Kent Tungsten Matrix 12 gauge 1400 FPS safe in a 3 frame parker?

[Bill Holcombe]

I had a friend give me a box of 12 ga 2 3/4 KTM. I imagine I could shoot this in my early 60s superposed without worry, but is this a good load for a 3 frame parker 12 gauge or should it be the lighter load they make?

Just curious of the more experienced members on here.

Thanks.

[Drew Hause]

http://www.omahamarian.org/trap/shotshellenergy.html

Recoil in an 8# gun with 1 3/8 oz. shot at 1,375 fps is 36.3 ft/lbs.
For comparison, 1 1/8 oz. at 1200 fps, (3 Dram) 7.5 # gun is 23.0 ft/lbs

You might ask the head of the stock :(

http://pic20.picturetrail.com:80/VOL1373/6511424/15127852/270528918.jpg

[Rick Losey]

Staple time

This is why I recommend light loads for most older guns- Even if the barrels can take it, you need to think about 100 plus year old wood

I do fire the lighter Kent matrix in my 3 frame 12 VH. It had a small split started in the head. I have de oiled and reinforced it and am not worried. But I will still avoid the stiffer loads

[Drew Hause]

Or a prophylactic lag bolt ;)

http://pic20.picturetrail.com:80/VOL1373/6511424/15127852/410617110.jpg

[Bill Holcombe]

Thanks. I will save it for my superposed. Was just curious.

[Craig Budgeon]

The lag bolt repair looks like a repair that puts food on gunsmiths tables.

[Craig Larter]

OK so you guys think I'm nuts but I have a Super Fox in nice shape I shoot regularly with 1 3/8th Oz TM. That's what it was designed for and no issues so far. My 2 and 3 frame 12ga Parkers I shoot 1 1/8 Oz bismuth handloads.

[David Fishley]

You would think they could have timed that lag bolt.

[Pete Lester]

Even these guns were new I don't think they saw loads like 1 3/8 ounce at 1375 fps. Speed hurts patterns and makes excess recoil. If you shoot classic double guns reloading opens up far more gun friendly loads. Think "Period Correct", 1100 to 1150 fps will kill anything in shotgun range with the right size shot. The old timers increased the mass of the pellet not the speed of the payload for the desired result.

1 3/8 ounce at 1100 fps in an 8 pound gun has 32% less recoil than a load going 1375 fps.

[Bill Holcombe]

My shells are only 1 1/4.

[Pete Lester]

My shells are only 1 1/4.

Those Kent shells at 1 1/4 1400 fps will produce 34% more recoil than a 1 1/4 ounce load launched at 1100.

[Bill Holcombe]

1400 fps is what the box says. I was just clarifying as I had never stated the load.

[Pete Lester]

1400 fps is what the box says. I was just clarifying as I had never stated the load.

Sorry I did not see the MV in the thread title, 34% more recoil than a 1100 fps load all things being equal.

[Pete Lester]

I have enjoyed and found light loads very effective for many years. The old high brass 12ga lead load was 3 3/4 dram 1 1/4 ounce at 1330 fps. I don't care to shoot that anymore due to what I think is excessive recoil. The low brass 3 1/4 dram 1 1/4 ounce at 1220 fps was a better factory loading.

I reload and I try to keep my MV between 1100 to 1175 no matter the weight of the payload because it is pleasant to shoot and works great. I don't think loads with MV over 1200 fps offer any increase in effectiveness, only more wear and tear on gun and shoulder.

[Drew Hause]

Turn-of-the-century Live Bird and Inanimate Target shooters used some boomer loads.

January 2 1897
Charles Grimm defeats Doc Carver in Chicago for the “Cast Iron Metal”.
Grimm used a 12-bore L.C. Smith gun, 7 3/4 pounds, 3 3/4 drams “Schultze”, 1 1/4 ounce No. 7 shot, in U.M.C. Trap shell.
Carver used a 12-bore Cashmore gun, 8 pounds weight, 4 drams of Carver powder, 1 1/4 No. 7 shot, in U.M.C. Trap shell.

The standard Live Bird load c. 1900 was 1 1/4 oz. 3 1/2 Dr. Eq. (1275 fps) BULK Smokeless with pressures about 11,750 psi; 1 1/4 oz. 3 1/2 Dr. Eq. DENSE Smokeless was about 12,600 psi.
The modern SAAMI 12g maximum 2 3/4" and 3" pressure is 11,500 psi

Competition guns were limited to 8# (not including recoil 'boot' or hand guard) and recoil with those loads would be about 27 ft/lbs.

