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Post by rjhans53 on Jun 14, 2009 19:00:54 GMT -5
Using the NPJ breech plug I've modified a org disc bolt to pull back like the plastic jacket bolt does. I use a knight priming tool to load the 209 primer into the breech plug. The original bolt has a raised area on the face that makes the bolt longer than the new ones and it closes really tight on the primer (in fact I needed to take 1/2 a hair off of it). I shot 11 rounds today using BH 209 and CCI primers and every one went off without a hitch. Blow back is maybe 5-10% of what I usually get there is some but very little. Now one of the reason's I decided to modify an old bolt is that I've got them, they are longer and when using a priming tool you don't have the turn in edges on the end of the bolt to get in the road. This is the 2nd week of this experiment and results have been the same both times except last week I was shooting 777. Grouse if you are going to play with modifying the breech plug the biggest thing I think you need to do is make the stem a hair longer and see what happens.
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Post by robnj on Jun 15, 2009 8:40:18 GMT -5
rjhans53: I have an old original Disc too, but I converted it to use the new bolt with the NFPJ.
If I understand this... you're using the new NFPJ breech plug with the original bolt (that used to require the orange discs ) and just inserting the bare primer in the end of the new b/p with a priming tool ?
Looking at my original bolt face... I see what you mean... it does have a slight build up of steel around the firing pin. (probably to make a tighter seal when using the orange disc).
Interesting... thanks for posting this.
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Post by rjhans53 on Jun 15, 2009 11:22:50 GMT -5
Rob, yes the bolt for the orange dics. I took 1/2 of hair off the raise in the bolt face to get the bolt to close all the way.
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Post by robnj on Jun 15, 2009 15:06:49 GMT -5
rjhans53: Got it. If you go to Toby Bridges site, he has an article on the Knight Ultimate Slam rifle and in it a description of it's breech plug. From the pics and his description it appears to be the NFPJ plug, with the flash hole enlarged to .038 and a powder end that is concave with a counter sunk 1/8" hole in the middle. I'm guessing this was done to shorten the internal flame travel and provide more flame to ignite BH209. According to Toby, the new b/p is slightly longer which probably provides a better primer seal... and he says very minimal blowback. (Like you've accomplished with your modifications) Here's the link, if you haven't seen it already: www.hpmuzzleloading.com/NewProducts6.html
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Post by rjhans53 on Jun 15, 2009 15:27:07 GMT -5
I was going to buy one of those things when they came out, but it looks like that isn't going to happen. The one thing that I'm thinking of is someway to epoxy a primer holder to the face of the bolt, I'd have to figure out how to make one 1st. My guess it would work better for me that what the grand slam bolt looks like, you could get you finger in to help extract the primer if it hung up a bit. YES I have faith in epoxy holding.
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Post by robnj on Jun 15, 2009 16:03:51 GMT -5
I hear you... Toby's article mentions that even the Ultimate Slam had issues with spent primers sticking in the bolt. It certainly is an annoyance. When a primer sticks, I just snap the trigger again on it, and it always drops out after that.
Guess I'll wait and see what Dave (Lehigh Bullets) comes up with.
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Post by grouse on Jun 15, 2009 20:43:31 GMT -5
Guess I'll wait and see what Dave (Lehigh Bullets) comes up with. Did some testing this past weekend. Don't worry, you will be happy when it's done.  |
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Post by robnj on Jun 16, 2009 8:18:37 GMT -5
Guess I'll wait and see what Dave (Lehigh Bullets) comes up with. Did some testing this past weekend. Don't worry, you will be happy when it's done. Sounds promising  Thanks Grouse ! |
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