Here are some photos and the numbers for my actual breech Plugs. The first photo is of both rifles, that these plugs are from. (
The Modifications shown below are for my purpose and use, Proceed at your own risk)
The Remington Roller was built for use with the first generation substitutes of Black Powder. ( this category to me is all Smokeless Powder)
The Knight T-Bolt was modified to use Winchester 209 shotgun primers for the express purpose of shooting BH209. (IMHO BH209 falls in to what I refer to as the 2nd generation Black Powder substitutes.)
Here are the Rifles:
The next photo is a photo of The Breech plugs from both rifles, Notice the copper based never seize in the threads. Both rifles had been pickled for storage.
The Remington's plug is the top one. This is the Plug I made from a grade 8, 5/8 bolt along with the primer holder being from a 3/8 grade 8 bolt. The powder end of this plug duplicates the shape and dimensions of the Savage Breech plug. side view only!
The lower/longer plug is the Knight's Plug, the overall length and shape of the external portion of this plug has not been altered:
The next photo is a photo of the recessed end of both plugs with Savage style vents installed.
The Knight Plug, The right plug in the photo is recessed .325 to the face of the vent screw/liner. Notice how wet the plug is from an oily bore. WOW I even dried it with a patch before the photos
The Rollers Plug, The left plug is recessed .625 to the face of the vent screw.liner. This plug also shows that My .375 drill did not want to make a perfect smooth hole on the surface, this was a Grade 8 Bolt.
The last photo is of the primer ends of both Plugs:
Knight Plug, the Rt plug again was modified before I even started the other gun. This plug has fired in over 4 pounds of BH209 and over 400 Primers. This primer seat still shows no signs of gas cutting/erosion
This MODIFIED Knight plug's dimensions: RT Plug
from end of vent screw to top of plug: 1.082"
Primer pocket recess is a depth of : .220
Distance from inserted primer to Vent : .862
(This is the distance RonL asked for I believe )
The Roller Plug: Left Plug, this plug is shorter overall. I have fired this plug over 800 times. The Primer seat shows no sign of gas cutting erosion. The grade 8 bolt is good stuff.
from end of vent screw to top of plug: .562
Primer pocket recess is a depth of : .220
Distance from inserted primer to Vent : .340 (This demention will change due to the threaded length of vent screws.)
Both plugs are stained from experiencing Hot - Flashy situations.
Did anyone catch that I threw another situation in to the pot of thoughts. Gas Cutting of the primer seat. In 03 I bought a BPI Beartooth Magnum, I fired this gun over 1200 times as a 50 cal Muzzle Loader This was with Conical Boolits Lee REALs and my maxis. The most I got out of the Soft CVA breech plugs was 400 primers. they would develop serious gas cutting in the primer seat. Check you CVA/BPI plugs for this erosion, once it starts it gets worse fast. This rifle was shot out at somewhere less than 1200 rounds, It would no longer shot accurately. I couldn't keep it on a paper plate at 50 Yards.
This BPI Beartooth Magnum Rifle today has an extended breech plug that I made, it is 17.75" long and did require that I ream the existing barrel out from the breech end to a diamater of.562. This breech plug has a hole running it's full length and this hole has stuff called rifling in it. Instead of 209s to light the powder I use small pistol primers along with 38 special or 357 mag brass. This is my version of a Rook Rifle now.