[Frank Srebro]

OK so you guys think I'm nuts but I have a Super Fox in nice shape I shoot regularly with 1 3/8th Oz TM. That's what it was designed for and no issues so far. My 2 and 3 frame 12ga Parkers I shoot 1 1/8 Oz bismuth handloads.

Same as Craig, I regularly shoot the 1-3/8 ounce TM load in Super-Foxes and Winchester 21 Duck guns. Actually the later Supers were made after introduction of the 3-inch 1-5/8 ounce progressive load @ 1315 fps. I'll also shoot the Kent TM 3-inch 1-1/2 ounce load in factory chambered 3-inch Supers when conditions warrant use of the heaviest soft/non-tox shells. Same with the 21 Ducks and my Model 12 Heavy Duck pump gun.

[Carvel Whaley]

I agree with you Pete, in my NH 10ga I shoot 1 1/4 oz ITX at approx. 1100 fps. It seems to as good or better than my friends 3 1/2 , 1600 fps steel in ther auto loaders on geese. Carvel

[Bill Murphy]

What is the "point of duck" velocity of a 1200 fps load compared to a 1450 fps load?

[Tad Tadlock]

An African duck or a European duck?

[Pete Lester]

What is the "point of duck" velocity of a 1200 fps load compared to a 1450 fps load?

Bill I am either missing your point or not understanding the question.

[Kevin McCormack]

What is the "point of duck" velocity of a 1200 fps load compared to a 1450 fps load?

About a freight car length lead! I'll trade velocity for increased payload weight any day!

[Kevin McCormack]

Same as Craig, I regularly shoot the 1-3/8 ounce TM load in Super-Foxes and Winchester 21 Duck guns. Actually the later Supers were made after introduction of the 3-inch 1-5/8 ounce progressive load @ 1315 fps. I'll also shoot the Kent TM 3-inch 1-1/2 ounce load in factory chambered 3-inch Supers when conditions warrant use of the heaviest soft/non-tox shells. Same with the 21 Ducks and my Model 12 Heavy Duck pump gun.

Ditto Ditto Ditto! - With all the heavy clothing worn while waterfowling and the adrenaline rush when they cup their wings and drop their feet, who's thinking about felt recoil anyway! Last week at Beaver Dam we shot everything from 3" Mag 1 1/2 oz. to 2 1/2" (not a misprint!) 1 1/4 oz. Kent TM without so much as a hiccup! Big Birds; Big Guns!!

[Drew Hause]

1220 fps 3' from muzzle is 665 fps at 40 yds.
1400 fps 3' from muzzle is 691 fps at 40 yds.

[Craig Larter]

I hunt in a very large cattail marsh even with a master hunter dog you better put a late season mallard or black down or the chances of recovery are reduced. There is nothing like 1 3/8oz of TM #5's it just puts birds down in my experience. A trained retriever and big guns capable of digesting big shells will not disappoint. Just buy a Super Fox and a case of 1 3/8 Oz TM and learn to shoot if you want to experience waterfowling at it's best. The only better tool is a 10ga. 2 7/8" loaded with a heavy load of bismuth. OK beat me up.

[Pete Lester]

I have never lead targets, inanimate or live any differently when shooting 1100 to 1175 fps loads. When I miss it is not due to not leading the target by an additional 7 inches.

These are the leads for different velocity shells needed to CENTER a left or right crossing shot from station 4 on the skeet field, approx range 25 yards.

1145 fps 60.8 inches
1250 fps 56.8 inches
1350 fps 53.6 inches

[Kevin McCormack]

Before the advent of the cursed steel shot and the mandated non-tox, all we ever shot on ducks was the lead load of 3 1/4-1 1/4 #5s for decoyed ducks, and the 3 3/4-1 1/4-#4s for pass shooting on big puddlers or Canvasbacks and other 'heavy' ducks. After enduring the mish-mash of trying to match guns and ammo in the aftermath of the non-tox era, Kent TM or Bismuth rules for our vintage SxSs that need it, and Black Cloud is our choice for steel shot (#4s for ducks over decoys, #2s or 1s for pass shooting the biggest ducks, and BBs for geese out of a pit or BBB for pass shooting all geese. To each his own!

[Frank Srebro]

1220 fps 3' from muzzle is 665 fps at 40 yds.
1400 fps 3' from muzzle is 691 fps at 40 yds.

