Little (Rifle) over Big (Shotgun) or Big (Shotgun) over Little (Rifle)?

[sae8425]

This is a topic that has come up before. See:

Thread: Rifle barrel on top or bottom http://www.gboreloaded.com/forums/index.php/topic,166339.0.html 

I believe that it is ergonomically superior to have the much smaller rifle cartridge mounted over the much larger shotgun shell (and I’m apparently not alone in this thought either). This is something debated/postulated on a great many forums.

And, at the risk of being accused of speaking heresy, I contend that the main reason the combination gun configuration is almost exclusively shotgun over rife has nothing do with pressure criteria, and everything to do with the manufacturers perception of the marketplace demands.

Most would be buyers seem to predominately want affordable combo guns that resemble the classic makes of yesterday.

Gun manufacturers of that bygone era did the best they could with the materials and technologies available to them. And, working within these limitations, rifle under shotguns were (especially in the heavier calibers) the best that could be made.

Yes, there have been a few rifle over shotguns made, but most were sub .25 caliber (is the much denigrated Savage .30-30 the most powerful example ever produced?), and many older ones used lower power black powder/cordite cartridges.

But today, metallurgy is much improved compared to when drillings, cape, combo guns, etc. were developed (or even in their heyday). Using the best materials and technologies available to gunsmiths today, I believe that a safe and reliable heavier .30 caliber rifle over shotgun configuration is easily possible.
 
Don’t buy this? Well, take a look what is currently available in the market and it seems to corroborate my beliefs. Almost every manufacturer of a combination gun also produces a double (O/U) rifle. All of these manufacturers offer upper & lower barrels in .30/06 (SAMMI 60,000 psi), and .30R Blaser (CIP 59,000 psi) & some also offer 8 x 75RS (CIP 56,275 psi), and .308 (SAMMI 62,000 psi). Many of these double barrels are also interchangeable with a shotgun over rifle combination barrel.

Still not convinced? Read the manufacturers literature. Many state that all of their combination guns and double rifles are built using the same actions (the same two actions: 20 ga or 12 ga depending on rifle cartridge length to be precise). So, if this is true, and all of the actions can safely handle 60,000 psi loads in the top barrel, then there is no engineering/ballistics/pressure/safety reason that a rifle over shotgun configuration can’t be produced.

We’re being held hostage to nostalgia and I for one don’t like it one little bit! That rifle over shotgun combination guns aren’t produced today is due solely to market prejudice, rather than insufficient action strength considerations.

Why would I want a modern gun configured because of yesterday’s limitations?  I don’t! Why would I want to have a carburetor equipped car when fuel injection is available? I wouldn’t!

I’m approaching this from the ease of use and engineering aspect: you don’t (if you have any common sense) hide a little bolt (that just might need to be quickly accessed and replaced) below a huge bolt (unless you want users to curse you into eternity [or even worse, get chomped on]).

As I’ve said before, I would be willing to pay a significant premium to have a heavier .30 cal rifle over shotgun combo.

I firmly believe that such a gun is eminently possible to make, but until the few firearms manufacturers active in this area quite producing the products of yesterday for consumers clambering for more of the same, and begin to make much better use of the materials and methods now available to them, WE will be unlikely to ever have the rifle over shotgun combination's that SOME of us obviously desire.

A disgruntled combo gun lover.

Best regards,

Steve

[Drilling Man]

  Balony!  Not all actions are created equil, no matter what seel they use.  The stronger designs cost a LOT more, so a simpler style is used to keep the price down, and then other options are used to deal with the pressures.  That's the reason 412's have the rifle bbl. on the bottom...

  DM

[sae8425]

Drilling Man,

Baloney (sp?)? To exactly what that I said are you referring?

I’m not naïve enough to believe for a minute that “all actions are created equal”. I fully accept that the Savage 24 is at the very bottom end (or even below according to some) of the combination gun scale and, well, all of the others are above it.

Even though I have no way of rating these higher quality combination guns in terms of action strength/engineering design, there will (in all likelihood) be a pecking order with one brand on top and all the others in various positions below it.

Quality costs money; but, I just don’t see why it should cost many, many thousands to end up with a gun that is of a design which is no longer mainly constrained by materials, methods and knowledge! This is 2010, not 1910.

Leaving aside largely hand-built European combination guns (of which at least Hofer offers rifle over/beside shotgun combination's) for the moment, lets just consider your beloved Valmet 412.

Valmet 412’s don’t all have the rifle barrel on the bottom: they did offer O/U double rifles as well.

