Home Forums Hunting & Shooting Single Shots H&R SB1 pressure limit ??

Have an SB1 in .30-30 that I'd love to have re-bored to .375 Win.

Is the SB1 receiver capable of handling the extra 13000 psi ??

Thanks for any input !!

They did chamber them in .308W, had one for a short time.
Don't see any obvious problem for you.

EDIT: I stand corrected! What I owned in .308 was a SB2. My apologies for giving misinformation.

I believe the .308 was only done in the SB2 frame

Correct

No. Too much pressure and rear bolt/face thrust for an SB1.

Is my recollection that the SB1 had a shotgun firing pin correct?

So, I guess it was a good idea while it lasted........

Thanks for the knowledge transfer, fellers !!!!

There's still a good many H&R's out there to
be had that will be better for what you want to do.
You'll probably want to wait until the hunting
seasons are over to get a better price

You might want to keep an eye on the H&R classifieds on the Graybeard Outdoors forum. Lots of for sale items come up. Unfortunately, they are not cheap these days.

Normally yes. But I have a bunch of pre SB1 actions that all have small firing pins, but they were mostly 20 gauges. So I've never fully figured it all out.

To expand since many people, me included, use the term SB1 incorrectly. I tend to group all ductile iron framed H&Rs together and that isn't correct.

H&R Inc never made SB1 frames, NEF started making SB1 and SB2 frames in 1987 after H&R Inc went out of business in 1986. H&R Inc frames were ductile cast iron similar to SB1 though, neither were heat treated. The general consensus is since the M155 Shikari was offered from the factory in 45-70, the ductile cast iron SB1 frame should be suitable for 45-70 trapdoor loads or 30-30 so that helps a bit with limits. It's not just the chamber pressure, its that along with the "bolt" thrust.

You should be able to pick up a SB2 action for around $125ish to make this project work out for you.

Get an SB2 frame DO NOT use the SB1 frame!!

No one really knows the pressure limits of the SB1 frame, but that's not the only concern. Most SB1s have a larger diameter firing pin and some higher pressure cartridges can cause the primer to flow into the FP hole. This problem causes the action and barrel to lock together. I've seen where someone had to knock the receiver pins apart to separate them.

I'd be a buyer of your 30-30 barrel if we could agree on a decent price.

Yoder I sent you a pm

I'm curious if your 30-30 had an alpha numeric serial number, such as AZ123446789. If so, can you tell me what the first two or three alpha numbers are? That will tell me if you have a SB1 or pre SB1 receiver.

The gun is an H&R 058

SN AZ5xxxxx

AZ should make it a 1985 manufacturer date.

So........... Here's a theoretical "Part 2" to my question........

If I did get it re-bored/chambered to .375 Win (I have the brass) or .38-55 Win and used .38-55 data....or ".38-55 +P" data, I should be good to go.

Right ??

Few things.

That barrel is fine for either rebore. The current action is not ok. That action is ok for 38-55, but not 375 Winchester.

The 375 Win with a 55k PSI is the same as a 308 win. The 38-55 is at 35k PSI, the same as a 357 Mag.

You could put the rebored barrel on a SB2 and then you could shoot either cartridge.

That date code on your current action of 1985 is pre-sb1. That action most likely has a small firing pin on for low pressure of 30-30 and lower cartridges. The common rifle rounds on these pre SB1 type actions is 22 Hornet, 30-30, 357 Mag and 44 Mag and Trapdoor level 45-70.

However as for a rebore I think you have other options. I think you would be better off getting a new barrel blank and a spare cheep shotgun blank for parts and having the parts cut off and TIG welded onto the new barrel. You will end up with a MUCH better barrel and more accurate rifle. It will cost more, but perhaps not that much more. I can recommend an excellent gun smith in ID to do this. He has done some custom H&R stuff for me and us currently going to rework an old Falling Block rifle for me.

You could then sell the 30-30 barrel or whole rifle to reduce your cost. The H&R 30-30 is normally the most accurate of the H&R rifles and the rifles tend to bring a good price, however a good bit less than the premium price for 357 rifles.

Hope this helps and that you have a great Thanksgiving.

Surely do appreciate all the insight, sir !!!

I'm not sure how much buying and swapping and TIG welding I really wanna get into as I very rarely hunt with a rifle. This gun is a straight-wristed stock (which I love), a GREAT trigger and is just SO freakin' quick and handy !! And, as accurate as this .30-30 barrel seems to be with the small amount of monkeying I've done with factory loads, I probably SHOULD just leave well enough alone. But, then again......... what's the fun in THAT ??

I was actually looking through some SAAMI pdf's last night for other reasons and (surprised me !!) found that the .348 Win runs at 2K psi less than the .30-30 Win. More danged food for thought.........

Would the furniture from my gun interchange on to an SB2 receiver ??

A very happy Thanksgiving to you and yours, as well, sir !!!