Drew, I presume those figures are for lead shot but you didn't cite the shot size(s).

Smaller shot will "bleed off" speed more rapidly than larger shot.

Also, bismuth shot is about 0.8X the density of lead and thus a bismuth pellet will lose speed at a faster rate than a lead pellet of the exact same diameter. Who has figures comparing the same pellet diameter of bismuth, ITX, TM and lead, at the same muzzle speed, along with their respective 40/50/60 yard speeds?

The bottom line for me is to use TM which is about as dense as lead, and to use the same payload and velocity as we did 30 years ago. I'll make an exception with lighter loads of bismuth for closer work and decoyed birds but I'll let longer range birds pass without shooting if that's what I have in the gun and there's not enough time to switch shells.

We usually only hear about the day's bag. When was the last time someone posted how many birds were feathered, crippled and lost with light loads that were overstretched?

[Tad Tadlock]

Who has figures comparing the same pellet diameter of bismuth, ITX, TM and lead, at the same muzzle speed, and their respective 40 yard speeds?

This link Kent Cartridge Return Of Bismuth (http://www.randywakeman.com/KentCartridgeReturnOfBismuth.htm) and the Ed Lowry article that is referenced have data for bismuth, steel, and lead.

[Drew Hause]

No. 8 shot and you are correct Frank.

And thanks Tad; the short version
Steel #2 MV 1400 - 40 yds. 865 fps
Lead #5 MV 1330 - 40 yds. 710 fps
Bismuth #4 MV 1350 - 40 yds. 696

[Drew Hause]

Western Cartridge Co. never marked the Super-X ‘Field’ or ‘Record’ boxes with “Dr. Eq.” stating only “Maximum Load”. It is presumed that 12g ‘Super-X Field’ 2 3/4” 1 1/4 oz. was 3 3/4 Drams Equiv. or 1330 fps, and the 3” 1 3/8 oz. ‘Record’ was 1275 - 1295 fps (the speed of 1 1/4 oz. 3 1/2 Dr. Eq. loads).

In a 1927 Western Cartridge Co. flyer “Super-X The Long Range Load” by Capt. Chas. Askins the 12g “Duck Load” (not specified but presumed to be 1 1/4 oz. Super-X “Field”) is described as 3 1/2 dram (38.5 gr. Powder; also not specified but no doubt DuPont Oval) #4 shot at 1400 fps (at the muzzle rather than 3 feet) and 1000 fps at 40 yards, with a breech pressure of 3 3/4 tons or about 11,480 psi by Burrard’s conversion.

From the 1928 edition of “Smokeless Shotgun Powders” by Wallace Coxe, ballistic engineer of the Burnside Laboratory of the E.I. du Pont de Nemours & Co.
3 1/2 Dram Eq. 1 1/4 oz. presumed #6 shot loads (1275 fps) and 40 yard fps:
NOTE: pressures were measured by crushers (LUP) and modern transducer measurement pressures would be 10 – 14% higher
DuPont Bulk smokeless powder - 11,700 psi, 943 fps
Schultze Bulk smokeless powder - 11,800 psi, 941 fps
28 grains of Ballistite Dense smokeless powder - 12,600 psi, 966 fps
All 3 are greater than the SAAMI 12g 2 3/4” recommended maximum pressure of 11,500 psi.
40 grains of DuPont Oval Progressive Burning powder - 9,400 psi, 981 fps

[Rick Losey]

it would be interesting to have some of those original revered loads tested to see how they actually perform in velocity and pressure

the loads (and some matching guns) were marketed to be game changers to the average shooter

i expect a great long range shooter like Nash Buckingham could make any satisfactory load look like a winner in Bo Whoop or any properly choked gun

[Frank Srebro]

Western Cartridge Co. never marked the Super-X ‘Field’ or ‘Record’ boxes with “Dr. Eq.” stating only “Maximum Load”. It is presumed that 12g ‘Super-X Field’ 2 3/4” 1 1/4 oz. was 3 3/4 Drams Equiv. or 1330 fps, and the 3” 1 3/8 oz. ‘Record’ was 1275 - 1295 fps (the speed of 1 1/4 oz. 3 1/2 Dr. Eq. loads).



Thanks Drew for that additional information. Regarding the 3-inch 1-3/8 ounce load, I have a reference that its speed was 1315 fps, probably at 3 feet as generally measured in the US.

