Shotshell Pressure Question?

[Harry Collins]

Bruce just mentioned the WW Xtra Lite 1oz. I have shot this load through an 1881 lifter with Twist barrels at the Southern. I reload this hull with WW 209 primers, Claybusters equivilent of WAA12SL wad, and 19.5 grains of WST (Winchester Super Target), 1 oz of shot for 7400 psi at 1180 fps. I shoot it through all my Damascus and Twist Parkers. The pressure is about 2000 psi higher than a 1 oz load with IMR 7625 powder, but WST is cheeper to reload.

Harry

[Bill Bates]

Okay I guess I'll don some proctective gear like, gloves, oil cloth faced pants and an old hat and see if I can knock some leaves off the aspens this weekend with the GH.

[Mike Stahle]

Originally Posted by Bill Bates

Okay I guess I'll don some proctective gear like, gloves, oil cloth faced pants and an old hat and see if I can knock some leaves off the aspens this weekend with the GH.

Bill, did you ever have the barrels refinished on your GH?

[Roundsworth]

Bill, I was a bit apprehensive when test firing my Damascus LeFevers! I even took some external measurements to see if the barrels expanded. No worries! Even the reamed/honed 'G' Grade held up! Buck Hamlin chuckled when he told me that my LeFever barrels would 'take anything I stuck in 'em'. I don't recall if this statement was made before, or after, he endorsed my choices of cartridges, RST and Polywad. I plan on using my RBL most of the time when chasing the grouse. I have 2 lifters and a LeFever to rotate amongst when I get bored with the RBL. I don't anticipate firing thousands of rounds through my antique shotguns, so I think they will last a few more generations. Even though the barrels, Damascus, Twist, and Laminated, are stout, I like to lean toward the mild side with my ammo. If I ever decide to hunt bigger birds than Ruffed Grouse, I know that my guns will handle some stiffer loads (from the vast menu at RST!) Cheers!

[Bill Bates]

Originally Posted by Mike Stahle

Bill, did you ever have the barrels refinished on your GH?

The barrels I was thinking about refinishing were on a LC Smith but the gun just had to many other minor issues that in total added up to more work than it was going to be worth.

The GH, after lots of time with 0000 steel wool and oil to remove the fine layer of rust that covered it, cleaned up great. The GH was one a youngman inhereited from his grandfather along with several other nice guns. The youngman left in the plastic slip case and stored them for five or six years in his garage. All the guns looked like they were in high conditon when they went into the case and got stuck in the corner. When I saw them they all were covered in anice fine red/brown layer. It just about brought tears to my eyes. The bores on the GH when I opened looked like they had been honed yesterday. The wood look good and the gun was tight as a tic.

Here is a pic of the barrels after some work to remove the rust and some Formbys Tung Oil to coat them.



I think they look great with the age on the rest of the GH.

So this weekend I'll give it try. Hopefully I won't be typing with my elbows next week.

[Mike Stahle]

WOW they look great Bill, ya done real good.
Maybe after you proof test her, and you still have a
shutter finger left, you can get pretty Ms. Wanda to model
that little GH

[Paul Harm]

Mike, recoil is the weight of the powder,wad, and shot X the FPS- not pressure. Pressure has nothing to do with it. Just because you felt less recoil with the modern shell doesn't mean there wasn't a lot of pressure. BP loads always have more recoil because there's a lot more powder weight in the shell, hence more recoil. Paul

[Mike Stahle]

Interesting read by Randy Wakeman

SAAMI Shotgun Pressure Specifications


Shotshell Maximum Average Pressure (MAP) in PSI


10 gauge 11,000
12 gauge 11,500 (except 3-1/2 in.)
12 gauge 3 1/2 in.14,000
16 gauge 11,500
20 Gauge 12,000
28 gauge 12,500
.410 Bore 2 1/2 in. 12,500
.410 Bore 3 in. 13,500

Pressure is discussed a great deal in a casual sense, but like most things unseen and unmeasured by most . . . little valuable information is normally imparted.

