his shop cutting off one set of barrels, reaming, tapping and facing the monoblock, turning barrel stubs for fits and thds, also turning 2 or 3 rings for the breech face, roughing out a new extractor plate, and time permitting machining a ¼ rib & spacers – basically preparing for tinning and then soldering barrels to block sometime after I return home! If all goes well at the gunshow today I’ll make the contact for having my 30 cal contoured blanks short chambered next week, and now that the weather’s starting to warm up a little (no more subzero nights!) then dig through my still packed away tooling for steel, expansion reamer and taps, etc. – whatever I’ll need that my brother won’t have in his small home shop.

If I accomplish enough down in NJ in 4 wks over the Easter weekend I’m hoping after I return home to get the barrels tinned, assembled and soldered up to the monoblock (along with the ¼ rib), and a neighbor with a welding shop has a vertical mill I can use for fitting up my rebuilt extractor and then back to my gunsmith buddy for final chamber reaming for headspace. Once everything’s cleaned up I guess it’s time to proof and will build a secure base for same, just hoping I can remove buttstock and reassemble both hammer sidelocks and trigger assy sans wood! I’ll post more progress reports (and some pictures too!) after my machining trip to NJ, but now for a couple questions regarding choice of cartridge.

Since I’m carrying my 2 30cal brls with me to the gunshow, in the hopes that the same gunsmith who rechambered my H&R/NEF singleshot from 30-30 to 30-40 will have a table there, and will be confident that his reamer is sharp enough to cut a couple chambers. I’d previously posted the following: “…just got a bargain purchase on 2 new 26” .30 caliber profiled blanks - $125- for the pair … to end up 25 or 26” 30-30 or 30-40 Krag barrels fitted to my Rossi 20ga monoblock, w/a ¾-16 thd’d and .700” dia. sweat fit per Ellis Brown leaving a barrel/chamber min. wall thkness of .140” in 30-30 and .120” in 30-40, with monoblock wall thkness adding another min. of .150” all around at breech – resulting in a “receiver” 2.5” long and 1” O.D. On the surface this sounds adequate, but the monoblock remaining wall thickness of .150” doesn’t take into account thd depth (down to .125” at thd crest), and the wild card till I cut off the barrels and expansion ream both chambers to a true cylinder – will the furnace brazed in the monoblock shotgun barrel stub (which will then remain a thin furnace brazed sleeve in the block) provide adequate strength after barrels are tinned, screwed down and properly sweated? My gut instincts tell me that if the factory furnace brazing was done properly, and if I fit and sweat properly, yes! Thoughts, am I missing something, or being too self-assured?” My other options, as I perceive them now, are to chamber to 30-30 (ANSI/SAAMI 42,000psi) which due to the smaller base dia, would gain me .015-.020” thicker chamber walln and due to smaller base dia., lowered backthrust. For comparison, since 30-40 (ANSI/SAAMI 40,000cup) converts (APPROX.!) to 42,5000psi and acknowledging increased backthrust with less than a 10% increase in base dia over 30-30, I feel that for my use 30-40 downloaded to 30-30 vel/energy levels for lower pressure normal use is still a prudent choice, and will permit occasional use of 30-40 factory ammo. I was tempted to fit up my 45 cal blanks since I really would like a 45-90 (or better yet 50-110!) instead of the 30 cal’s, but 45-90 would further thin chamber wall by an additional .020” and base dia. by an additional 10% over 30-40 – getting a little to marginal on the 20ga frame without knowing if it will even handle a 32-40!

I realize that the “proof of the pudding” will be in proof firing and I’ll hold off on questions regarding critical measurements before and after proof, and proof loads till I have barrels installed. If my Rossi 20ga outside hammer survives as hoped, I’ll finish ribs, etc, fit 20ga barrels (refitting both barrel sets w/new hinge pin), rust blue, and build fitted compartment for one of my hard cases – and enjoy shooting it! Then we’ll attack a larger 12ga for that 45-90 (or 50-110), or if the right shotguns show up, the possible 410 w/45 Colt barrel set. I’m thinking positive and hoping I’m right, but it’ll probably be another 60+ days before I’m ready to proof.

Thank You, Joe (hobbyguymaine)

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