doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Would You Buy an Out of Proof British Shotgun?

Wirnsberger shows 12/LC defined as chamber length " over " 3 inches. Is he wrong ?

I have a Midland Gun Co. gun with 3 1/4 inch chambers and the barrels are so marked: " For 3 1/4" Paper Cases". Maybe LC refers to these!

All the best

Skeeterbd

Seems to be some dispute on the LC. Baron Engelhardt, who's usually regarded as pretty authoritative on British proofmarks up to at least the 1925 changes, says over 3". Lee Kennett, who basically updated Engelhardt's work to incorporate the changes made in the 1950's, says 3" or longer.

There are some low pressure loads listed on imrpowder.com in the target section. I remember one that was RXP hulls, AA wads, 1150 fps, 1 0z at about 4200 psi. That would likely make the case length thing superfluous. Some of these powders can produce puff loads if the ammo has been in very cold conditions for some time.
Accurately comparing old proofs and pressures is a tricky subject with different standards, different measuring equipment, perhaps even different places measured complicating the situation. Wear and tear on the barrels may not be as important as wear and tear on the stock. Higher pressure means greater force per firing on the stock. On an old gun there may be shrinkage on the wood/metal interface, softer wood due to improper oils or water damage, loose screws, etc. Cracks can more easily occur on a great old stock.
Pressures will also vary due to thick paper vs thin plastic hulls.

After reading this thread over several times and even searching back to a lengthy discussion here back, I think 2007, I am understanding the issue. My last question is that with US loads at around the same velocities , I.e. 1145 + or minus, and the 9800 pressure mentioned, one thing I am not clear on and may have missed it herein is with factory US loads at, 1 1/8....... 1......... And 3/4......is it correct that all three, give or take will produce the same pressures? I know with the 3/4 factory load I feel less felt recoil and am perhaps assuming wrong that it is better for the old gun than the 1 1/8... So with whatever load weight, I am still over the 9800 pressure limit of the proof of the 1 1/4 limit even with the 2 3/4 chambers....so maybe I do not understand. As already mentioned the US factory loads give velocity, or drams....but no pressure disclosure.

Ps..it is just that trying to put it all together , especially with that 2007 thread, is like Stephen Hawkings String theory, Quantum Mechanics and black holes...so I am just trying understand the pressure in the three common loads and if it makes any difference as to the intergrety of the gun, both as to danger and or beating the gun up....I did get various opinions here...one do not use, use but do not worry about pressure be more concerned with beating the gun up....hope you can still have patience with this dummy.

Condor, don't feel bad. It's a very complicated subject. Pressure does not relate directly to either velocity or shot charge. But velocity and shot charge are the most important components of recoil, and reducing recoil is a very good thing for old guns to avoid cracking old and maybe oil-soaked stocks.

It's my understanding that the major American ammo makers don't put pressure on shotshell boxes because they sometimes change from one powder to another. They strive for 2 things: Constant velocity, and pressure within the 11,500 psi SAAMI limit (for 12's). They don't really care about pressure because they assume you're shooting a gun that meets SAAMI standards. European shotshells, on the other hand, have to conform to CIP standards--which means that if they're for standard proof guns, the pressure ceiling is about 800 psi lower vs SAAMI. In this country, RST and Polywad offer low pressure loads, and Kent (Gamebore) and B&P shells that meet European standards are also available.

With older guns, you want to hold down both pressure and recoil. One reason American factory loads--especially some of the very fast hunting loads--are bad for vintage guns is, even if there's not a pressure issue, the velocity results in a lot of recoil. You don't need 14-1500 fps in a lead shot load to kill pheasants anyhow. 1200 fps or so has worked quite well for a very long time, and the last few I've cleaned haven't been wearing Kevlar.

L. brown, thanks very much , so as being my teacher so to speak , if I say this, with the Grant mentioned above, with the 2 3/4 chambers and 1 1/4 max loads proofed in England , even though stating for "American " casings, would be for loads current at the time in 1907. Since those have changed with SAAMI....any of the three US Target loads mentioned in my post above, or for the sake of argument, similar Game loads, all with generally the same velocities at sub 1200 fPS, would STILL be over the pressure limits conceived with the Grant Boss barrels were made(CIP). But, those lower velocities might still be ok to use as stated since one does not need higher anyway...which I agree for field hunting...but since velocity or shot charge does not necessarily relate to pressure....I should still use a shell like RST......for pressure and recoil.....and could use the lower US Factory load of a 1 once or 3/4 load only for the benefits of low recoil, but still must face up to the higher pressure issue not intended when the gun or barrels were made....would you give me a passing grade on what I just wrote?

One of the nice things about most reloading info is that it DOES give pressure info although it is current pressure measured with current equipment. Some manufacturers do sell low pressure rounds but remember that most trap/skeet loads while low velocity and light shot charges use cheap powder which is rather high pressure. Reloading still gives you the most control over pressure.

Just at a quick glance in an old Alliant handloaders guide I find a 12ga 2 3/4" load giving 1� oz of shot 1330 fps velocity @ a pressure of 9,500 PSI.
From the same hull but different powder, wad & primer 1 oz of shot is given 1200 Fps @ a pressure of 10,600 PSI. Thus 80% of the shot weight is given 90% of the velocity at an 11.5% increase in pressure. The heavier load in spite of its lower pressure will give you more recoil & put more force into the stock.
It is somewhat debatable as to just which parts of the gun the lighter load with higher pressure will actually be harder on.

Unfortunately, I do not reload...but I have had it all wrong...you can tell I felt the lighter load, the 1 ounce or 3/4 ounce , with the light recoil would have ALSO been less pressure...I had it all backward......the debatable issue of what's best is RST...as has been stated.....it is a non sequitur to me that . If I used 1 1 /8 load , the pressure would be less than the 7/8 ( I was stating 3/4 before...Iwas wrong, I meant 7/8ths)' but the recoil greater!.....with ample wall thickness I can use any shot...but would be better with the Lighter load for less recoil although debatable depending on the powder. I use RST on my 2 1/2 guns...but with the Grant as an example I am using:

1.BP..Competition One...2 3/4, G. 24 , 7/8 once ( do not know pressure)

2. Federal Ultra, 2 3/4, 1 oz., 1180 fPS ( do not know pressure)

...thinking these would be fine...why, less recoil on the old Gun...AND wrongly thinking less pressure....but as stated by one poster I should not worry that much about pressure and be more concerned with the recoil on that Gun.

3. federal Target load, 2 3/4 dram, 1 1/8 oz shot..1145 fPS....I would NOT use this on the Grant

Basically , This all the info on the boxes.

Any of these could be 8, 9, or 7 1/2 target shot size
For birds, I would simply use RST and as stated should not even worry about all this but use the RST...I guess I may have to start reloading

Sorry, I am being repetitive.....but it took all this just to find out I had it " generally" backward.... I just could not work it though all the posts and mathematics.