Todays Project - Drilling a Knight Vent Liner Out

[sabotloader]

The weather here was not good today rain and high winds... Not good for shooting

For something to do I decided I would tackle the replacement of a Knight Vent Liner in the breech plug. I had collected the bits needed - I just did not have lathe to do it on! A fellow ML shooter here in Moscow has one and I was planning on him and I doing the project together, but his lathe was on the fritz! So I decided I would use my drill press in the wood shop.

Heated the shop up and began the project. The first step in the project was to insure the drill press table was perpendicular to the chuck. Use a long drill in the chuck and a square to the table to 90*

Also - I felt it was important to slow the drill press to it lowest speed to reduce heat and provide more control. So I move it down to 640rpm.

Next I inserted a the 3/8" mill end bit in the chuck and the Breech plug in the table vice. Then I centered the drill on the hole in the vent liner. Pulled the bit down to the hole and turned the chuck by hand to confirm the etching on the vent line was equal.

After the operation began.

Placed the 3/8" Carbide Jobbers bit in the chuck and started the drilling operation. I would only drill for a few seconds and lif the bit up and out. Using compressed air I would blow the BP out and observe my progress. The observations were to insure that I was only drill Vent Liner - I did not want to drill in to the BP metal. Repeated the drill and observe steps several time. Finally I thought I could feel the bit touch the BP metal as the bit turned easier and more smooth.

Remove the Carbide bit and insterted the 3/8 x 82* bevel Mill end and cut the seat for the new Vent Liner.

Remove the Mill bit and Install a #21 Carbide Wire bit to drill out the old Vent Liner Stem to the BP flash Channel

Remove the #21 bit and install the 10x32 Tap in the chuck. Lower the Tap to the hole insert the tap and turn the chuck by hand to clean out the old existing threads and to cut a few additional threads in the BP.

Remove move bit from BP and BP from vice. Install a new Lehigh Savage Vent Liner and test for fit... All is good

He is a composite pic of the operation

Some additional pictures that might be hard to see in the Composite

This is the new Lehigh Savage Vent Liner

Project BP on the Left a new Lehigh Breech Plug on the right.

This whole operation turned out to be much easier than I expected.

 

[sqezer]

:yeah: :yeah: :yeah:

 

[Idaholewis]

Awesome work mike! :yeah: It sure is neat when we are able to be self sufficient and not depend on others!

 

[sabotloader]

Awesome work mike! :yeah: It sure is neat when we are able to be self sufficient and not depend on others!

It is really an enjoyable activity to get out in the shop and do something! and belive me there are a 1000 things that coud be done out there but I am getting to selective at my advancing age!

But, I must say it went easier that I thought - with a lathe it would really be a piece of cake!

 

[Squeeze]

A trick i have used to find center on a drill press (Iike drilling the end of a ramrod for a jag, breechplugs,etc) Is to chuck the rod (BP) in the drill, then clamp it in a vice and clamp that while still chucked tight. Release the item, by loosening the chuck, and raise the press for the bit, and it should be held perfect for center.

 

[sabotloader]

A trick i have used to find center on a drill press (Iike drilling the end of a ramrod for a jag, breechplugs,etc) Is to chuck the rod (BP) in the drill, then clamp it in a vice and clamp that while still chucked tight. Release the item, by loosening the chuck, and raise the press for the bit, and it should be held perfect for center.

If I am reading this correctly - GREAT idea... since the BP is 5/8" in diameter - I do not think it would fit in the chuck but if it did awesome way to get the center! Might need to get a bigger chuck for the press...

 

[MrTom]

When Ron posted his having drilled the breach plugs and fitted them with screw in liners I decided that I should do the same since I have an abundance of standard CVA plugs. I have mine drill and tapped to take the Savage liners and its slick, to say the least. When I started with the 209 powder I had to replace all of the conventional plugs in all of my CVA toys which really wasn't all that bad money-wise when I consider the benefit of being able to shoot the powder. I was looking, however, at still having to replace those more expensive plugs down the road so drilling and converting the old plugs made perfect sense. The liners are way cheaper than the whole plug. As Sabotloader suggested, its not hard to do and certainly doesn't take a lot of time. And then there's the satisfaction of having done something like this yourself.

