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Post by nmaineron on Feb 19, 2010 14:30:41 GMT -5
Can we discuss the properties of the Breech plug,such as the passage sizes and the whys and why nots of their sizes.
I have been playing in my cellar with afew ideas and items trying to find a solution.The orifice sizes come into play for me because I think that when we convert from the the ole nipple #11 primer to the 209 we are overloading the orifices ability to pass the gas efficently.
I also believe that this may be a double edged sword simply because dealing with pressure and its need to take the path of least resistance.If we open up the orifices to allow more flow out are we also allowing a greater backflow of pressure through the plug?
I have been wondering if we really need the .035 orifice,in my laboratory I have found that just firing with a primer I am getting about the same amout of blowback as when I am firing behind a 100 gr load of Blackhorn.This is just perception cause I have no way of actually measuring this event but it leaves me thinking that if I could get rid of just the primer blowback,CCI M 209 BTW,that it would be interesting to see just how much is coming back through the .035 orifice when a load is in the barrel.
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Post by dave d. on Feb 20, 2010 3:48:37 GMT -5
:)nm I have been messing with these guns for a long time and my theory is alittle different then most. I have found that as my plugs foul they shoot more consistent and have less blowback. I do not drill out the crud like most do and find this works best for me in my guns. I have modified several 700 mls and have found that a tight seal at the bottom of the pocket works best with 209's and my plugs go right into a .031 flash hole. My cf converted case guns go fom a 1/8" hole to a .031 vent with zero blowback. The rem ml has such a short plug it will ignite bh with no problem once you get a tight seal as a matter of fact I bet it would ignite perfectly with a #11 if you could seal it. Work on your bolt problem that will help you out tremdously first. Here's a pic of a mod I did along time ago and this gun has absolutely zero blowback.   goodluck and I hope this helped. |
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Post by nmaineron on Feb 20, 2010 18:33:09 GMT -5
Thanks Dave,did you turn your hammer into a pin and make the bushing which it looks like you did.Did you relieve the bushing to go inside the bolt? How far?
What type of primer well are you using?
Are you burning smokeless?
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Post by urbanredneck on Feb 21, 2010 10:05:21 GMT -5
Total conjecture on my part- Leaving out the effects of gas escape past threaded parts. The "funnel effect" of modern breech plugs provide counter-pressure against the main charge. Therefore, the ideal plug/primer/charge combo is one that emits enough flame to ignite main charge and yet small enough to exert that counter-pressure as long as possible, ideally until peak pressure is reached. More conjecture- This is the crux of the Bh209 powder paradox, while the peak pressure is reported as lower yet, this peak occurs later. I believe the recommended magnum primers don't necessarily provide more force, rather they provide ignition temperature and force, longer. This is critical since the powder is harder to ignite(than black) and to maintain counter pressure a few nanoseconds longer to resist blowback as the event reaches peak pressures. All of this assumes a locked breech and firing pin system. I don't believe most unmodified slam fire actions provide enough resistance, long enough, to ever really shoot "clean". I have no idea what the ideal ratio of flash hole size : flame channel length/diameter : primer : powder is. I expect most manufacturers aim for what works best with 2 or three common powders and leave it at that. Again, I claim no expertise in gas flow engineering or internal ballistics, just some Sunday morning noodling  Jim |
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Post by nmaineron on Feb 21, 2010 13:14:55 GMT -5
Jim, I think that we have upset the balance with our experimentations and we are paving new ground to find the new balance. I believe that the mag primers do create more back pressure/force simply because they build pressure and temp. longer,but we wouldn't have any back pressure without the resistance of the oriface size.What I find interesting is that the rifle was designed to use a #11 primer and black powder or pyrodex.The flash hole was .031.Comparing this to a cutting torch,when you have a small tip you can maintain the pressures of a larger tip but you have to meter the flow back in order to hold ignition.I have been thinking that the flash hole has been restricting the gas passage yet guys like Dave have sealed the system and have left the flash hole @.031 and had no problems.Sealing the system is definately the answer.Its going to be how you do it from here on.
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Post by fletch on Feb 21, 2010 15:06:30 GMT -5
I see the benefit of using a pistol or rifle shell cut down to seal the primer fire better for both blow back and ignition. Using this idea the perfect primer system might be a reloadable, screw in system like the one PR uses with either small rifle or pistol primers. If you can handle the slower reloading for hunting. It should not be to dificult to drill and thread the breach plug to fit a small bolt machined to the right size.
