|
|
Post by elkman1310 on Oct 17, 2014 13:52:47 GMT -5
Well I should be in Colorado elk hunting but I am not. We decided it was to warm for the first hunt 70 deg weather don't make for good hunting.
So I have spent some time on my Douglas 45. There has been a lot of talk about getting a perfect seal on the plug. Using a Savage plug in a 50cal barrel is really not going to seal very well even if its machined dead nuts 100%. I looked at my Savage barrel and plug and I can only see where it has good contact at three places. And yes the plug shows some signs of light gas cutting. Which I believe is normal. A 45 cal barrel needs the barrel opened up to have clearance for the vent liner section so your really not getting much more of a sealing surface in the 45 cal barrel either.
I make my own plugs to work with these long cut off mag cases. I started out using regular 304 S/S after 10 shots I saw some evidence of flame cutting on the outer edges. No gas was getting by this section and the unthreaded section of the plug in front of the threads was clean. But I didn't like that.
My next plug was made from 17-4 S/S which has a RC35 I made the plug the same way. My plug uses a 5/16 recess in the nose of the plug to a depth of 1/2 inch. I turn down the vent liner to fit down inside the recess. this really helped to shorten the flame channel which is shorter than a Savage plug. Ignition with 73 grs of IMR4198 has been excellent . But this plug showed the same signs of gas cutting after 10 shoots. the plug stays tight.
So how to get a better seal. I didn't want to keep making plugs so I went with the two surfaces idea which has been talked about before. I first made a brass washer I took a old 338/378 case and turned off the rim and used only the belted part which measured .605 the hole in the breech plug is .625 so this was a close enough match. I made the washer .080 thick so I had to take that amount of the face of my plug. I checked this seal with die marker and it will give you enough crush to get a good seal. I don't like to use the word perfect so all I can say is its darn close. The brass washer held up very well for 10 shots. It showed only slight signs of any gas cutting. So yes yellow brass can make a good sealing surface . But I doubt that it would help a Savage plug enough to go to all the trouble.
Next test was with a 8mm S/S flat washer. These washers are fairly soft. I had to face off another plug again to get the correct length . This washer 8 mm washer is flat on the bottom and has a slight curve on the top and has a very nice finish. I placed the curved part forward toward the barrel. I fired 10 test shots today with the 250SST still have not got my Parkers getting a little ticked but I am really happy how well these cheap 250SST are shooting out to 410 they are deadly on our turkey swinger. I pulled the plug when I came home . The plug looked 100% clean and showed no signs of any kind of wear. The 8mm washer looked good with very little signs of wear. it shows a perfect seal around the bore area. The 8mm washers are dirt cheap they protect the breech plug and if and when you think they are showing signs of to much wear just drop in a new one. No machine work required on my part. I like that!
Last but not least I checked the vent liner. It started out at .032 using a wire gauge.It has been fired 30 times I started out with 10/60 and then straight 73 grs of Imr 4198.I checked the hole today and it has opened up to .035. I plan on shooting the same liner till I see a difference in accuracy.
Like I said in my post this works good for my plug .That's one of the draw backs of using a Savage plug compared to a plug that Jeff makes or something like I make or others that are using a CF action and some type of primer holder. I am happy with how mine is working out. Know that I have the bugs worked out on this one I will probably build a light weight hunting type rifle. The muzzle brake is the key to fun shooting. |
|
|
|
Post by Jon on Oct 17, 2014 15:04:51 GMT -5
Watching with great interest Smi Nula Jeff all seal at the back (top of the plug) like a bolt. My question as I have asked before. Does that eliminate all the problems? It sure does make it easy to manufacture?
|
|
|
|
Post by bestill on Oct 17, 2014 15:50:14 GMT -5
I really like adding thread tape to the plug definitely helps improve sealing.
|
|
|
|
Post by lakeplainshunter on Oct 17, 2014 16:34:53 GMT -5
Can you post a picture of your breechplug and shim?
|
|
|
|
Post by elkman1310 on Oct 17, 2014 18:17:56 GMT -5
I hope to get some pictures out soon someone offered to have me email them some pictures and they would post them for me. I would be willing to do that.