So now I have a question. Several of your posts here have referenced "Burrard's conversion" of tons (pressure) to psi. I've seen many period references in American sporting literature to shotgun breech pressure and stated in tons. For example, that production Winchester 21's were proofed at 7-1/2 tons. Another example from almost 90 years ago, verbatim, "pressure limit generally considered to be 5.00 tons per sq inch". The underscore is mine.

So, why would it be that American readers needed to reference a little known conversion to convert tons to psi as measured with lead crushers?

[Drew Hause]

Long version Frank :(

Wallace H. Coxe, in “Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics” published by E.I. du Pont de Nemours & Co., 1927, “Measurement of Pressures”
The common method of taking pressures in small arms in this country is known as the Radial Pressure system. A housing is built around the barrel, and a hole drilled through the housing and barrel into the chamber at a distance of 1 inch from the breech and at right angles to the axis of the bore. The hole is then bushed and drilled to a uniform diameter of 0.2250 inch. Then a piston is made the length of the piston hole and 0.2250 inch in diameter. Next the piston hole is lapped to permit the piston to fit snugly without either sticking or getting out of alignment.
In firing the gauge, the piston is inserted and seated, then a lead crusher cylinder is placed on the head of the piston and held firmly in place by a screw and anvil attachment built into the housing. When the cartridge is fired, a portion of the same gas pressure that pushes the bullet through the barrel drives the piston against the lead cylinder and compresses it.
The length of the lead crusher cylinder after compression is naturally less than before the shot was fired and the difference between the original length and the length after compression therefore represents the amount of pressure which has acted upon the lead. Thee exact pressure is read from a table giving a pressure reading for every remaining length reading and commonly called a Tarage Table.
Pressures that are determined at ballistic laboratories are merely relative values and are not absolute values.

NOTE: The Tarage Table conversion may be for pressure expressed as Tons / Sq. Inch or Pounds/ Sq. Inch (PSI).

September 1931 American Rifleman. “Standard Shotgun Pressure Barrels”, by Merton A. Robinson, Ballistics Engineer, Winchester Repeating Arms Co. The article described in detail the crusher method of pressure testing, with images of pressure barrels then in use by Peters, Hercules, Western, Remington, Winchester, Du Pont and Federal. Although the barrels were of somewhat different designs, they were ALL crusher barrels, without evidence of piezoelectric transducers. (Courtesy of Larry Brown)

Major Sir Gerald Burrard published an estimated LUP (Long) Tons/ Sq. Inch (TSI) to piezoelectric transducer Pounds/ Sq. Inch (PSI) conversion formula in the Third edition of The Modern Shotgun, 1955, Vol. 2 derived from simultaneous crusher and transducer pressure readings in a test barrel. He observed the under-reporting of pressure by (crusher) LUP compared to piezo transducer gauges:
“The calibration of lead crushers by means of the piezoelectric gauge suggests that lead crusher pressures are somewhat on the low side; 2 Tons per square inch being about 2.5 with the piezoelectric gauge…”

Estimated Long Tons Per Square Inch Lead Crusher Pressure (Cp) conversion to PSI (pound force per square inch) (Cp x 1.5) - .5 = TSI, TSI X 2240 = PSI. Using this formula:
3 Tons/sq. inch by LUP (crushers) = 8,938 PSI (pounds/ sq. inch) by transducer
3 1/4 Tons = 9,682 psi
3 1/2 Tons = 10,427 psi
3 3/4 Tons = 11,480 psi (The SAAMI maximum for 2 3/4” 12g is 11,500 psi)
4 Tons = 11,917 psi

“Eley Shooter's Diary 2005” - “The later transducer system uplifts the (PSI by LUP) values by approx. 14%.”

From the CIP site: confirmation that 850 BAR = 12,328 PSI by crushers (LUP) is actually 960 BAR = 13,924 PSI by transducers (13% higher)
http://www.chircuprodimpex.ro/produse/alice-non-toxice-de-vanatoare/cip-regulations-on-steel-shot-ammunition.pdf
“These cartridges, if they are to be fired from standard proof shotguns (ie those proved to 960 bar [transducer] or, previously, 850 bar [crusher]), or magnum proof shotguns (ie those proved to 1370 bar [transducer] or, previously, 1200 bar [crusher]) must not exceed the maximum admissible service pressure of 74 MPa (new units “megapascals”, in place of the old 740 bar) specified by the CIP and measured by means of a piezo-electric transducer.”



