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Post by captaindad3 on Nov 19, 2010 18:58:01 GMT -5
I am still in the designing stage of making a breech plug to convert my Handi-rifle in 45-70 to a smokeless muzzleloader. I am thinking of using the Lehigh vent liners in the breech plug with 209 primers. Trying to get some opinions on length of flash hole from 209 primer to powder charge. What are the pros and cons of length? I was leaning toward making the vent liner end right in front of the primer with just enough room to fully seat the primer. Any thoughts?
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Post by edge on Nov 19, 2010 20:26:33 GMT -5
IMO, the larger the volume between the two reduces the flame to the powder and reduces pressure on the primer.
A catch-22
If you have a fully supported primer then they can be very close. If it is in a primer carrier like the Savage then if it is very close the primer may bulge from the pressure.
edge.
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Post by jims on Nov 19, 2010 20:37:37 GMT -5
I think edge is correct. I have some modified breech plugs that let the vent liner be inserted further in or recessed if you will. I like them but do notice somewhat more stickiness/buldging of primers with that modification versus the standard Savage BP.
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Post by Dave W on Nov 19, 2010 21:14:59 GMT -5
I have one MLII plug that has a flame channel approximately .7. It is critical of headspacing as Edge pointed out for primer bulging. It also gives higher velocities than my other plugs.
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Post by captaindad3 on Nov 20, 2010 18:03:40 GMT -5
I am hoping to end up using a load of 52 to 57g H4198. I need the bullet seated on the powder but not entering the throat area of the barrel for maximum accuracy (sound right?). I don't know yet how deep the throat is, but I am dealing with a 2" breechplug length. Is there a recommended diameter of powder cavity in the breech plug? Is it best to maximize it approaching inside diameter of a 45-70 case or can I make it narrower to be sure bullet stays out of barrel throat? If I end up with a ~5/8"deep powder cavity that would make flash hole ~1 1/8" long with .460 of that flash hole taken up by vent liner. Should the area behind the vent liner be drilled to 209 primer diameter or left narrower?
Sure would appreciate any and all guidance before I start machining.
Thanks
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