Lab data does not measure or indicate pressure in your gun. In the case of many factory shotshells, specific pressure is not discussed. In some cases, it cannot be reliably mentioned, as shotshells are marketed on the basis of performance, not SAAMI pressures. Shotshell manufacturing is a very competitive business; some shotshell makers (like rifle cartridge makers) have multiple approved recipies for the same shell-- the "why" is so they can buy and use whatever powder, many of them bulk or proprietary powders, that is found to be the most economical at the time. It could be St. Marks Powder one day, Nexplo the next, and ADI for the next run.

With shotshell chambers varying in length and diameter, exact pressure cannot be predicted. A simple primer change can change pressures by 3000 PSI. My friends at Accurate Powders / Western Powders inform me they have seen 5000 PSI changes just by a primer swap through their test barrels as recorded by radial tranducer.

Peak Pressure has no relationship to shotgun recoil, and so is not part of any free recoil formula. As published by Lyman and other sources: E = 1/2 (Wr / 32) (Wb x MV + 4700 x Wp / 7000 x Wr)squared.

Where E = recoil Energy in ft. lbs., Wr = Weight of rifle in pounds, Wb = Weight of bullet in grains, MV = Muzzle Velocity of bullet in feet-per-second, Wp = Weight of powder in grains.


Pressure, peak or otherwise, does not exist as part of free recoil. It likely won't stop those who think a tiny peak pressure node level equates to recoil, or enjoy speculating that that there is a relationship-- but there is no basis for it, unless we have a brand new branch of physics that attempts to now address it..

Peak Pressure, that always happens inside the shotshell, also has no relationship to pattern quality. Peak Pressure must always follow the base of the wad. When "pressure" is discussed, it invariably means only the peak pressure node that exists for mere fractions of a thousandth of one second. As its existence is so very fleeting, it cannot and does not illustrate the entire pressure curve-- nor even a substantial portion of it. Oberfell, E. D. Lowry, Zutz, Brister, Brindle ... no one familiar with exterior shotshell ballistics has postulated, much less shown, that peak pressure does anything to patterns one way or the other. If you follow the logical continuation of the discussion, a reduction of 3000 PSI must equate to something in pattern percentage. It doesn't, not one percent, and so the entire discussion moots itself in one big hurry. There is also nothing to show that higher peak pressure means more "open" patterns: if it did, every skeet load made would be at the highest MAP pressure possible-- quite obviously. Naturally, they are not. The peak pressure always happens inside the shell, before shot touches the first forcing cone, or the second forcing cone we like to call the "choke."

The bump up in pressure in the "newest" popular chambering, the SAAMI 3-1/2 inch 12 gauge, allows the 3-1/2 in. 12 gauge to effectively obsolete the 10 gauge when used with steel or other no-tox shot not subject to deformation. It allows a payload (or velocity) increase for the gauge beyond what can be had with the old 12 ga. 11,500 PSI MAP limit.

We all like to think of "pass / go" and "good / bad." We also have difficulty accepting that a "pressure number" is a vague one, contingent on our gun, our ambient conditions, and tolerance stack-up. Wad material variances affect pressure, crimp depth affects pressure, hull basewad variances affect pressure, lot-to-lot powder variances affect pressure, lot-to-lot primer variances affect pressure as well. It is a very vague if interesting number, unknown by most shooters in their guns with any precision, and has no effect on recoil, patterns, and assorted other attributes attempted to be associated to the tiny, fleeting little peak pressure node.

[Mike Stahle]

IT JUST NEVER ENDS

http://www.shotgunworld.com/bbs/view...p?f=3&t=209636


http://www.shotgunworld.com/bbs/view...p?f=2&t=184155

[Bill Bates]

Wow, early this morning I risked life and limb. I shot the GH and survived. It seemed to handle the 2 3/4" Winchester Targets 2 3/4 dram, 1 1/8 oz. 1145 fps loads with out a hitch.