H&R and Pedersoli Trapdoors - Need Some Assistance

I'm an old guy who knows little about trapdoors but I want a couple of the replicas to go shooting with and don't want to invest in a piece of genuine history and then inadvertently damage it while having fun. I have purchased a Pedersoli carbine, have examined it closely and it has the square shaft for the breech block cam so my only concern with it is to keep the set screw tight so the shaft won't be free to work it's way out. I've also purchased an H&R Officer's Model and have yet to shoot it because I want to be certain I won't have any unwanted surprises with it.

I have read about filing a flat on the H&R cam shaft, drilling a seating hole, using Loc-Tite, and a few other methods that don't seem to me a good solution. I know that an original latch mechanism cannot be installed in the H&R block because it won't go in and would require extensive machining (or at least more than I want to do) to make it fit. I have read that an original complete M1884 breech block will fit the H&R receiver. Is this correct? Does it require fitting or would it be a drop in fit? I've also read about the possibility/didn't happen of Pedersoli purchasing the H&R tooling, but irrespective of that, I've read that Pedersoli parts will interchange in the H&R. I'm thinking that perhaps acquiring a Pedersoli latch mechanism and cam would be a good option, but I don't know if the parts would actually fit? Another option would be to install a complete Pedersoli breech block, but again, would it fit?

I want a permanent and reliable fix and I like the idea of installing a Pedersoli latch mechanism, or a complete Pedersoli breech block, if necessary. I would very much appreciate any insight into this that anyone may have. I've read all the posts in this section regarding the H&R trapdoors and while there is much written I did not find a post that addressed the possibility of utilizing the Pedersoli parts. If I missed it, my apology. All help appreciated. Thanks!

And one last question about the H&R ... I read somewhere that the bores were undersized and then saw other posts stating this was incorrect. Does anyone know the truth of this? I plan to shoot factory jacketed soft points because I don't get any pleasure from reloading. Thanks again.

First off, your H&R MAY be perfectly OK - back when this was a hot topic, some users said they'd never had an issue. The big thing is to keep an eye on it - the problem stems from parts working loose, which is not a sudden catastrophic event. If you check to see that your thumblatch is not loose on the shaft, you are good to go. I shot my H&R OM (#5858, so "mid-production) for several years before suffering what I'll call "automatic ejection." Not knowing at the time that there was a potential problem, I'd never looked for one, and the feel during operation will not cause a reveal - you need to actually twiddle with the parts while the block is open.

Yes, an original block intended for use in receivers over 96300 (does not have to be an 1884) will fit. Some drop in, others may require a bit of work with an oilstone. Failure to latch with an original unit is simply not possible - and the modern ammo (sans the hot loads for the 1886 Win, 1895 Marlin, and Ruger of course) is OK for the block. The H&R and Pedersoli receivers are made of "better" (more metallurgically consistant) steel than the originals.

I do not know how interchangeable the H&R and Pedersoli parts are. Pedersoli SWEARS they did NOT buy the H&R machinery, and perhaps they did not (though maybe an intermediary was involved which gave them a degree of 'technical' deniability) but the similarities are certainly there. Maybe they cloned/reverse engineered one - I do not know. I DO know that the early Pedersolis had the EXACT same issue as the H&Rs, so, you tell me. Pedersoli fixed the problem not too long after things came to a head, so they should be fine now. My only problem (and it is a personal one) is that I think their too shiny, too polished (buffed-over edges) look, with off-color case hardening, and some awkward profiles which lack the form and grace of the originals, and the comparatively sloppy fitting, just look funny, and I wouldn't want one.

I do not know about variant bore sizes in the replicas, but if you are just going to shoot factory jacketed loads, it doesn't make a bit of difference. Jacketed bullets are not the greatest choice in originals because their bores DO tend to run oversize. To say something good about the replicas, my H&R OM has shot 5/8" to 3/4" groups (one ragged hole) at 50 yards, from rest.

Thanks very much for your message. I do intend to keep an eye on both rifles and check them before firing, but I'm more confident in the Pedersoli than the H&R. As I view them, the screw in the Pedersoli has only one function and that is to keep the latch mechanism from working loose from the block. In the H&R, that small screw must also keep the cam correctly positioned. The Pedersoli has no chance of an "automatic ejection" so I feel much more comfortable with it. I'm not quite sure what I may do with the H&R. It is a really nice rifle, new in the box, but adding another dimension to this, I was just today offered a Pedersoli OM so I'm considering whether I should purchase the Pedersoli rather than bothering with investing time, effort, and money in making certain I won't have any unwanted experiences with the H&R. I've no doubt the H&R can be a fine shooting rifle, it's just a matter of which option is best and most cost effective.

When comparing the Pedersoli and H&R, I find I prefer the Pedersoli. It has a better overall fitting of the parts compared to the H&R, with fewer rounded edges and corners, and the case hardening colors look better on the Pedersoli, at least in my view.

Now I just need to make a decision. Thanks again for your input.

"...filing a flat..." Or any other like "mods" will void any remaining warrantee. You should not have to fiddle with any BNIB firearm. Even if it's a reproduction. Just buy some ammo and go shooting.
The only advantage to the Pedersoli is that that company is still in business. Remington, the last owner of H&R, has shut down H&R completely. Don't think the warrantee is honoured any more. Best you contact Remington and ask. Mind you, when H&R was still operating they stopped service for discontinued and older models.