Please define LOW PRESSURE LOADS

[John Aug]

Hi Guys, I'm new to this site. I have been looking through the archives for this answer to no avail.
What is concidered Low Pressure. I shot double guns most of my life until steel shot became my reality.
Well I'm back!! I bought some Nice shot for my Sterlingworth and want to load some low pressure rounds
for the early duck season. I've done a lot of research and have some 1oz loads in mind but would appreciate
any input you can give me. Is there a definate upper limit to low pressure? I feel like I'm loading GOLD!!
Great Site, thanks alot, John

[Fin2Feather]

John,

I'm not sure if Russ Gray posts here, but you can contact him on the 16ga.com site where he posts under the name RWG. Russ is part of a low-pressure loading group; I'm not a member but those who are say you'll learn everything you ever wanted to know and more there.

Fin

[Twice Barrel]

John Sterlingworth's and Fox guns in general are well designed and strongly built guns. If your gun is in good original condition and remains tight on face and as long as you shoot shells of the appropriate length maintaining pressures below SAAMI standards you will have no problem as far as pressure goes. The main problem with vintage guns are the stocks which over time can become oil soaked or have unseen cracks develop in the head of the stock. Excessive recoil caused by shooting heavy loads at high velocities have done more damage to vintage Fox guns than so called high pressure loads. In my small frame Foxes I limit the recoil to 13 ft lbs for high volume target shooting and 20 ft lbs for my heaviest hunting loads. This may sound pretty conservative to some but I had the head of the stock of my favorite 16 gauge start cracking even at those conservative numbers. A solid repair and glass bedding the stock to the action has got the gun back in action and we took some mountain Sharp Tails in Colorado this past week.

For the purposes of the 16 Gauge Loaders Group chamber pressures at or less than 9500 psi are widely considered low pressure.

[John Aug]

Twice, I appriciate the input. If I am loading 1oz 12ga shells so won't lower pressure
equate to less recoil? How do you measure felt recoil? Do you think glass bedding
would be a good preventative measure?
Thanks again, John

[Twice Barrel]

John there have been several long dissertations on recoil versus chamber pressure recently on other boards but to touch lightly on the concept of recoil. Recoil is determined by shot charge weight, velocity of the shot charge and weight of the gun. I'll just say that chamber pressure has no bearing on recoil except as it effects velocity but you can have two loads one generating a lower velocity at a higher chamber pressure because of the powders burn characteristics.

Here is a formula you can use to calculate recoil
for various loads:

http://www.10xshooters.com/calculators/ ... ulator.htm

As far as glass bedding the stock head that is a personal choice. If the wood looks solid and you keep the loads mild and the action tightly secured to the stock it probably isn't necessary but after my experience I have decided to glass bed all of my "shooting" vintage doubles.

[Silvers]

Twice Barrel has good advice on keeping pressures below SAAMI max. How far below? Well, a reference I have circa 1908 states service pressure max is 3-1/2 tons with hot shells that might have been left in the sun. Of course that was with bulk and dense smokeless powders then coming in use. I'm pretty sure the writer was referring to the standard US ton of 2,000 pounds, not the long ton.

So, how do advocates of shooting modern SAAMI max pressure shells (~11,500 psi) in 70 - 100+ year old Foxes reconcile that use in view of the Warning labels printed on every box "use only in modern guns in good condition originally designed for this gauge and length"?

Silvers

[Twice Barrel]

So, how do advocates of shooting modern SAAMI max pressure shells (~11,500 psi) in 70 - 100+ year old Foxes reconcile that use in view of the Warning labels printed on every box "use only in modern guns in good condition originally designed for this gauge and length"?

