Older 158 sb1 vs newer sb1

[gjdykeman]

I have a 1970 Topper Model 158 frame I have recently purchased. It came on a 12g with a red recoil pad. The frame has a rebounding hammer and a small fireing pin. I have two other sb1 frames with transfer bar and large firing pin. One is on my 45/70 muzzleloader. I plan to keep that one there. Shotgun primers. The other is on my pistol cal barrels. I have three I switch. Is there any advantage to the 158 frame in this configuration? I am contemplating using the 158 frame with the pistol barrels.

[petemi]

I'm no where near the expert Tim is, but I think the small firing pin would make it perfect for pistol calibers.  I'm sure Tim will be along to correct or expand on this.

Pete

[cudatruck]

IF you have been using the pistol calibers they way you want to on your sb1 shotgun frame with the large pin and have had no problems I don't see why you couldn't keep on doin it. I would consider that lucky after the problems i had with mine.
you have been shooting three different pistol calibers on this one frame with large pin and no problems? Full power loads? factory ammo? no primer piercing or primer metal flowing back around and into the firing pin hole? no difficulty opening action after firing? If so that is way cool. Sadly not my experience.

[quickdtoo]

While the M158 frame isn't an SB1, it is cast iron similar to an SB1, if it has a small rifle size firing pin, which I think all did, it should work fine with low pressure  chamberings, the M158 was factory available with Hornet, Jet, 357mag and 30-30 barrels. The similar M155 Shikari was available as a 44mag and 45-70, and I believe H&R Inc fitted the M158 frames with those two accessory barrels as well.

Tim

[Trophy Tom]

What's the diameter of a large firing pin
Vs a small firing pin. 
And I have a. 357 mag barrel with a standard head
Forearm screw. And a 44 mag with a Phillips head forearm
Screw. Both just say H&R then the caliber on top of the barrel They are different
Thread sizes.  When did H&R change the screw. Year ?


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[gjdykeman]

Thanks guys, I shoot a 45lc with heavy bullets, 340g gc over a generous amount of w296. Same load out of the blackhawk also. Never had an issue. 41 mag 225g plated hollow point, same powder and 45acp, normal auto loads. The firing pin hole is very small, like an sb2. The others are at least twice as big. The rebounding hammer was part of the question, any Advantage?To

[quickdtoo]

Rebounding hammer isn't as safe, if it slips out from under your thumb when cocking it can discharge, a modern transfer bar won't unless the trigger is pulled, so no advantage other than less mechanicals to break.

Small firing pins are around .060", shotgun pins range up to around .090" and bigger, it's not the pin size, but the bigger hole in the standing breech for it that allows primer flow on shotgun frames. Dunno about the forend screw thread change, I've asked without success. The early 158 barrels were ¼-28 which my 30-30 is, later ¼-20, could have been when they changed to the high hammer and transfer bar, but I only have a barrel, no frame.

Tim

[gjdykeman]

Rebounding hammer isn't as safe, if it slips out from under your thumb when cocking it can discharge, a modern transfer bar won't unless the trigger is pulled, so no advantage other than less mechanicals to break.

Small firing pins are around .060", shotgun pins range up to around .090" and bigger, it's not the pin size, but the bigger hole in the standing breech for it that allows primer flow on shotgun frames. Dunno about the forend screw thread change, I've asked without success. The early 158 barrels were ¼-28 which my 30-30 is, later ¼-20, could have been when they changed to the high hammer and transfer bar, but I only have a barrel, no frame.

Tim

Just a note,this 158 frame does't strike the firing pin unless the trigger is pulled. I tried a number of times, letting the hammer slip and no strikes. And way lower hammer, might not need the hammer extension. The 1970 barrel that came on this frame had the older stile for arm screw.

[Doublebass73]

Just a note,this 158 frame does't strike the firing pin unless the trigger is pulled. I tried a number of times, letting the hammer slip and no strikes

I've tried this before on a Stevens 94C that I had and got the same results, no hammer strike unless the trigger is pulled.