SHORT VERSION
If the tarage table conversion is expressed as psi - add 10-14% for modern piezoelectric transducer measurement
If the tarage table conversion is expressed as (long) tons - use Burrard's formula

[Drew Hause]

Rick: Tom Armbrust tried to pressure test some vintage 20s-30s loads. He found the results were too inconsistent to be meaningful related to primer (mostly) and powder degradation. Interestingly, some loads showed an increase pressure related to hardening and stiffening of the fibre wads and paper cases.

[King Brown]

Kent TM 1 1/4 at 1500fps is too much generally for any American classic, in my opinion. I bought a Beretta 686 to handle it.

[Frank Srebro]

Thank you Drew for all that work to explain the conversion. I greatly appreciate your efforts.

Just some thoughts: 1) that factor of 1.5 in the tons to psi conversion formula seems a little nebulous; and 2) all the period American literature I've seen uses the word "tons" as compared with "long tons"; and 3) I wonder why Burrard apparently didn't use the typical English "tonnes" to indicate the long/metric ton.

Some final comments, on the Kent TM velocity. I've tried but haven't been able to confirm where that figure is indicated. Whether that's at 3 feet, or is "extrapolated to muzzle velocity" as has been done on at least some UK shotshells in the past. That 3 feet makes a huge difference in speed (when measured so close to the muzzle) and of course a higher number sounds better in the adverts. Nonetheless I believe any Kent shotshell sold in the US adheres to SAAMI pressure standards, same as competing shells by US manufacturers. Maybe Kent has some secret magic gunpowder that produces much higher speeds than the US shell makers can do, but still at accepted max pressure? :rotf::bigbye:

[Drew Hause]

Coxe specifically stated in one of his DuPont pamphlets that the 'Tons' were 'Long Tons'

I still think the Brits just enjoy messing with us Colonials ;)

[Kevin McCormack]

"Maximum, Maximum, Maximum".......uh, sorry; just got finished watching "Gladiator" for the 54th time before going online - Duh!

[Frank Srebro]

Hello again Drew, further on that "Burrard's Conversion" of tons to psi:

I am still unconvinced it applies to converting tons to psi pressure as reported in American sporting literature. Just this morning I was reviewing tech info on Winchester 21's and I read Jack O'Connor (1949) who stated again that 21's were proofed at 7-1/2 long tons which he also cited as 16,500 psi. That's a simple multiplication without the little known "conversion" ..... 7.5 (2200) = 16,500

As I'm sure you know, lead crushers became outmoded after electronic pressure measurement came into general use in the US after the War.

All told I ask if you are sure that Burrard's conversion applies to American pressure as stated in long tons, or if it solely relates to British proofing? Thanks in advance for your reply.

[Frank Srebro]

Deleted duplicate

[Drew Hause]

Frank: the more we all think about this the better...and I still think the Brits enjoy(ed) messing with us :(

What I assume: The Tarage table used to convert compression of lead crushers (distance) to pressure reported either PSI OR Long Tons.

What I know:
This pressure/distance curve appears on p. 20 of "Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics" by Wallace H Coxe, 1931

http://pic20.picturetrail.com:80/VOL1373/6511424/24488932/409804775.jpg

On p. 21 Coxe states "The vertical line represents the pressures developed by the various powders. This is measured in long tons (2240 pounds)."

Major Sir Gerald Burrard wrote in the Third edition of The Modern Shotgun, 1955, Vol. 2 that pressures derived from simultaneous crusher and piezoelectric transducer pressure readings in a test barrel demonstrated the under-reporting of pressure by (crusher) LUP compared to piezo transducer gauges:
“The calibration of lead crushers by means of the piezoelectric gauge suggests that lead crusher pressures are somewhat on the low side; 2 Tons per square inch being about 2.5 with the piezoelectric gauge…”
And for that reason he came up with his formula to convert pressure as measured by lead crushers expressed in Long Tons to PSI as measured by modern piezoelectric transducers.
That ALSO means PSI as measured by crushers is less than that as measured by transducers, and “Eley Shooter's Diary 2005” states “The later transducer system uplifts the (PSI by LUP) values by approx. 14%.” Other authors say 10% - 14%.

What we don't know:
When were pressures reported by U.S. gun and ammo makers measured by piezo transducers?

We DO know that the Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives standards ratified in 1969 expressed the pressure numbers as transducer BAR converted to PSI.

BUT the darn Brits didn't adopt the CIP standards until March 1, 1980.

