Shimming Lehigh plug for knight LRH

L&R
Shop deals on ebay
Advertise with us
Modern Muzzleloading Forum

Help Support Modern Muzzleloading Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I guess a 3rd option is the O ring provides some cushion that allows primer to be pushed forward and so not dimples as much?

Anyone ever had a problem with O rings not allowing the primer to fire?
 
Last edited:
txhunter58 said:
What do you guys think about the dimple my firing pin put in the primers above? The dirty one on the left was before the O ring. Smaller dimple on right is after.
2 possibilities I see:

1). When I took out the firing pin to test the O ring, I did something to the firing pin mech or didn’t get it put back right.

2) now that the pressure can’t blow back around the primer, it is pushing the face of the primer back more when it goes off.

Opinions? Am I OK or do I have to worry about a misfire? All of mine went off
Click to expand...
I believe it is #2. The additional pressure swelling the primer instead of blowing past. Most of mine look that way. My metal shimmed Knight does it too.
 
txhunter58 said:
What do you guys think about the dimple my firing pin put in the primers above? The dirty one on the left was before the O ring. Smaller dimple on right is after.
2 possibilities I see:

1). When I took out the firing pin to test the O ring, I did something to the firing pin mech or didn’t get it put back right.

2) now that the pressure can’t blow back around the primer, it is pushing the face of the primer back more when it goes off.

Opinions? Am I OK or do I have to worry about a misfire? All of mine went off
Click to expand...

Well, that suggestion you asked in #1 is entirely possible. There is a real possibility the firing pin assembly was not installed in the bolt housing far enough.

I would suggest you remove the hammer assembly from the bolt body. Once it is removed place it in your hand and turn the secondary safety in as FAR as it will go. Sometimes it is difficult to get the secondary safety all the way in. Now turn the hammer assembly in the bolt as far as it will go.

Here is the important thing if the assembly rotates past the alignment spot by up to a 1/2 turn then back the hammer back to alignment and release the secondary safety. If it goes farther than 1/2 way around back the assembly out 1 full turn then align.

To check your installation install the bolt in the rifle close it and pull the trigger. The pin should sick out of the nose of the bolt at least an 1/8" and the should be a very small space between the rear of receiver and cocking piece on the hammer assembly.

In this picture you can see the small space between the rear of the bolt handle and the rear of the bolt handle.

bolt.jpg


boltcomposite.jpg


Hope some of this helps

mike
 
Looking at your pictures I only see one possible problem. and that is the distance from the end of the hammer to the primer stack on the breech plug. There is going to be a lot of blow back. The BP port in the bore of the rifle is drilled slightly to deep. Shimming should provide relief, but I would think it would take more the three .005 shims.

Your bolt appears to be correct. I am assuming you are using primer adapter installed in the face of the bolt.

In this picture the top bolt shows a primer adapter installed in the face of the bolt.

3-Knightbolts.jpg


This pic shows the adapter in place and a primer dropped in and ready to pushed into the bp.

IMG-1221.jpg


This picture shows everything closed up and ready to fire.

IMG-0001.jpg


Again, just looking I think your next best bet is the shimming of the primer pocket.

Hope there is some information for you here,

mike
 
Please look at my post on previous page about shimming the primer pocket

It is a new Lehigh breech plug. I have been told the thread pocket of my gun (Knight LRH) may be deep. So may be the gun instead of the BP?

I tried metal shims first a few weeks ago. It took 3 (0.05) and I decided because it was so deep to try an O ring. Even though it is a bolt gun, that seem to work well for my shoot this weekend (10 shots) but the divit the firing pin makes with the O ring ((which completely eliminated blow back) is not as deep.

All primers went off
 
txhunter58 said:
Please look at my post on previous page about shimming the primer pocket

It is a new Lehigh breech plug. I have been told the thread pocket of my gun (Knight LRH) may be deep. So may be the gun instead of the BP?

I tried metal shims first a few weeks ago. It took 3 (0.05) and I decided because it was so deep to try an O ring. Even though it is a bolt gun, that seem to work well for my shoot this weekend (10 shots) but the divit the firing pin makes with the O ring ((which completely eliminated blow back) is not as deep.