Silvers

First let me say that I am in no way an advocate of stuffing an old Fox or any other gun with a max load Roman Candle load but considering some of the work that Sherman Bell has done with Damascus barrels I think that we are selling our vintage guns short on the amount of chamber pressure that they can safely withstand. It is pretty simple for me to reconcile use of SAMMI compliant loads in any of the Fox guns that are tight and on face. As I am sure that you know SAMMI standards have been around since 1926 which is not a long time after Fox first started building their guns and to my knowledge Fox guns manufactured before and after 1926 have been quite capable of handling all SAMMI compliant loads without any design or manufacturing changes except for the lengthening of the standard chamber from 2 9/16th inches to 2 3/4 inches in the late 1930s from pre SAMMI produced guns.

Perhaps Dave Noreen can chime in on the chamber pressure used by Fox to establish their "Fox Proof" standard.

[fxe]

Twice Barrel,

Most of these vintage doubles were designed for 1 1/4oz loads or less with the exception of the Super Fox and the L.C. Smith Long Range or "Waterfowl". They were designed for 1 3/8 oz. I had a Sterlingworth with #1 weight barrels that I opened to 3" and shot 1 3/8oz. loads for 4 years through it with no ill effect.

Get an IMI Powders loading chart. They have the best loads for low pressure that I have found. I load NICE Shot for the last 4 years with Winchester AA shells, Rem 209P primers, 27.5 grains of High Score 800x, Rem SP12 wads and 1 1/4oz. Nice Shot to get a velocity of 1280fps and 7800psi! That is a nice load. If you want to use Federal Gold Medal plastic hulls and 33 grains of SR4756 you can get that 1 1/4oz of shot to travel at 1315fpx and only hit 7400psi. As far as chamber pressures go, that is indeed a very low pressure shell. There are 1 1/8oz loads that go out the barrel at 1200fps and stay under 5500psi. I shoot those in damascus with mild pitting if you have the nerve!

Anybody that loads should check out that handloader's guide from IMR. Low pressure with modern payloads and velocity is easily obtained.

Hope that helps,

Jay Shachter, Vintage Firearms, Inc.

[Twice Barrel]

Jay I understand that relatively high velocities can be achieved at low pressures with very slow burning powders such as some of the IMR and SR powders, HS7, SOLO 1250 and Blue Dot. My only problem I have with using these powders is their rapid drop off in performance , sometimes to the point of unreliability, in cold weather.

[fxe]

Twice Barrel,

The 800X powder is my main load for my duck hunting. We have a 3 day late season on the holiday weekend of January 1rst. Most often the weather is so cold we can only hunt rivers and the ice is broken on the way out, and on the way back in. I would say last year was my coldest day with 18 degrees all day long (and a 20 mile an hour wind. Duck hunting is an adventure!). 9 ducks, 9 Greater Canadian geese, never a blooper to be had.

J

[John Aug]

OOPS!

[John Aug]

Thanks again for the input,
I have used red dot powder in AA hulls since I started loading and had great success
for all my uses. I hunt ducks almost exclusivly but do not shoot long. When lead was legal
My favorite load for layout hunting was 1 1/8oz of #7 1/2 shot the same as the trap loads I shot then.
Last year my favorite early load was 1oz of #6 steel. I was looking to load Nice shot 5's & 6's in
AA casings 1oz shot, 16.5 gr powder, 7900psi at a velocity of 1150. It is lighter than my old trap loads
but I know the powder is reliable. Is there anything wrong with my thinking?
fxe, thanks for the lead on the IMR powders. There are a lot of interesting loads over there and I
may have to break out of my powder rut!! I worked the same place for 32 years,married to same woman
for 37 years, Do you' see a trend!
THANKS AGAIN John

[Twice Barrel]

Twice Barrel,

The 800X powder is my main load for my duck hunting. We have a 3 day late season on the holiday weekend of January 1rst. Most often the weather is so cold we can only hunt rivers and the ice is broken on the way out, and on the way back in. I would say last year was my coldest day with 18 degrees all day long (and a 20 mile an hour wind. Duck hunting is an adventure!). 9 ducks, 9 Greater Canadian geese, never a blooper to be had.

J

Great fxe I'm glad you have a good workable load. Have you had the ballistics performance checked at those temperatures? If not Tom Armbrust will run some tests on chilled loads if you would like to know how they are performing.