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Post by willbird on Dec 19, 2012 11:22:45 GMT -5
Decided to put this stuff here all in one place.  The rifle will be a 700 centerfire action, the BP is an evolution of a couple examples Edge posted up. Wavering between 40 and .416 calibers at present...leaning towards .416. Here is a better larger picture of the whole affair so far. i.imgur.com/sNJZ8.jpgThe case is a .473 dia, shortened to .700 long. |
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Post by willbird on Dec 19, 2012 11:29:08 GMT -5
Here is the brass I will be using for primer carriers. it is Lapua 6br brass...this photo shows the internal quality which will be an asset for what we are doing with it. Sinclair International if they have it in stock will sell small qty of this, say 6 or however many you want. I had it leftover from a 22br rifle I was playing with. This brass is so nice it is almost like jewelry :-).  Bill |
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Post by willbird on Dec 19, 2012 11:33:27 GMT -5
Next up is to machine up a prototype...and a barrel stub to fit the action, and see how extraction and feed works. Prototype will probably be O1 drill rod. I will make a steel bushing to start, but dimensions are to fit the carbide bushing some folks use.
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Post by jims on Dec 19, 2012 12:47:16 GMT -5
They make excellent, consistent brass.
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Post by ET on Dec 19, 2012 20:36:57 GMT -5
Willbird
That is an interesting design and I’m curious as to why you chose a BP with a half moon radius at the end butting up against the brass casing being employed?
I can understand the slight radius allowing easier access for guiding the primer.
Just an inquiring mind asking.
Ed
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Post by 10ga on Dec 19, 2012 20:50:55 GMT -5
Nice looking stuff. However, from the drawing, it looks like you are going to machine the brass to hold 209s? Is that correct? Wouldn't that be a weak point? How about just using LRP or MRP primers? Of course I may be somewhat confused. Perhaps I just need a bit more explanation. Thanks, 10
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Post by willbird on Dec 19, 2012 23:43:12 GMT -5
Willbird That is an interesting design and I’m curious as to why you chose a BP with a half moon radius at the end butting up against the brass casing being employed? I can understand the slight radius allowing easier access for guiding the primer. Just an inquiring mind asking. Ed That area is sort of a work in progress :-)...there will need to be some radii there to not jam things up when the case slides over the BP and the primer slides into it's pocket, exactly how big they will need to be remains to be seen. Refining it a little bit...it might look a little more like this...the radii before were at .03 and that is a bit extreme :-). Measuring the 6br brass it is a lot thicker than 45 acp brass, might have to veer back towards 45 acp brass, or go to a 8mm hex instead of 3/8..would prefer the 3/8 hex.  |
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Post by willbird on Dec 19, 2012 23:46:49 GMT -5
And yes I am machining the brass for 209's. But I do not see it as a weak point. You would have to explain why you think it is. The brass case should not see full chamber pressure. Camps seem to be about evenly split between 209's and LR primers. But with the .031 bushing, or another type of vent liner the primer should never "see" full chamber pressure as I understand it.
Bill
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Post by willbird on Dec 19, 2012 23:49:01 GMT -5
And yes I am machining the brass for 209's. But I do not see it as a weak point. You would have to explain why you think it is. The brass case should not see full chamber pressure.
Camps seem to be about evenly split between 209's and LR primers. But with the .031 bushing, or another type of vent liner the primer should never "see" full chamber pressure as I understand it.
Bill
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Post by willbird on Dec 20, 2012 0:17:00 GMT -5
OK a little more revision............suggestion was made to beef the plug up on the primer end by not making the primer pocket any deeper than it needs to be, this gives the plug more column strength that would be of benefit if there was a catastrophic plug failure. Also worked in the revised end chamfers/radii to show that better.  |
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Post by ET on Dec 20, 2012 5:31:39 GMT -5
Willbird
First thanks for your reply satisfying my curiosity.
I also have to admit I much prefer seeing your revised designed.
Now it’s a waiting game to see what results can be achieved and what can be learned. Look forward to when that happens.
Thanks for sharing.
Ed
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Post by willbird on Dec 20, 2012 7:41:34 GMT -5
Willbird First thanks for your reply satisfying my curiosity. I also have to admit I much prefer seeing your revised designed. Now it’s a waiting game to see what results can be achieved and what can be learned. Look forward to when that happens. Thanks for sharing. Ed Drawings and sketches for me are just a way to see how things fit together :-)....the final edit is always in metal :-). The primer has a fairly decent radius so maybe not much will needed to allow it to feed into the cavity in the BP. Bill |
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Post by edge on Dec 20, 2012 8:52:21 GMT -5
The 209 will enter the BP nipple easily.
While the Hex is 3/8 the rounded edges of the hex are a 0.420 diameter circle.
I think that you will find that most cases have a fair taper on the I.D.
Take a 45 ACP, the wall is about 0.013 at the case mouth but at the depth of the end of the 209 it will be about 0.025 thick.
When pushed onto the nipple there is virtually no wiggle room.
Your RED case drawing shows a straight wall on I.D. and O.D.
If you add that taper I think that not only will it be snug, but it will determine the tapered portion diameter on the end of the nipple!
edge.
