Re: Question About Double Rifles

13 October 2004, 16:13

700 nitro

the barrels shot off face in very few rounds would be one sign the other would be both the barrels bown back like a banana off of a bugs bunny and tweety show.

another sign is the right or left barrel are crossing to much velosity causeing the bullets pathes to cross to soon

13 October 2004, 17:38

Robgunbuilder

A loud KA-BOOM followed by mucho PAIN!-Rob

15 October 2004, 02:12

<95yjcoup>

AC,

I had a Searcy 470 that had ejection problems with WR factory ammo that clocked 2275 fps. There were no visible signs of increased pressure on the cases and no ejection problems with handloads running 2160 fps. I could tell no difference in impact point shooting off the sticks---but I only fired 2 of the WR rounds because of the increased velocity and the sticky ejection.

14 October 2004, 04:01

ASS_CLOWN

Thank you.

Let me be a little more specific. With a bolt action you will get a sticky bolt long before KABOOM happens (hopefully and usually anyway).

Do you get similar "warning" signs with a double? For example, the rifle is set-up for a load which produced 40000 psi, and you have a cartridge that generated 45000 psi, would there be any signs to indicate this higher pressure load? If there are signs, what are they? Will they appear before the rifle either is permanently damaged or self destructs?

Thanks,
ASS_CLOWN

21 October 2004, 12:51

ASS_CLOWN

DigitalDan,

I am aware of the regulation load, unfortunately cordite is hard to come by these days.

The load I was shooting has shot very well in the past, ~ 100 rounds of it. It was the reloaded cases which exhibited this problem, not the first firing cases, which contained the exact same powder charge, primer, and bullets.

I think MacD37 is correct. We shall see though, as I will be redoing all the load development work again with new brass (hopefully thicker brass).

ASS_CLOWN

21 October 2004, 13:09

Hot Core

Quote:

... With PRE would I measure vertically or horizontally? I ask this because vertically (as oriented in the rifle's chamber) I will include the extractor deflection. Horizontally it would be only the chamber. ...

Hey AC, Apparently you are visualizing the PRE measurement different than I do.

I do this a bit different than Micrometers are actually intended to be used so as to increase the accuracy. Slowly "rotate" the Pressure Ring between the anvils to locate the widest diameter. I'm not sure if you would call that vertical or horizontal, but I call it a radial measurement. And I'm looking for a "Go"(rotates) vs. "No GO"(hangs) measurement.

Here is an example:

You take a fired factory case and rotate the Pressure Ring between the anvils of a 0.0001" capable Micrometer. (A 0.001" Caliper or Mic just isn't accurate enough.)

You do not want to "force" it to turn, or you can skew the Expansion value. Keep opening the anvils until the case will not "Hang" between the anvils when completely rotated at the Pressure Ring. Lets say that when the (PRE) is 0.xx56", the case will totally rotate between the anvils without hanging. Then if you readjust the Micrometer to 0.xx55", as you rotate the case, it will "lightly Hang" between the anvils at some point.

(I've only seen one rifle/case lot in 50 years that does not have a slight "high spot" during the rotation. This one rifle is the same all the way around the PRE. I believe it has as much to do with the quality of the cases as it does with the excellent match-up of the Dies and Chamber.)

Do this on 10-20 factory cases and average the value which we will say is 0.xx51" Factory PRE Average. Then write 0.xx51" MAX PRE on the box.

Take those same cases and Full Length Resize them enough so the Pressure Ring is reduced back close to factory specs. You should be able to get 6-9 reloads on these cases before "work hardening" of the Pressure Ring will mess up your data. You can not Neck Size while doing this because it does not appropriately reform the Pressure Ring.

As you develop your Test Loads in those factory cases, when you get to the same Factory PRE Average (0.xx51") STOP.

As you know, you need to use a Powder appropriate for the application.

---

There are also methods using PRE which allow a person to SAFELY develop Loads for Wildcats and therefore older cartridges that are difficult to obtain factory ammo for. However, this is not something for open discussion since it can get the Beginners in way over their heads.

The good thing about it is that it becomes "self-evident" as a person becomes experienced with PRE "if" the person is paying close attention to the details and maintains good records.

---

I reread all the advice from the experienced double rifle users above, and it seems to me they have all provided excellent information. Perhaps a combination of all the above will help you get to where you want to be without overloading.

Best of luck to you.

15 October 2004, 02:02

ASS_CLOWN

Rusty,

Thanks for the comments. Lets assume for a moment that I am working with a double rifle and attempting to work up a load for it. Lets assume further that the particular cartridge being loaded has no readily available loading data, further assumptions being that the bullets are not crossing, simulation says the load is within pressure limits, etc, etc. The concern being that an accidental over pressure may occur, since the entire exercise is being conducted in the "dark" so to speak. What I would like to know is if there are any tell tale signs that the load is actually over-pressure even though the bullets are striking where they are supposed to.

Final assumption, the lock-up is tighter than Fort Knox.

Thanks again,
ASS_CLOWN

21 October 2004, 16:20

DigitalDan

Don't recall for the moment what cartridge you're shooting AC, but are you aware of Seyfried's RX15 substitute for Cordite multiplier?