In regards to ‘action strength’, all I can go on is SAMMI / CIP / DEVA published pressure levels (and the fact that all guns sold must conform to at least one of these standards). The SAMMI pressure level for the .308 (of which the Valmet 412 double rifle is chambered for) is 62,000 psi. Therefore the Valmet 412 must be capable of withstanding this level of stress in the top barrel area of the action. Or are you saying that it can't? If 62,000 psi is too much, what pressure is acceptable?

Or, is the established international pressure level criteria not applicable to combination guns somehow?

And, since barrel sets are interchangeable in the Valmet 412, then all the actions must also be identical.

The .308 also happens to have a somewhat higher pressure level than a .30-06, and a much higher pressure level than a 9.3 x 74R (or any other rimmed cartridge that I’m aware of: even the 30R Blaser, which is nipping at the heels of a .300 Win Mag in energy levels, is only 59,000 psi). So a .308 is (perhaps) the 'worst case' chambering in a combination gun.

So, if even a Valmet 412’s action can withstand a .308 in the upper barrel, then the Valmet 412 must also be able to withstand the stress of a .308 OVER a 12 ga shotgun. Or don't I understand something fundamental here?

Given that the Valmet 412 also has a 12ga O/U barrel set, I just cant see how ‘reversing’ the combination barrel setup would be much of a problem at all. The space necessary in the lower part of the breech to accept the larger shotgun barrel is already there, and the strength necessary in the upper part of the breech to withstand the .308 pressure level is also already there. So, what am I missing?

Or, is the top barrel of the Valmet .308 O/U double gun not really usable? Perhaps the bottom barrel is fired first and it was hoped that the top barrel wouldn’t ever be used that much?

But if the Valmet 412 is as good as everyone on this forum seems to believe, I can’t believe that Valmet designed it around an action that wasn’t capable of withstanding ANY stresses likely to be imposed on it.

No: the lack of rifle over shotgun combination's has little to do with cost or action strength, and much to do with visions of the ‘great white hunter’.

Best regards,

Steve

[dougk]

Steve
you bring up an interesting point.  I was originally in the rifle over shotgun camp until I started using double trigger on all my SxS shotguns and combo guns.  I find having the second trigger to control the rifle (bottom barrel) provides a more controlled trigger pull vs the front trigger which controls the shotgun barrel (top) in combo guns.  Also with my double rifles (O/U) I regulate the top barrel for closer shots while the bottom barrel is for longer distance shots, due to the better trigger pull on the second trigger.

So from my perspective it is all about the trigger pull given I use double triggers.

[Drilling Man]

  I'm NOT going to answer your book, line by line, but i will answer a few things pertaining to the 412.

1. All 412 bbls need to be fit to the action "they will be used on", so they are NOT exactly the same.  NOT doing this, will show you what a 308 will do to a 412 action.

2. If you take any DR set, you will ALLWAYS get to max pressure in the "top bbl., BEFORE you do in the "lower" bbl..  That alone is proof enough that O/U actions handle the pressures better in the lower bbls...

3. 412 bbls tend to have chambers and throats on the large side to relieve some of the pressure, on the high pressure cartridges.

4. you need to buy one and study up a bit, before you figure you know it all.   

  DM

[90north]

My "Staggs Built" has a 20 gauge over a 30-30, and I've come to appreciate the double triggers and it's quick mounting.  The shotgun is on top with the rifle below.

[dpastordan]

In Germany, I noted that it was more common to see the shotgun barrel on top.  Why?  I suspect it may be more to do with the use of the gun.  Most of the time the typical German hunter uses the gun as a shotgun, so having the top barrel the 12 gauge makes more sense as it swings and points like a shotgun.  Since many of the hunts are combinations...usually they will be shooting driven pheasant but will be allowed to take foxes and roedeer.  Having the lower barrel in .222 or .223 with a pop up rear sight then allows a rifle shot when one of those critters appears.  Then when one goes on a deer stand - a scope is put on (usually they have detachable claw mounts) to shoot the roe deer ...

[mcwoodduck]

Just a point of order:
A drilling is a three barreld gun.  Usually side by side shotgun with a rifle under - Favored by European Boar hunters.
But SXS Rifle is also seen and there are names for the two under the Drilling section- Sorry german names and I forget them.  But something like a dopple Bock or dopple flint?  Not sure.
Some are a shotgun under or over a rifle with a rimfire running along the barrel rib.  Almost all three in a verticle row.

A Vierling is a 4 barreled gun-  Usually a drilling with a rim fire in the rib or a small center fire like a 22 hornet in the center of all three barrels of the Drilling.  there are All 4 shotgun barreled veirlings.  Not sure if it is two side by sides stacked or two o/u side by side. 

An over and under or side by side rifle - shotgun mix is called a cape gun, favored by the British as a meat gun in South Africa in the days of front loading black powder and colonial exploration.

[Drilling Man]

  Here's the German names,



  DM