I bought a CVA Kodiak last fall and bought a couple new breach plugs for it thinking I'd just shoot T7 and wanted to start with a new plug. Now I have my jig set up to drill the original plug and tap it for the liner so it too can do the 209.

There's a ton of good pictured tutorials on this site and to Ron and Sabotloader, thanks for sharing.

 

[Dougs136Schwartz]

Just curious what is the average life of a vent liner ? I'm sure it depends some on what powder

 

[sabotloader]

Just curious what is the average life of a vent liner ? I'm sure it depends some on what powder

Powder has a lot to do with it! BH will erode the contract vent liner faster than other subs. The contract vent liner should have a flash hole around 0.031 - when it gets to 0.034 you could be losing accuracy and creating more blow back pressure on the nose of the primer.

I have been getting 200+ shots with T7 powder and as mentioned with BH there is normally a reduction the number of shots.

 

[MrTom]

I haven't shot enough thru mine to really have any wear yet, so I can't say. I do believe that the replacement liners are made of a harder steel and wear well. I'll take a guess that the liners last longer than factory plugs like my CVA's. Even if the liners just last as long or as many shots as the factory plugs will the liners are way cheaper to replace. I just ordered liners and paid 22.00 for 4 of them. A single CVA 209 plug for blackhorn powder will cost me at least 25.00 before shipping and with 209 powder or T7 I don't see the plugs lasting any longer than a liner. The savings are obvious once the conversion is done.

I have a hard time believing that a factory plug won't last a couple hundred shots using the 209 or T7 powders and would expect that the liners stand up like-wise. I'll certainly have a small box with extra liners, the allen wrench needed to install the liners and a spool of Teflon tape in it in my range box that I use for my in-line shooting. I'll also have a pin gauge in there so I can easily keep track of wear in the flame hole too.

I'll also mention that I found my liners here: www.BadgerRidgeInd.com Very nice people to work with and prompt on shipping.

 

[Dougs136Schwartz]

I have 1 Knight 500 plug that Mark miller installed a Vent liner . I guess I have been spoiled and only used plugs that have bushings .(Bestill plugs) . The size of the vent /bushing hole must be more critical with 777 . I have heard many times guys loosing accuracy when their vent hole gets to big . With Blackhorn I have allowed my bushing to increase to .040 without really loosing accuracy but I start blowing primers . Thanks guys I was just curious . Sabot that is pretty slick the way you installed those vent liners . Very nice write up

 

[ronlaughlin]

Just curious what is the average life of a vent liner ?.........

Back a few years Lehigh ran out of vent liners for sale; i was forced to make my own. Now a day i still make vent liners from Holo-Krome screws. A #70 drill is used to make the flash hole. Blackhorn is the only powder i shoot. In my experience vent liner wear depends on the amount of powder burned. It seems if one is burning say 110 grain, one can expect the vent liner to last perhaps 250 or so shot. If one is burning about 80 grain powder, the vent liner may last 500, or more shot.

When the flash hole grows to 0.035" i no longer use the vent liner when using shot gun primers, because the pressure on the primer seems excessive. Excessive pressure is indicated, because soot appears between the cup, and the anvil. When burning large rifle magnum primers 0.035" flash hole seems about ideal; the vent liner can continued be used. Interestingly, to me anyway, magnum large rifle primers don't seem to erode the flash hole any further. As long as one prevents the primer seat from flame cutting, one should be able to use the same breech plug/vent liner forever, if one burns large rifle magnum primers.

 

[MrTom]

I tried drilling the screws you mention Ron and did not do well. Those tiny bits are tough to control in my drill press. I have about 60-70 of the screws if you'd like them Ron, you can have them. I'd need your mailing address. PM me with instructions if you'd like them.

