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Post by carlv on Mar 1, 2009 7:36:22 GMT -5
I see that Cecil is offering "step-drilled" vent liners, where the primer side is larger than the actual orifice. Anyone see an advantage to this? It certainly would be easy to drill them that way. Thanks, Carl (did I mention that I love the spell check feature on here?  |
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Post by dave d. on Mar 1, 2009 9:10:51 GMT -5
:)carl i'm not %100 sure what your talking about but i'll take a stab at it.if you mean he opened up the flame channel between the primer and ventliner what size did he open it to?typically it's a 1/8" hole and in my testing with my modified plug that excepts a acp case primed with a lrm the less volume gave me better ignition.i know 209's give more flame so maybe some of the experts here could give a better answer.
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Post by screwbolts on Mar 1, 2009 9:20:48 GMT -5
The last vent liners I got from Savage have a long tapper to the fron of the hole. take a look at the Photos of the breech plug that "Bigmoose" posted a while back, notice the vent liner end, it shows in these photos I believe.
I just did a quick search and can't find the photo I mentioned, but someone just pasted a photo of a vent liner recently that showed the taper. I don't believe my camera will focus close enough to get a photo to show, I may try it later.
Ken
CNY
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Post by ET on Mar 1, 2009 10:22:38 GMT -5
Carlv
I agree with your comment about the stepped vent liner being easier to drill. But now you are reducing the erosion length of the vent liner. So I see quicker erosion wear on the vent liner IMO if they are of the same material and hardness.
I look at it this way.
The vent liner is 3/8” long, .375”.
The allen head hole is roughly .100” deep so erosion length is now .275
Remove another .120” depth for a step and you now have an erosion length of .155”.
Okay now remove that step operation of .120” and just add a small chamfer depth of say .035” tops for flame funneling and you now have an erosion length of .240”.
You can make your own assessment of which vent liner you believe will function better. Also if you want to increase the flame intensity to the powder another option is having a recessed vent liner or drill bushing in a BP. Modified recessed vent liner was my choice.
Ed
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Post by dave d. on Mar 1, 2009 10:44:20 GMT -5
:)boy i was way off i guess i was having one of those moments ;D ;D ;D.good thing the members here that new what you were talking about set it straight.i agree with et on this one a small chamfer.
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Post by ET on Mar 1, 2009 11:26:20 GMT -5
Picture of Interest. On the left is a Savage vent liner example and on the right is a vent liner of my making with a small chamfer to help direct/ funnel the flame.  Ed |
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Post by Harley on Mar 1, 2009 15:02:40 GMT -5
My BP is like ET's (recessed and VL). No chamfer on the VL, though. Ed, how do you achieve the chamfer?
Harley
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Post by ET on Mar 1, 2009 16:46:16 GMT -5
My BP is like ET's (recessed and VL). No chamfer on the VL, though. Ed, how do you achieve the chamfer? Harley I just used either a 9/64 or 5/32 drill (cant remember which one) and lightly applied it until the desired chamfer was achieved. My jig for housing the vent liner for drilling has the screw basically sitting flush in it. I just reverse (flip) the jig making sure the screw was sitting on top of metal to keep it from backing off when chamfering the hole. Ed |
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Post by Harley on Mar 1, 2009 17:12:53 GMT -5
Thanks, Ed; that's what I thought you'd say; just wasn't sure of the bit size.
Harley
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Post by carlv on Mar 1, 2009 17:44:04 GMT -5
Thanks guys.
Thanks Ed, for the picture which makes it clear as a bell now.
Carl
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Post by ET on Mar 1, 2009 20:11:32 GMT -5
Guys it's my pleasure to share or contribute anything beneficial I have to offer.
Ed
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