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I already have a reference load...factory made ammo. Why can't I just compare my reloads with them?

This is a hobby, not scientific research.

Guest

Yes it is scientific research. Depends what value you put on safety.

Member Joined: 27 Jun 2005 Posts: 1545 Location: Michigan

Guest

Well said Mr. Miles, If you are going to do this do it right.

Member Joined: 16 Nov 2006 Posts: 1338

Guest

The reason I used to pressure test was that I worked for a company that produced steel shot wads, sold Bismuth Shot and sold B&P wads. I developed loading data for all of these components. I was originally taught by Tom Armbrust, I also have worked with Alliant powders, not to develop their data, but to ensure that the steel shot loading data they produced mirrored ours, which it did.

I am not really sure how any of these fellows are developing loading data. I hear stuff like'working up loads'. You can't work up shotshell loads like you can rifle and pistol loads, by measuring case expansion. By the time you get to that point with a shot shell you are well past proof load pressures which usually 150% of max.

I assume these fellows are using the Oehler Strain Gage equipment, which is far from perfect. Or they are just looking for chronograph numbers. either way you do need reference ammo tested by a reliable ballistics lab so that you can calibrate your equipment. That is the procedure all the ammunition manufacturers follow.

The SAAMI reference ammunition is quite a complicated affair which I won't get into.

There is so much good reloading data out there I am not sure why guys want to get involved with it, unless you could afford the piezo wquipment

Low pressure, not sure why guys want low pressure, I want good consistent, loads that pattern well. Give me 9,500 - 11,500 PSI, 1200 - 1300 FPS with low extreme variations and SD and you probably got yourself a nice load.

Member Joined: 27 Jun 2005 Posts: 1545 Location: Michigan

Guest

Dave, I can't afford the fancy guns either, I shoot a $300.00 Remington 1100 16 ga I bought in 1990.

You have obviuosly done your load development the correct way, by getting Mr. Armbrust to properly pressure test your loads.

I wasn't referring to anyone shooting a Damascus barreled gun, as I have no experience with either loads or knowledge of the proof testing methods for these guns. Nor will you ever see anything written by me on the subject of reloading for a Damascus barreled gun.

That is the reason why I don't really put much thought into low pressure loads.

Guest

Dave, I believe that everyone is trying to keep you safe.

Measure the wall thickness at the chamber on your H&R barrel, then measure the wall thickness on your other shotguns. I believe the H&R is thicker, that H&R barrel is going to hide pressure, because it will not expand like the other barrels. That is the issue with the Oehler system. That is the reason you should make up reference ammo with a known pressure value, that way you can accurately persue your hobby. It really isn't that expensive or time consuming.

Please understand that I was just trying to help you out, not stop you from having some fun. Sorry if I came off that way.

Guest

Hi Tony,

You can't calibrate your strain gauge/barrel combination with hydraulic pressure, it simply takes too long and the metal will 'stretch'. Smokeless powder burns to its peak pressure in milliseconds, the metal of your chamber can't and doesn't react ('stretch') that quickly, which is the big problem with using a strain gauge system. In other words it hides some of the pressure spike. This is the major reason the the lead crusher system was moth balled and the Piezo sytem introduced.

The metal wall thickness or the type, grade or hardness of the metal, are definitely factors when using a strain gauge. Chamber dimensions also do affect the pressure readings but not enough to throw pressure findings off very much.

By the way, as long as you use the same lot numbers of hulls, powder, primers, and wads, you would be very surprised on how very close you can keep reloading for the same pressure and velocity figures. The pressure and velocity figures are tested by a ballistics lab, and then you keep correcting your equipment to those figures. That is exactly how all the ballistic labs calibrate their equipment. They take ammunition that has a known pressure and velocity run a sample before and after their regular ammunition tests and adjust the figures accordingly.

Since I believe you have never used the methods I have stated, you should try them out. While your speculations are quite eloquent, they are also quite off the mark.

Guest

I truly hope that folks understand that, I can not give detailed instructions on how and why to set-up some of this pressure test equipment up. It gets quite involved but certainly understandable for anyone that really is interested. I basically just give the important points and leave the details out of it.

I will get detailed if you want, but please one item at a time. Since I am not very good at typing. Fat fingers, gray hair and merely your middle-aged (52) average blue collar guy.

I will not comment on a subject if I don't understand it. But I do make mistakes, so please help me out when I do, as I still love to learn.

Joined: 06 Mar 2008 Posts: 596 Location: 17603

"Another indicator that muzzle region pressure has a negative effect on patterns is, if you have a barrel ported, patterns almost always improve. I believe that the choke manufacturers have figured it out also, which is why they often offer ported chokes. They really can't help muzzle jump with the ports in the choke, as they are around the entire circumferrence, but they don't allow the wad to ram into the back of the shot charge." dogchaser

Mark,
So I believe what you are saying here is that eg., the vented polychoke, with it's series of slots, progressively lessens the muzzle pressure on the wad?
And that this gradual alleviation of pressure on the wad improves patterns?
And barrel porting, again with a progressive series of holes, has a similar effect, though at least with the usual placement on the upper side of the barrel, it CAN help with muzzle jump.
Cheers,
Rich

Guest

Absolutely Russ, anything that releases powder gases before the wad exits the end of the barrel will help a shotgun to pattern better, as the wad isn't still pushing into the shot charge. You want the shotcharge in free flight as soon as possible.

Here is something that I don't understand, maybe someone else knows the answer. Sometimes you pattern one load at 1,200 FPS and it doesn't pattern as well as one going 1,350 FPS. I always scratch my head at that. I would think that there is more radial pressure at the choke, with the faster load,and that would upset its' pattern more than the slower load. nIt doesn't happen a lot, but I have seen it. Any ideas?

Assuming all components are the same, just more of a powder charge.