Shotshell Pressure Question?

[Austin W Hogan]

Jack, Mark, Drew; I think Jack's recent post frames my concerns rather precisely. Jack and Mark cite British proof of 3 1/4 and 3 1/2 Tons. If those are tons made of English pounds, and expressed as the force on English square inches, they are pressures of 6500 psi and 7000 psi. Metric tons and English square inches raise those numbers 10%. If they are metric tons and metric centimeters squared, they are about 15000 psi, comparable to SAAMI proof loads.
Measuring transient pressure, especially when the total event occurs in milliseconds, is not a precise experiment; the numbers quoted always have to be referenced to the time that the pressure is averaged and the measuring instrument.
That is the reason I prefer to choose a gentle load from a simple shot column length and shot speed. I know that a shot column 1 inch long leaving the gun at 1300 ft/sec is pretty hot irrespective of gauge; a shot column 3/4 inch long leaving at less than 1200 ft /sec is pretty mild.
I think RST tables back me up on this; 10 ga 1 1/8 ounce (.686 inch), 12 ga 7/8 ounce (.603 inch ) and 3/4 ounce (.520 inch), 16 ga 7/8 ounce (. 732 inch) and 3/4 ounce (.626 inch), 20 ga 3/4 ounce (.672 inch)and 28 gauge 5/8 ounce (.756 inch) all at less than 1200 ft/sec are without a doubt very gentle loads, and it is not necessary to quote pressure to verify this.
Incidentally, Parker, prior to the formation of the interindustry for runner of SAAMI in the 1920's, proofed by lengthening the shot column (adding more shot weight, not powder weight) according to TPS.

Best, Austin

[TARNATION !!!]

Originally Posted by calvin humburg

Jack, I used to take a lot of pictures years back slr under stood it film speed f stop yahda yahda, then they made them into computers I kept shooting the slr (I don't need 1 of thoes goofy cameras) well here I am I want to put pictures on here so I go to wally world to get me one or use my daugthers what are the guidelines to get a good picture the pixles or what ever. Thanks ch

Calvin: Bill pretty much says it all. I agree for computer purposes anything beyond the 3MP is more than needed and everthing out there is way beyond 3MP now anyway. If you mastered the SLR, all the concepts remain the same for a DSLR but you can do a bit more with the camera that might have been done later in the film processing, like enhanced color saturation. I agree fully with Bill, if you have good lenses with your film camera, try to see what you can find that will accept those lenses or see if there is an adapter that could make them fit. If you want control (f stop/shutter/iso/white balance/dof/manual focus etc), you won't want a point and shoot, although there is plenty you can do with them and they are convenient for their ease of carrying anywhere. Looking forward to seeing some pics.
Cheers,
Jack

[Bruce Day]

TPS, Fig 12.16 , p. 515. Jack's gun, assuming 2 5/8" chambers, would have been proofed by Parker using charges that generated an average of 6.1 long tons and 13, 700 pounds and a maximum of 6.7 long tons and 15,000 pounds. Actual and theoretical service limits for ammunition intended for use in the gun are also provided. So if Jack goes down to the local gun shop and buys a flat of Winchester AA Xtra Lights ( 8500psi ) for example, he is 1000 pounds under the average factory load pressures (9500) for which the gun was built.

As another example, say that I want some 16ga shells to go pheasant hunting. I can handload, buy RST's ( which are great shells) or I can get Federal 1 oz Game Shoc loads at my local hardware store. These are 1oz, 2 1/2 dram, 1165fps loads and develop 7, 400psi. From the Fig 12.16 table, I know that my 16ga with 2 9/16" chambers was intended to shoot ammunition that averaged 10,100psi, so they are 2,700psi under the service working limit average. But these Federals are marked 2 3/4" on the box, yet only 2 11/16" when I measure the expended shell. So these shells are 1/8" over the gun chamber length, and precisely as Parker intended for good sealing.

[Big Friend Ten (BFT)]

Austin,
I've been studying this subject but for a while. I don't know enough to teach but for what it's worth:
- During the period when the British proofed in Tons (Long Tons) it was by the Lead Crusher Method. That was by a Government approved proof house. One would imagine that if for the British Gov't it would err on the side of caution.
- SAAMI uses the piezo-electric method which can be measured and recorded in micro-seconds if one has the equipment.

So... Shooting a higher pressure load than 8000 PSI in Parker Damascus (or LC Smith) is a personal choice. My daily shooting is with 6000 PSI in 12 and 10 ga which break targets just fine. I know the barrels will however withstand modern loads but I still reserve those for when I can't load a low pressure to do the job.