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Post by willbird on Dec 20, 2012 9:50:27 GMT -5
The 209 will enter the BP nipple easily. While the Hex is 3/8 the rounded edges of the hex are a 0.420 diameter circle. I think that you will find that most cases have a fair taper on the I.D. Take a 45 ACP, the wall is about 0.013 at the case mouth but at the depth of the end of the 209 it will be about 0.025 thick. When pushed onto the nipple there is virtually no wiggle room. Your RED case drawing shows a straight wall on I.D. and O.D. If you add that taper I think that not only will it be snug, but it will determine the tapered portion diameter on the end of the nipple! edge. Ok yes......but the taper is hard to measure on an intact case. I have a set of gage pins however and some free time coming up between Christmas and new years. The rough case drawing was more about the web thickness at this time....working all the lengths out. CAD is a big help but I am still a dyed in the wool "cut and try" shop rat :-). Back at a past job we cast a lot of stuff to measure inner features....we had a melt pot of woods metal always hot....and it was right next to the optical comparator...made stuff like measuring the inner features of a 45 acp case child's play :-). My garage shop is a lot more stone age in comparison :-). |
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Post by willbird on Dec 20, 2012 11:17:56 GMT -5
OK getting a bit more real...added case taper and radius at solid head...and adj BP to fit.  Bill |
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Post by dannoboone on Dec 20, 2012 12:47:42 GMT -5
Just a head's up, not that it will hurt anything if your system does the same
as PR's breech plug system. With the PR BP, the case goes INTO the BP, so
it has quite the chamber. Even at that, upon igniting the powder, the primer
is pushed slightly out of the case and there is not enough pressure (as
there is in a CF situation) to push the case back into the bolt head and
reseat the primer.
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Deleted
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Post by Deleted on Dec 20, 2012 13:03:20 GMT -5
Is there enough material in the case to mill a ring .005 deep or so
that would mate/seal with the nose of the breach plug that would have the male side machined on it....?.just another sealing point is what I'm seeing.....
Greenhorn
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Post by willbird on Dec 20, 2012 23:16:50 GMT -5
Just a head's up, not that it will hurt anything if your system does the same as PR's breech plug system. With the PR BP, the case goes INTO the BP, so it has quite the chamber. Even at that, upon igniting the powder, the primer is pushed slightly out of the case and there is not enough pressure (as there is in a CF situation) to push the case back into the bolt head and reseat the primer. Well I am curious about that system...does it use a 209 ? In a normal primer pocket situation what you describe happens when say a LR primer fires, the pressure in the primer pocket pushes the primer out, taking up any headspace that exists. This is easily seen by just "popping" a primer. Then as pressure builds it shoves the case back onto the primer. Mild cast bullet loads will have the primer back out, and some folks drill flash holes bigger to avoid that. If the cases are machined properly we can have near zero hedspace. |
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Post by willbird on Dec 20, 2012 23:29:21 GMT -5
Is there enough material in the case to mill a ring .005 deep or so that would mate/seal with the nose of the breach plug that would have the male side machined on it....?.just another sealing point is what I'm seeing..... Greenhorn There is all kinds of metal there to do all sorts of things...but hopefully we will not need to :-) |
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Post by willbird on Dec 21, 2012 10:24:41 GMT -5
I think, the plug thread will have to go up to 11/16-16 to be able to have a decent sealing surface with any kind of powder chamber in a .416 barrel.
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Post by Deleted on Dec 23, 2012 1:05:31 GMT -5
I originally thought a 5/8" plug was going to be used for my .416 project but like you I decided the sealing surface was not sufficent so the 11/16 plug it is...
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Post by willbird on Dec 23, 2012 10:46:20 GMT -5
I originally thought a 5/8" plug was going to be used for my .416 project but like you I decided the sealing surface was not sufficent so the 11/16 plug it is... Great minds think alike I suppose hehe....and most inlines seem to use 11/16, probably for that reason. |
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Post by Deleted on Dec 23, 2012 12:38:50 GMT -5
I will however be using magnum rifle primers and primer carriers for my project. I feel the 209s are the weak link in the chain on the guns we are now using... the cups are very easily dislodged which is causing headaches for some (stuck primers) which i realize in the case system should not be a problem but I still think the rifle primers are more consistent and not nearly as dirty as the 209s...jmo
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Post by willbird on Dec 23, 2012 13:11:12 GMT -5
I will however be using magnum rifle primers and primer carriers for my project. I feel the 209s are the weak link in the chain on the guns we are now using... the cups are very easily dislodged which is causing headaches for some (stuck primers) which i realize in the case system should not be a problem but I still think the rifle primers are more consistent and not nearly as dirty as the 209s...jmo And with a lathe and mill out in the garage :-)....that option is always open if need be :-). Bill |
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Post by willbird on Dec 26, 2012 16:09:16 GMT -5
Did some machining today, made up a bbl stub and have the BP started, went 3/4-16 because that tap was handy....final build will be 11/16-16. Been awile since I machined 12L14..man that stuff cuts nice :-).
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guppy
8 Pointer
hunting buddy
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Post by guppy on Dec 28, 2012 18:51:25 GMT -5
If you need a tap let me know, I have three or four of them.
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Post by willbird on Dec 28, 2012 21:40:48 GMT -5
If you need a tap let me know, I have three or four of them. I lined up several online........hate to borrow something that has a finite lifespan :-)...,,appreciate the offer though :-) |
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Post by edge on Dec 28, 2012 23:18:00 GMT -5
With that short snout you will need two taps, one bottoming.
edge.
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Post by willbird on Dec 29, 2012 7:57:02 GMT -5
With that short snout you will need two taps, one bottoming. edge. Actually Edge in my experience, with a fine thread(and even some coarse threads)...one can run a bottom tap right in and not need a taper or plug first, did it probably hundreds of thousands, hell maybe millions of times in the last 30 years. The prototype in 3/4-16 my tap had .125 of lead on it, made the snout .150 and all was well. Bill |
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Post by edge on Dec 29, 2012 11:26:19 GMT -5
You have a good technique, average Joe is going to chip the tap 9 times out of 10, especially in stainless  edge. |
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