52 in the Rock Pit
 

I made a trip to the Rock Pit this morning to test my newly modified Lehigh Breech Plug.

Most know that i am a T7 shooter and I normally shoot an old Remington 209-4 primer (built for the 410 shotgun) as it is the weakest 209 primer that I know of. The Remington primer either the 209-4 or even the modern STS are somewhat short for the primer pocket of the Lehigh that mates best with the longer Winchester W209. The Remington works fine in the Lehigh other than it is somewhat dirty because it does not reach the primer shelf.

Well, a freind of mine in Canada, has helped me find the easy cure to adjusting the primer pocket depth. In the past I would turn SS washers down the the proper diameter to press fit into the primer pocket and with that mate the pocket to the primer and the gun. Even after turning the washer down to the correct diameter I would then have to sand the thickness down to achieve the right depth.

Brian sent me two products. one product is called 'Stainless Steel Adjusting Lengthening Shim' and comes in various thicknesses from 0.005 and up. The second product is called 'Shoulder Screw Lengthning Shim'. The come in various diameters but the one I wanted has a OD of 0.0248 - with thicknesses of 0.005, 0.015, 0.032. The OD of 0.248 works perfect to press fit tightly into the primer pocket.



I removed the BP from the 52 and installed a 0.248-0.005 shim and now the Remington Primers work perfect, as would CCI and probably Federals.

So the trip to the Rock was nescessary to check out this new modified Lehigh breech plug. The plug-shim-primer worked flawlessly...



The rifle did great also...

The first picture shows the first group of clay birds that I put out, I also grabbed a quick picture of the components I was using.

I am not sure I am 'indexing' as does everyone else might do it but I always insert the sabot with a petal looking at the ram rod.
The next picture shows the range rod down the bore. And the reason I through that in here was if anyone might be looking for a good Range Rod I believe this to be a great one and I think they are still on sale at Knight...

And the best part look how clean the the short Rem primers turned out which translate to a perfectly clean breech... I love it when a plan comes together...

I dont like the shims but they do work for a period of time. I need to tell you about what Dave is working on to correct that for Knight.

Can you share the info here? I would love to hear about it.

Yep! I am prettty sure I already know, we talked about it along time ago, think I even sent him a drawing, and renewed the discussions a few days ago. Just not sure he has the time or the market for it because the w209 is such a good all around primer.

Have you ever worn out a SS shim in the primer pocket? I have not yet. I have gas cut the leading edge of the washer but that was because I was at first unable to match the diameter of the flash channel. That has also changed especially with these SS shims.

Why the heck don't you guys just back out the breech plug a quarter or half turn?

Really not a good idea... It creates gas cutting back through the threads of the breech plug and the barrel threads. The blow back gases, especially with BH need to be stopped at the face of the BP, actually the outside edge of the face of the BP. That is why the there is a shelf in the barrel to match the face of the BP. The second problem is then the force of the blow back on the threads of BP could eventually cause metal fatigue as the BP is pushed back and forth. Eventually you might get the BP back in your....

I have tried to use this drawing to explaine/show the concept...

I just don't share that opinion Sabotloader. I don't think such gas cutting exists. With Teflon tape you may get the tape pushed back from the first thread or two, but nothing past that. If that's the case, the only real issue is crud build up in the gap left between the face of the plug and the plug stop, requiring a little extra cleaning care.

As for the force of blow back on the threads, it seems to me it is the same whether the plug is snug or not. I know some guys stop screwing the plug as soon as it contacts the stop and do not tighten it down. In that case the mechanical situation is the same as a plug backed out a small bit.

Are there any mechanical engineers out there? What are the force dynamics on a threaded bolt - tightened vs. untightened.

I suspect the critical factor is the number of threads in contact with each other, not pressure against a stop. Tightening a bolt is important so as to prevent it's loosening and backing out. But backing out is not really an issue in a muzzle loader, and clearly impossible with models such as Omegas, Knight Visions, and others where theres a breech face against the rear of the plug.

Makes you wish they had an adjustable firing pin bushing like cva & tc. Im going to have to work on this at all when my traditions comes in as it doesnt have the bushing :(

I dont use those anymore. But, if you found away to keep it tight or loc-tite it in it might last forever???

That is why the .248 OD of these new shims is great... you have to press fit them in the pocket, remember the primer pocket is .242-3. They are there to stay. It would be really hard to get them out if you could get them out.