Shot shells pressure.. how important..

[Big Friend Ten (BFT)]

Bruce,

That was an excellent point! Parker offered its guns in different frame sizes/weights for what I think would often be for heavier or light loads. I have a #5 frame 10 gauge lifter weighting over 12 pounds which would have certainly tamed a heavy black powder load more that a similar gun built on a #3 frame weighing "only" 9 pounds!

Mark

[J.B. Books]

Originally Posted by Bruce Day

Velocity is provided on the following table so while drams equivalent is stated only for DuPont smokeless, it can be roughly determined for other powders. Note the statement about where velocity is measured.

Anyone know how velocity was measured "over a 100 foot range" back then, radar guns, electronic chronographs did not exist?

[Bruce Day]

Its called a ballistic pendulum and versions have been in use since the 1700's. There are numerous treatises about how it works that are interesting to read for those who are interested in physics. Not wanting to sound like a know it all, interested people might check the internet for explanations and details. Its basically a target calibrated for weight of the projectile that moves when it is hit and the movement relates to momentum which relates to velocity. I remember reading a naval story mentioning the huge size of the ballistic pendulum that had to be used when measuring the speed of a 20lb cannonball.

Bruce.....and that's pitifully all I know about it......and I'm no expert.

[J.B. Books]

A pendulum hit by a 20lb cannon ball, that must have been quite the gong show! Engineers of generations past were very clever with "simple" tools.

[Harry Collins]

Winchester reloading data that equates to their AA EXTRA LITE is about 7,400 psi. THis load is AA hull, WW 209 primer, 19.5 grains of WST powder, WSL wad and 1 oz of shot as I remember. I shoot these reloads in an 1881 Lifter Parker with Twist barrels at sporting clays all the time. Shot a 96 with this load and that old gun a month or so ago.

[Paul Harm]

That's a lot better than I shoot. Way to go.

[Harold Pickens]

So, what kind of pressures do you want to stay under for Damascus, specifically 16 ga. I'm loading a couple of nice loads that are around 6000 psi that are fine. One uses International and Win CF and cheddite hulls and the other RGL's and 20/28 (thanks, Daryl). Is 9000 psi ok?

[Big Friend Ten (BFT)]

Harold,

Safe peak pressure in Damascus should be based on barrel wall thickness from the chamber to about 15". After that the pressure is so low that an old steel can would contain it. A barrel that thin would however dent or bend far too easily!

I have heavy Damascus barrels that will handle modern shells to the SAAMI mean working pressure. I also have a 16 gauge Lefever and a few #1 Frame Parkers with seeming untouched barrels that I would NOT shoot modern ammo. Oh, I think that would be fine but why take the chance? Certainly the recoil from modern loads (not necessarily high pressure loads) would not do any good for the stocks!

Loads at 6000 PSI are safe for almost gun with Damascus or twist barrels in the condition or close to as what they were when they left the factory. I don't worry much about 8000 psi but then I don't shoot guns with barrels with pits the depth of the Grand Canyon! If fact I did buy a DHE Damascus that measured about .016" where my forward hand would be. Although with 6000 peak psi loads they would have been safe I retired those barrels from service and rebarreled the gun. Why, because I might screw up someday and shoot a high pressure load in it. Or, maybe the net caretaker would. I am a big fan of fingers!

So, all the above stated, 6000 psi should be safe but have your barrels measured if you have doubts. My Hosford Barrel Wall Thickness Gage may have save my fingers in reference to the above described barrels. That may have been the best $600 I ever spent!

I'd have Damascus or twist barrels measured before I subjected them to 9000 psi peak. Even a heavy barreled gun may have been honed too thin. It is hard to maintain the concentric relationship of bore to outer diameter when honing without special tools. Even original Parker bores may not be as concentric as what appears to the eye!

Shoot well and shoot safe!
Mark

[Paul Harm]

Wayne, a friend gave me a seed bag of paper hulls - maybe 2000. I to would try and stay away from 9000psi - too many loads [ for reloaders ] that are around or under 7000psi.

[Double Lab]

Harold;
I'm glad the 20/28 worked out for you. Personally I try to stay around 7000psi. and as Paul says there are a ton of loads in that range. That's my comfort range and so far so good. By the way, I use these light loads primarily for my comfort, then comes the wear and tear on the gun and lastly for economics. I just can stand recoil anymore. Just maybe with age comes wisdom.