 

[sabotloader]

I have 1 Knight 500 plug that Mark miller installed a Vent liner . I guess I have been spoiled and only used plugs that have bushings .(Bestill plugs) . The size of the vent /bushing hole must be more critical with 777 . I have heard many times guys loosing accuracy when their vent hole gets to big . With Blackhorn I have allowed my bushing to increase to .040 without really loosing accuracy but I start blowing primers . Thanks guys I was just curious . Sabot that is pretty slick the way you installed those vent liners . Very nice write up

Doug I have been installing Lehigh Domed Vent liners for years in regualr breech plugs form various rifles. With those plugs all it takes is regular drill bits, Quick and easy! This was the first time I had gone after a hardened Lehigh contract vent liner installed permantly in a BP.

It was not nearly as difficult as I thought it might be... since this I have done five more BP's using the same equipment - I am really getting better at the job.

I have thought about Bestill plug - for sure it is better than the the plugs I am using well there is a bit of hesitation there also. The orginal Lehigh plugs built for Knights was made out of 17-4 Stainless Steel which is a much better metal than the the 416 SS now being used - BUT... it is more expensive also. Also the original Lehigh of 17-4 came with a Lehigh Vent Liner built for a Savage smokeless shooting. It was a different material and hardened to a different hardness than the contract liners. I have 3 of 4 of them that I am well past 500 shots on.

The length of the bushing in your plug, in my opinion, is a big advantage in the area of durability and blow back pressure as compared to factory breech plugs.

 

[Dougs136Schwartz]

500 shots is outstanding . That's about the most I can get out of any 209 plug .

 

[sabotloader]

500 shots is outstanding . That's about the most I can get out of any 209 plug .

Can you just replace the bushing or do you have to go to a new plug!

 

[ShawnT]

500 shots is outstanding . That's about the most I can get out of any 209 plug .

Can you just replace the bushing or do you have to go to a new plug!

The Bushing in the Bestill Plug is held in place with a lock screw that is loctite in place. Just a little heat and you can remove the lock screw and replace the bushing.


I was planning to ask some of you about the amount of wear per # of shots that you are seeing with a ventliner, but see it is being discussed here now. I am most interested to see how many shots it takes to get from .031 flash hole (Lehigh) to .035 or there about.

Do you feel it is "Just Power charge" that causes the erosion or does type of primer (Popping Primers only) and number of primers also contribute to the erosion, how about bullet weight and or tightness of the bullet/sabot combo?

I have just started testing a new BP for the Knight KRB7 that has a ventliner in it, plus o-ring. I first popped 14 primers (Win209, RemSTS, Fed209A, CCI209, CCI209M) at home to test o-ring seal, then on first range session of testing I fired 37 shots with all the mentioned primers so a total of 51 primers fired. Charge was 120Gn V of BH with 300gn Bullets.the Lehigh Ventliner was .031" when installed and after the first range test it was then .035 per my pin gauges, that much erosion surprised me. :shock: :huh?: I was not testing for accuracy that day (it was 31* and very windy coming in of the ocean) and was only shooting at 50 yards. I was also "Curing" my bore that had just been coated with DynaTek bore coat too so it did load a bit harder than it originally did but the bore is kind tight anyway like the UL.

Hoping to do some testing tomorrow on the plug and a new size o-ring but they are talking windy and some snow in the am, so who knows. Hate chasing patches, targets and rags around the range.

 

[ronlaughlin]

.........Those tiny bits are tough to control in my drill press......

Aren't they. Put too little force on them, the screw gets work hardend; the drill dulls then breaks. Too much force, the tiny drill breaks. Frustrating it is.

 

[sabotloader]

500 shots is outstanding . That's about the most I can get out of any 209 plug .

Can you just replace the bushing or do you have to go to a new plug!

The Bushing in the Bestill Plug is held in place with a lock screw that is loctite in place. Just a little heat and you can remove the lock screw and replace the bushing.

Good to know!

I was planning to ask some of you about the amount of wear per # of shots that you are seeing with a ventliner, but see it is being discussed here now. I am most interested to see how many shots it takes to get from .031 flash hole (Lehigh) to .035 or there about.

It really depends on which version of the Lehigh Vent Liner you have... I can only speak to the original liners that Grouse and Dave built which were built to smokeless standards and the version that Lehigh built for Knight Rifles. The original version is one tuff liner especially when used in a BP or BP sub rifle. But, also remember most of my shooting - the bulk of it has been done with T7 which is not as erosive as BH. BH is so much hotter. The second factor is I do not use Mag 209 primer - I have pretty much used the old Remington 209-4 or the W209.