All primers went off
Click to expand...
Ok - I was perusing the dimpled primer situation. But if all primers did ignite than that is not the problem. It continues to be the necessity of some method of shimming either O ring or shims.

I am still somewhat amazed that it only took three .005 shims to create a primer crush. I assume you were using .241x.005 shims. Eventually you will need to install at least one .248x.005 shim to hold everything in place when you are sure you are getting primer crush.

So, I am going to step off base once again. When you were shimming and testing for crush did you remove the hammer assembly from the bolt and only use the bare bolt body testing for primer crush. With the hammer assembly in the bolt and testing you can get a false reading at times.

With the hammer assembly removed insert the bolt body in the rifle then push the bolt forward to close - release the bolt handle while it is at the top and the handle should drop to the closed position and contact the receiver. Next install the shims and repeat the test with a primer in place. When the bolt drops nearly 2/3 rds of the way down and stops you should have the correct amount of shimming to create primer crush and a tight headspace.

I really should have asked what primer you are using, of course that makes a big difference in getting the correct head space. One other thing posted by Ron L. the new W209 primers are not as long as they use to be. Much closer to what the regular CCI 209 primer measures.

I am excited that you have a Lehigh 17-4 plug in the rifle versus the Knight 416 SS plug. And I really do prefer the Lehigh primer adapter.

Really hope I am not creating a headache for you!

Also, at this moment I cannot locate the picture of the extended to the BP stack that I am looking for to illustrate the distance the hammer is from the BP stack. I will continue to look

mike
 
Last edited:
Round 2 of trying an O ring to shim a knight LRH bare primer bolt gun.

I placed the O ring in the primer pocket and advanced it to the bottom of the pocket with a used cap. Verified that it was square with the pocket visually and then installed my breechplug.

Fired off 2 caps, reverified that there was a clear channel thru the breechplug and loaded up. Shot 10 times. All went boom and primer was clean. O ring still
Looks good. I think it would prob go another 10 shots with the same O ring

Looks like at least in my gun, an O ring works well and is simple to use.

On another issue, I answered my question about the reduced dimple using the O ring. Today I compared the dimple of the primers I fired before I loaded the first bullet to ones I shot a bullet with. There is a deep dimple in the primers only. Reduced ones in the ones I actually shot a bullet.

So: the increased pressure is causing the dimple to be blown back when I shoot a load.
 
By the way, I ordered 200 O rings! So if anyone else wants to try one, shoot me a PM. I can send a few out to try! Also ordered a pack of 0.248 metal
Shims. I won’t be needing them
 
There is a way to take care of the deep pocket in the barrel but will require a machinist. Get a Mountaineer plug and have the powder side machined down until you get the fit you want. The length difference in Knight plugs is all on the powder side.
 
Rubber O-rings would work but they don't long, maybe a dozen shots. As for your shimming it sounds like 4 shims is about right. Take the 4th shim out and replace it with a .248" to hold them all in place. Your bolt should drop almost all the way down and you'll feel the crush lowering it the rest of the way.
As for the primers being hard to remove try raising and lowering the bolt and dropping the hammer on the spent primer. It should come out easier.
 
Last edited:
Thanks for the tip on removing the primers! Will give that a try.

As to the rubber O rings, I rarely shoot more than 10-15 shots per session with this gun. Pretty much have it dialed in as far as powder and bullets. So far the ring looks good/intact up to that many shots. I also like being able to remove it and clean all the way to the bottom of the pocket. Tried the steel washers and like this better. So will be sticking with them unless things change.
 
One more “plug” for the Lehigh plug. With the original Knight plug, the carbon buildup in the primer pocket was substantial. Had to clean it out at about 15 shots and there was a lot of buildup. With the Lehigh, there is very little buildup.
 

Similar threads

S
New ultralight
Replies
13
Views
907
smittysmith2
S
B
Is the SSK CVA Breech Plug with Vent Liner Flame Channel Too Short?
Replies
6
Views
346
MrTom
MrTom
Chundoo
Question about shimming
Replies
7
Views
631
michiganmuzzy
michiganmuzzy
T
Wolf Question
Replies
11
Views
592
LeeCrumble
L
L
What is the length of your 5/8 18 tpi breechplug?
Replies
0
Views
213
LittleGump72
L

Latest posts

Back
Top