[Frank Srebro]

Thanks again Drew, I agree that the more we study this topic, the better.

Your other assumption is, there was a standard "agreement" between the US makers and their British counterparts to use the same protocols for testing, to include a standard location for the crusher on the pressure gun, the same crusher diameter/length, and the same chemically pure lead or lead alloy whichever it was. Do we know if there was any such agreement? I've never read of anything like that in period literature and frankly I don't believe the Brits tried to coordinate their pressure testing apparatus and protocols with what the US makers were doing.

All told and thanks to your work, it seems that Burrard had a good handle on a conversion formula for pressures as measured by the British. Does Burrard specifically mention in his book that his formula applies to the US makers and their protocols when they measured tons or tons/sq inch with the old lead crusher technology?

Also who has any references to "Burrard's Conversion" in recognized US shotgun ballistic literature? I've seen many references where American makers reported pressure in "tons" and generally that's been accepted as: tons X 2200 (as I learned in grade school) or as tons X 2240 (as the accepted value is today). The difference between using the factors 2200 or 2240 is somewhat insignificant relative to this discussion.

I agree of course that old US lead crusher numbers should be multiplied by 1.10 to 1.15 to convert to transducer psi. Nowhere have I read or seen anything other than: tons X factor X 1.10 to 1.15 to convert to approximate psi.

I thank you again Drew for this effort and all the other study work you do. I hope to meet you some day. :)

[Drew Hause]

It's been fun Frank, but hard for this non-engineer with a bit of math dyslexia - really a miracle I made it through chemistry and physics, but it was the U. of Mo. ;)

This is interesting

“Experiments by Mr. R.W.S. Griffith of the Schultze Powder Co.” in Sporting Guns and Gunpowder
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA38&dq

LOADS……….................……………..……………1 1/8oz….1oz.....7/8oz.
………………………………....................……………….12g…..16g…. .20g
Curtis & Harvey No. 4 T.S. Black Powder...….82….…74….…66 grains
Schultze and “E.C.” Bulk Smokeless.……....….42….…37….…33
Walsrode Dense Smokeless...………………........28…….24….…22
12g = 3 Dram or 3 Dr. Eq.
16g - 74 gr. BP = 2.7 Drams; 37 gr. Bulk = 2.64 Dr. Eq.; 24 gr. Dense Walsrode = 2.57 Dr. Eq.
20g - 66 gr. BP = 2.4 Drams; 33 gr. Bulk = 2.36 Dr. Eq.; 22 gr. Dense = 2.38 Dr. Eq.

Chamber pressures were expressed as Tons/sq. inch. If simply multiplied by 2240 the pressures are unreasonably low. Using Burrard’s conversion yields what seem to be accurate numbers:

………….....……..12……….16……...20
C.&H. No. 4…6,373…..7,078.…..6,944
C.&H. No. 2…7,459…..8,310...…8,288
Schultze……...4,424…..6,272.…..7,246
“E.C.”……..…..3,685…..6,171.…..8,322
Walsrode.…….9,363………......….10,741
S.S. …..….……9,800….....………….10,539
S.S. (Smokeless Shot-gun)

BTW: usually pretty nice in Vegas this time of year but rainy and cold Friday and yesterday with LOTS of snow across northern AZ. Come out to the show some time :)
Josh said he'd like to continue to have a significant Parker presence at the show.

[Frank Srebro]

Some additional data on American shotshell pressure measurement: Charles Askins reporting in 1929 on tests at DuPont's Brandywine Laboratory of the 12-gauge/3-inch load with a max charge of its Oval progressive burning powder, as "taken from a DuPont ballistic sheet":

37 grains Oval, 1-3/8 ounces of No. 6-shot ------> 4.50 tons per square inch

Now then, 4.50 X 2200 X 1.15 = 11,385 psi as converted to approx. modern transducer reading

Or, if you prefer, 4.50 X 2240 X 1.15 = 11,592 psi as converted

Right on par with the current SAAMI max mean pressure for 12-gauge/3-inch at 11,500 psi.

In net, I continue to believe that "Burrard's Conversion" doesn't apply to pressures of American factory shotshells and thus the guns designed for them.

[charlie cleveland]

i really like talking about the 3 frame parker 12 ga and the loads every body shoots..i have only shot 2 3/4shells with the 1 1/4 lead loads but i would not be scared to shoot heavier loads in it....my old 12 ga weighs 9 1/2 lbs so not much recoil it is a good squirl gun...charlie