Qustions about my 44 mag

[aspenband]

So I picked up a used H&R 44 mag with 16 inch barrel and red dot scope. A few days later I found a great deal on 2 barrels one 20 ga slug with rifle sights and the other a survivor .410/45 colt. I had to do some fitting with the 2 new barrels but they now lock up tight and head spacing check shows them to be good. With all the reading I am doing on here I can't seem to find a direct answer to 2 of my questions. 
The first has to do with the frame which is stamped SB2 357 magnum 44 magnum and shotgun barrels only.  So when the 44 magnum operates at 36,000 cup why is it not safe to add other low pressure load barrels to this receiver, one example would be 45-70 which operates at 28,000 cup.
Next has to do with the survivor barrel, is it safe to shoot core bon and buffalo bore +P 45 colt loads from the barrel or because it is a shotgun barrel should I stick with standard loads at 15,000 cup.

[gendoc]

several reasons.......you need to read tha FAQ's in tha sticky's above...........
case head diameter and barrel steel quality are justa few things

[aspenband]

I read the faq and have searched past posts yet did not find a reason for my question about the addition of other low pressure load barrels being fitted to the frame.  The frame can safely handle 36,000 cup pressure that is produced by the 44 magnum, and the barrel steel of both a 44 magnum and 45-70 are the same yet the 45-70 loaded to saami is only producing 28,000 cup.  In the past H&R produced 45-70, 30-30 and 22 hornet barrels for cast frames in addition to 44 mag and 357 mag which all adds to my confusion on why they can't be placed on the current SB1 frames (I do realize that despite it being stamped SB2 it is really just an SB1 frame on this weapon).
As for the barrel on the .410/45 I understand that is is a different weaker steel, my search in past posts show many people using core bon and Buffalo bore bullets as well as some high pressure reloads without any kind of failures but that doesn't seem like a good idea to me which is why I asked that question.

[gendoc]

one cannot compare operating pressures between calibers due to case head diameter differences.
and the 45/410 barrel is made of shotgun steel capable of not much more than 14.4k pressures
i would not want to be look'n down that barrel with higher possibilities, but thats me.

[aspenband]

Ok thanks, can someone explain how case head diameter effects the operating pressures in relation to frame stability?

[quickdtoo]

Bolt thrust, or breech thrust in this application is dependent on pressure and the inside area of the case head. Please don't confuse  CUP and PSI, they aren't the same except is some applications, the SAAMI MAP for the 44mag is 36kpsi, not kcup.

Tim

http://www.riflebarrels.com/articles/custom_actions/bolt_lug_strength.htm

http://www.leverguns.com/articles/saami_pressures.htm

[nanuk-O-dah-Nort]

So I picked up a used H&R 44 mag with 16 inch barrel ...
.....the frame which is stamped SB2 357 magnum 44 magnum and shotgun barrels only.  So when the 44 magnum operates at 36,000 cup why is it not safe to add other low pressure load barrels to this receiver, one example would be 45-70 which operates at 28,000 cup....
Next has to do with the survivor barrel, is it safe to shoot core bon and buffalo bore  P 45 colt loads from the barrel or because it is a shotgun barrel should I stick with standard loads at 15,000 cup.

some clarification is needed please.

does the RECEIVER have the stamp SB2? or the barrel?
you can pull the buttstock off and check the frame, as per FAQ to make sure.
You need to KNOW which receiver you have!!
====
when considering pressures and breech thrust, I use the maximum diameter of the case head, NOT THE RIM, which builds in some safety margin.

then it is a matter of Math.  I made up an excel spreadsheet to assist me. I just punch in the numbers.

another important thing is the Firing Pin diameter.  if it is the larger pin, you may encounter difficulty with higher pressure rounds.

====

I think some custom reloaded rounds, such as CorBon, are operating on the ragged edge of max pressure.    Even some 45/70 loads are HOT!  not all factory 45/70's are at the lower SAAMI pressures.  (although they should be labeled, it is important to remember)
I think the custom loaders even tell you WHICH GUNS they recommend to shoot their stuff, and recommend you do NOT shoot it out of anything else.

====

Because of your questions, and they direction they are leading, I'd suggest you stick to H&R specs, don't shoot the high pressure stuff, and don't fit a barrel that can shoot any high pressure factory stuff.  ( I don't include CorBon et al in this as they are specialty, and no one should shoot them unless they understand their guns)

IF H&R says you are good to go, then fine..   BUT another gun in proper caliber is not that expensive and surely better than wrecking one you have because you didn't fully understand what was happening.

read LOTS on the subject, there is literally thousands of hours worth on the internet from REPUTABLE sources, and not hearsay like what I am telling you.   After all I too am still learning!

once you grasp the basics and intermediates, you will find the complicated stuff not so bad.

in the mean time, stay safe and shoot often!

and remember, very large animals were nearly killed off to extinction with some low pressure rounds throwing middle of the weight range lead.

[aspenband]

Thank you!  Best explaination so far.  I guess I should have clarified that I have no intent of not following recomendations set by H&R/NEF on any receiver or barrel.  My intent was strictly for knowedge as it wasn't making sense to me and so many people on here are overloading their guns.  I am very happy with my current set up and don't need hot rounds for the 45 Colt as I have the 44 mag which will do everything I want from this set up (it was also cool because I already own a ruger super blackhawk 44 magnum).  I do intend to buy a new, or used SB2 in the near future for more powerfull cartridges. I bought this one as a truck/ATV gun for fast short range shooting, might use it for Javalina here in Arizona just to say I did it.  Sticking to my 2 remington 700's in 25-06 and 30-06 for most of my hunting.

[gcrank1]

Good for you, inquiring minds WANT to know!
I dont think 'many' here are overloading their guns, though some have and a few still may be, and at least one has had a disaster in spite of the warnings and admonitions posted by MANY here.
You will get some of the best, most level headed, and gentlemanly responses on these forums of anywhere, so dont fear posting questions as we all started with these silly things somewhere. In many ways we are like a bunch down at the fire after a good day on the range, so grab a cuppa and talk loadin', shootin', and whatiffn'  .