A good friend and member of this board made the classic mistake of loading shells with PB instead of the black powder which he thought was in the MEC powder bottle. PB looks like black powder. His barrel blew on the 4th shot. He later had the remainder of those shells tested. They were all far above 20,000 PSI and one was somewhere around 34,000 PSI. After that my friend now keeps all black powder loading equipment in a seperate room from his smokeless loaders and supplies. In life things happen... Then the rumors start which are always much, much worse than the actual event. Oh, my friend's blown gun is pictured in "Shooting Flying" by Murdelack (SP?).

I believe in moderation to preserve and only push to the limit when necessary!

[Drew Hause]

Jack: could you please post an ultra close up of the barrel flats of your BNP GHE and thanks!

Bruce: in 2002 Tom Armbrust tested and the 16ga reloading group reported two batches of the old 16g Federal Game Load 1 oz 1165 fps at 9160 and 9633 psi. All I could get Federal to tell me on inquiry was "about 10,000" in order to assure funtion in autoloaders. It's called Game-Shok Game Load now http://www.federalpremium.com/products/shotshell.aspx

LTC Calvin Goddard writing in Army Ordnance in 1934, stated that Hunter Arms proof tested 12ga 2 3/4" chamber barrels at 14,300 psi.

[Bruce Day]

Drew, I suppose that's possible. I got "about 7500" when I talked to the Federal people in person at Pheasant Fest and matching fps with the published drams. But the Fed hull is a straight hull noted for low pressure, they use Fed primers, and even with fast burning powder like Hodgdon Universal at 1165 fps the pressure is only 7500 and less with well known slow burning powders like SR 4756. So what powder Federal would use to push faster than a fast powder like Universal is unknown to me. Universal has the fastest burning rate of any powder made by Hodgdon that is suitable for 16ga.

I got a list of pressures from Federal years ago, I'll see if I can retrieve it, but I don't think their "above 10,000" is correct and may have been only to placate the autoloader bunch. I remember they told me that their 12ga 1 oz Gold Medal papers are at 8300 psi, also a long way from 10,000.

[Bill Murphy]

Maybe someone would send a Damascus Parker ten to Birmingham to have it proofed for 3 1/2" shells at 4 tons. I can't remember the shot weight of that proof, but I have seen more than one Damascus Brit gun marked with that particular proof. I think the shot weight may have been 1 3/4 ounces. Phil Futrel once had a hammer Purdey ten with that proof stamped on its Damascus barrels.

[TARNATION !!!]

Originally Posted by Drew Hause

Jack: could you please post an ultra close up of the barrel flats of your BNP GHE and thanks!

Drew: Long day on the road to Montana and back. The only issue with the lifter acquired is some pitting in the bores. The rest of the gun looks pretty nice for 1881. The wood is very good. Action is very tight. The first surprise is it sits on a 1 frame, with those 32" barrels Cyl and Imp Cyl. Should be a sweet pheasant gun. The side plates, under the right light, are still holding some irridescent colors. I'm pretty pleased so far.

Back to the GHE BNP. Here are a couple quick shots. If you need better let me know and I will spend some time with it after getting some sleep.

Cheers,
Jack

[Bruce Day]

Originally Posted by Mark Ouellette

Austin,


A good friend and member of this board made the classic mistake of loading shells with PB instead of the black powder which he thought was in the MEC powder bottle. PB looks like black powder. His barrel blew on the 4th shot. He later had the remainder of those shells tested. They were all far above 20,000 PSI and one was somewhere around 34,000 PSI. After that my friend now keeps all black powder loading equipment in a seperate room from his smokeless loaders and supplies. In life things happen... Then the rumors start which are always much, much worse than the actual event. Oh, my friend's blown gun is pictured in "Shooting Flying" by Murdelack (SP?).

I believe in moderation to preserve and only push to the limit when necessary!

Paul Harm's ruptured Remington is in Ed's book at p. 119 and is accurately reported as the result of a substitution of smokeless for black. Other authors may not be so constrained and may have reported it only as what happens when you put a smokeless powder load in a damascus gun.

Maybe the point I have been trying to make, maybe somewhat inartfully, is that Parker damascus barrels are stout and if a person wants to know what he can shoot in one, detailed information is available and goes far beyond " you have to use low pressure shells and you get them from RST." You don't have to use low pressure loads, and you can buy shells from local sources that meet the Parker load requirements for the gun, if he wants to find out for himself. But I shoot moderate to low pressure loads at clays because I like to be easy on my shoulder and the gun. If a person hears that he can only use low pressure loads, seems to me that he may think that the gun is somehow weak, or inferior, or not as good as others and maybe I'm trying to put that notion to rest.

[Bill Murphy]

I think the "low pressure" caveat is in order for those who don't actually measure the wall thickness of their barrels. Some fluid steel barrels come from the factories with wall thickness that would seem to indicate the use of low pressure ammo.