SB1 44 magnum and 357

[rickt300]

I find it odd that H&R is now using the SB1 frame for the 357 and 44 magnums. Does this show the frame (SB1) is stronger than just for shotguns? What are factory level pressures for these two rounds?

[quickdtoo]

SAAMI sets the pressure standards, those are the only two rifle chambered barrels they'll fit to a '87 or later SB1 frame.

Tim

http://www.lasc.us/SAAMIMaxPressure.htm

[Troyboy]

I wonder what max pressure is for a sb1 frame. Seems like 30-30 and 45-70 would be in the ballpark as well as 45 colt and some others

[rickt300]

Factory 45-70 is pretty low pressure (28,000) and the 30-30 is at 42,000 psi and current 44 mag levels are 36,000 psi. I believe most factory ammo for the 45-70 is held to less than specs because of all the olt Trapdoor Springfields out there people still like to shoot.

[zoner]

when you run the numbers it looks like you could buy a new shotgun(with a reciever that H+R will fit to)sell the shotgun barrel in the classifieds,send the reciever in for a 357 or 44 mag barrel to be fitted,then fit a forend to that specific barrel...sounds to me like you could put a new gun together like that and when you get done not have more than 200 bucks in a new rifle....right?

[mcwoodduck]

I figured it was for the firing pin size.
Both 357 and 44 use large pistol primers and are similar in size to the insert in a 209 primer for a shot shell.
Where center fire rifle primers are smaller with a lot more pressure and with that big of a hole around a rebounding fireing pin could expand the primer metal back into the large hole and make it dificult to open the rifle after shots.

[Singleshotsam]

I agree w/ mcwoodduck on the primers. 

[rickt300]

Both large pistol primers and large rifle primers are the same diameter as in the 44 magnum and 30-06. Small pistol primers such as in the 357 are the same diameter as small rifle primers as in 22 Hornet and 223 Remington.

[quickdtoo]

I don't think primer size is the issue, primer cup thickness more than likely is tho, particularly with higher pressure chamberings. I shot my 357Maximum barrel on an SB1 frame when I first got it 5yrs ago using Dan Wesson factory ammo, on the 3rd or 4th shot I noticed that the primers on a couple of the previous rounds were perforated or real close to it. I swapped the barrel to an SB2 frame and it shot just fine with the same ammo. I'm not the first to experience this with the Max on an SB1 frame, so it wasn't just the ammo, it's most likely due to thinner primer cups with the higher pressure of the max over the mag. I couldn't find a reference showing pistol primer specs, but found this on rifle primers which vary quite a bit in thickness between manufacturers.

Tim

http://www.jamescalhoon.com/primers_and_pressure.php

[mcwoodduck]

Sorry to start the whole primer thing.
I am not always good at explaining what I mean and think everyone has the same base of referance.
A firing pin for a shot gun is huge in diameter compared with that of a standard rifle. For arguement we will say 30-06.
with that large if a pin both in width and depth it could peirce the primer and you would have gas venting back along the pin. A shotgun pin usually projects further from the frame than does a rifle pin.
But.  The two pistol rounds are low pressure compared to 30-06 and very similar to shotgun.  I load my handguns and shotguns with the same powder.  I did not mean to imply that the pistol and rifle primers were different in construction.  I do think they stamp out X million primers and fill them with different goop to get what they want in the way of spark for pistol (small and large), magnum pistol and small & large rifle.
I have had a side by side that was made originally as a rifle and a pair of 20 bore tubes was stuck on and I got it as a shotgun only.  Depending on the primers I used it would only dent some makers and not set them off as it has rifle pins.  Other primers it would stick a hole in them.  Those same primers give me no problems when shot out of another shotgun like an 870 or ruger red label (my uncle calls mine a Pink Label because it's a 20).

[gendoc]

pink label.... I LIKE THAT!!!!!!!
HE'S A WISE OL'BIRD, AIN'T HE ?
HE'S GOTTA BE COOL!!!!!!!!!!!
AND HE MUST KNOW A HELLAVA LOT!!!!!!!

[kevinsmith5]

I'm pretty sure my top end 45-70 loads would NOT be safe on my Pardner frame...primers or no primers.

[rickt300]

The firing pin on my model 29 is huge compared to the one in my Pardner frame, it also sticks way out of the frame. Speaking of revolvers they seem pretty sloppy when you consider their headspacing.  I would say that the 45-70 with factory loads would be safe in an SB1, especially one made in the late 90's. Obviously if H&R thinks the SB1 is safe using pressures up to 36,000 psi then it certainly has some usefulness. However as SBII frames are not that much more expensive why not use one.  I might maybe use an SB1 for a 22 Hornet someday. 

[petemi]

My Huntsman and .410 are on SB1 frames, everything else will always be on  SB2s.  No room for screw-ups.

Pete

[rickt300]

The old H&R put thousands of rifled barrels on what was a SBI as far as I can tell. I owned several, 22 hornet, 30-30 that never gave any trouble. The modern SBI surely has to be as good as the old H&R's.  Especially the post 1998 models.