Do you feel it is "Just Power charge" that causes the erosion or does type of primer (Popping Primers only) and number of primers also contribute to the erosion, how about bullet weight and or tightness of the bullet/sabot combo?

I really believe it is the temperature of the burn and the pressure created by the primer and the load. Theoretically, because BH never reaches the peak pressure of T7 it should have less effect but, BH burns so much hotter. And I feel the same thing about Mag primers. I also think Ron has a REAL valid point in mentioning that LPMP's have even less effect.

I am going to say that popping primers through the liner is not an abnormal erosive effect on the liner. I have not seen any evidence of that but to be honest I have never tested for it.

I have just started testing a new BP for the Knight KRB7 that has a ventliner in it, plus o-ring. I first popped 14 primers (Win209, RemSTS, Fed209A, CCI209, CCI209M) at home to test o-ring seal, then on first range session of testing I fired 37 shots with all the mentioned primers so a total of 51 primers fired. Charge was 120Gn V of BH with 300gn Bullets.the Lehigh Ventliner was .031" when installed and after the first range test it was then .035 per my pin gauges, that much erosion surprised me. :shock: :huh?:

That would be totally unexpected by myself - but I think I remember Ron saying he has a vent liner go bad in a 100 shots.

I believe Lehigh is in the process of making a new run of vent liners now, they are currently out, I also believe that these will be the 'smokeless' variety which are mush stronger and expensive also.

I was not testing for accuracy that day (it was 31* and very windy coming in of the ocean) and was only shooting at 50 yards. I was also "Curing" my bore that had just been coated with DynaTek bore coat too so it did load a bit harder than it originally did but the bore is kind tight anyway like the UL.

That could have been part of your problem also because to heat cure you were probably shooting the loads as quickly as you could load them - not much cooling between shots was occurring.

Hoping to do some testing tomorrow on the plug and a new size o-ring but they are talking windy and some snow in the am, so who knows. Hate chasing patches, targets and rags around the range.

Hope you get out to shoot... I tied up for the weekend - grandaughter is in a softball tourney - might be able to get out on Sunday... need to do some bullet testing Sunday - I hope!

 

[ShawnT]

Mike,

After seeing how you did your conversions I have been looking around for those bits, but would probably only use them one time so that's my only hang up with getting them. I would like to drill out my original Knight BP from my UL to save as a "just in case spare". Never know when you might drop one and damage it when away on a hunt.

I was thinking along the same lines, that it is a combination of load and primer together. Primers don't make that much pressure on their own, without a load in front, but it is surprising how much the do make too. With my sealed up breech plug they will move a ramrod with a patched jag about 7 to 8 inches in this KRB. I was curious about the debris from them though going through the flash hole, if it would have a small "Sand blast" effect.

I did not really think about the fact that I was shooting about as fast as I could to cure the bore coat though, but that does make since. I would not normally shoot that way. If I remember right I shot 14 or 15 loads as fast as I could, and with a 120gnV charge....Well it would be warm. :wink:

This is actually my first time using the Ventliners, so have nothing to base wear on. I have a couple of Lehigh plugs that I got just in case I would happen on a old Disc 1 in 20 or the like, but I got them before Bestills plug came out and I have one of his in my UL. :yeah: I did put that Ventliner in the plug for the next round of testing but now I think I may just take it back out and install a new one so I can compare it to normal shooting.

As for which vintage these Lehigh Ventliners are, they are new manufacture. I got the first 2 from ASG in December and then got 4 more last month from Lehigh. ASG don't carry them anymore. I also got 4 (IIRC) of the flat head savage type from ASG as well. Got them to make sure when the plugs were made that both type would work. Those have a .028-.029 Flash hole, but I only shot 8 shots to test ignition and at the moment I don't remember it growing any.

It is supposed to be blowing up to 14 MPH tomorrow which is not bad but it is also supposed to be blowing some snow too so it will be a wait and see if I can go. What hurts is when that wind comes in off the ocean, it can be down right cold then. Next weekend the club has matches and the next is closed for our annual cleanup and repair weekend.