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Post by nmaineron on Feb 21, 2010 15:22:33 GMT -5
Fletch,I was doing something similar to what you are talking about.I have been taking a 30-06 shell and cutting it down to the primer pocket and reaming it to fit over the 209 primer nipple.I drill the 30-06 primer out to accept the 209 primer then I slip it over the 209 nipple.Well it went well until I fired her.Backpressure forced the 30-06 case off the nipple and into the bolt.I have to reboot and use a shell like a 30-30 that has a flange on it to prevent the bolt issue.
One thing I did try was to do the above with a large rifle primer in the 30-06 case.I couldn't ignite the large rifle primer.Maybe thats a good thing....
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Post by Al on Feb 22, 2010 12:08:43 GMT -5
Fletch,I was doing something similar to what you are talking about.I have been taking a 30-06 shell and cutting it down to the primer pocket and reaming it to fit over the 209 primer nipple.I drill the 30-06 primer out to accept the 209 primer then I slip it over the 209 nipple.Well it went well until I fired her.Backpressure forced the 30-06 case off the nipple and into the bolt.I have to reboot and use a shell like a 30-30 that has a flange on it to prevent the bolt issue. One thing I did try was to do the above with a large rifle primer in the 30-06 case.I couldn't ignite the large rifle primer.Maybe thats a good thing.... you'll have to support the face of the primer, or the 209 will come out of that 30-30 case too. been there-done that. |
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Post by urbanredneck on Feb 23, 2010 10:03:43 GMT -5
Jim, I think that we have upset the balance with our experimentations and we are paving new ground to find the new balance. I believe that the mag primers do create more back pressure/force simply because they build pressure and temp. longer,but we wouldn't have any back pressure without the resistance of the oriface size.What I find interesting is that the rifle was designed to use a #11 primer and black powder or pyrodex.The flash hole was .031.Comparing this to a cutting torch,when you have a small tip you can maintain the pressures of a larger tip but you have to meter the flow back in order to hold ignition.I have been thinking that the flash hole has been restricting the gas passage yet guys like Dave have sealed the system and have left the flash hole @.031 and had no problems.Sealing the system is definately the answer.Its going to be how you do it from here on. Since the flame exists outside the torch orifice, I'm not sure how valid that analogy is... I do not think the the flame channel to orifice ratio is a great secret as there are breech plugs that clearly perform well with everything from black to BH209. The total blowback solution as I see it is twofold. Sealing the primer to the plug isn't truly solved unless the primer fits the plug like a metallic case head (cumbersome). The second aspect is the standing breech or bolt face must lock tight against the primer to prevent it from backing out- a form of headspace. My TC Triumph seemingly meets the second criteria, but, not the first. I get a little primer pocket fouling and that's it. The most interesting aspect of all the reverse engineering going on is clever folks are plowing ground that was largely passed over 150 years ago. It's easy to see why there was no "sealed" muzzleloader(I think), because when the problems and solutions are fleshed out, the solution is obvious, metallic cartridges! I'm mostly happy with my MLer so I do all my experimenting vicariously through the tinkerers who generously post their experiments on the interweb. Jim |
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Post by nmaineron on Feb 23, 2010 23:41:19 GMT -5
Jim,you are probably right on my torch analogy but that is where my thoughts were going especially when all thing weren't good and had hang fires,which I have minimized sustancially since converting to CCI M primers and BlackHorn. I am going to stay the course with the orifaces as they are.Today I tried something different.My sacrifice plug has been drilled to far so I drilled the plug out to accept a 3/8 grade eight cap screw.I drilled one end to accept a button head concave ventliner type socket head screw and drilled the primer end to accept the 209 primers.I left the well shallow so that the primer is seating hard on the bottom of the well and the flange end is protruding about a 1/16" out from the edge of the well.I took it outside where there is very little light and touched her off.I got no primerblow back at all.I will normally see the flash when I do this,never have I not seen the flash doing it this way.I can easily live with this but I probably won't.
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Post by swampmen on Feb 24, 2010 13:33:27 GMT -5
How do you get blow back from your savage when they tell you when to change the thing
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