I see no reason to add tape to the threads. If your getting blow back onto your threads you got problems I get no blow back on any part of my plug. I was just concerned of having the sealing surface damaged after a bunch of shots.
If Jeff's plug seals on the rear of the plug with a flange he has a advantage over a breech plug that seals out in the front. The first two plugs I made for this gun were a tight fitting class 3 thread. That proved not to be as desirable at I thought. So I loose up on the thread tolerances a little so the plug has the ability to thread in easily and self center on the face of the barrel. That gave me a much better seal. For know I will stick with the 8mm S/S washer.
|
|
|
|
Post by Jon on Oct 17, 2014 18:31:46 GMT -5
Very interesting please keep us posted.
|
|
|
|
Post by Jon on Oct 17, 2014 18:32:50 GMT -5
Very interesting please keep us posted.
|
|
|
|
Post by epanzella on Oct 29, 2014 15:12:32 GMT -5
It seems there are two shoulders on the Savage plugs, one at the end surrounding the vent liner and the second shoulder further back. I understand from reading this forum that the first shoulder doesn't seal and the gas sealing is the function of the second shoulder. What is the reason for having two shoulders? It seems to me if the larger dia. was extended to the end of the plug combining both shoulders, there would be a wider contact area to seal the bore against gas cutting. Why two shoulders? Can anybody help me out here?
Ed P
|
|
|
|
Post by fishhawk on Oct 29, 2014 20:08:46 GMT -5
The extension for the vent was intended to redirect some of the pressure from the main sealing shoulder, I have no proof that it works. If your plug is trying to seal on the vent extension in a .45 or smaller, the clearance cut is not deep enough. Some of the McGowen barrels were like this, I ground less than .005" off the extension to cure the issue.
|
|
|
|
Post by epanzella on Oct 30, 2014 9:07:55 GMT -5
The extension for the vent was intended to redirect some of the pressure from the main sealing shoulder, I have no proof that it works. If your plug is trying to seal on the vent extension in a .45 or smaller, the clearance cut is not deep enough. Some of the McGowen barrels were like this, I ground less than .005" off the extension to cure the issue. I didn't cut in my BP yet. I have a 458 McGowen blank that I'm going to be fitting to a Savage 111 after this hunting season. I have the barrel blank turned to near finished OD and the next step it to thread the breech for the action/BP. I have a couple of new factory Savage plugs and I already fitted my bolt with a 209 nose. As this is my first SML build I'm trying to learn all I can about the forces at play. Measure twice/cut once. To machine for the Savage plug I have to use one of my smallest boring bars and it has to reach nearly two inches into the breech so chatter and possible gas cutting is my concern. I didn't think that Savage would add another machining step to their plugs without a good reason and you've answered that question. This is a great site and I've picked up lots of good info. I'm looking forward to being a contributor when I have something worth contributing. Thanks for the help. Ed P |
|
|
|
Post by elkman1310 on Oct 30, 2014 18:18:44 GMT -5
Seems like there still is some confusion on where the Savage plug seats. The front of the plug should mate squarely with the barrel. There is a set dimension that Savage uses. I believe it has a pretty wide tolerance. But you need to able to head space the plug.
The threads hold the plug tightly in the barrel. The plug doesn't head space on the threads. I have looked at my Savage plug and it has about a 70% contact with the inside of the barrel. That's probably normal. If you shoot a lot you will see some signs of flame cutting from the gases trying to get around the face of the breech plug. That's fairly normal.
Smokeless muzzle loaders require extra work compared to a black powder sub gun. Smokeless powders generate more heat and pressure and are harder on components. There is always a trade off for more performance.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 30, 2014 21:11:45 GMT -5
Epanzella, is your boring bar a 3/8" bar made for carbide inserts? If so you should be able to squeak by without issue. A solid carbide boring bar will help a lot with rigidity but if you are only doing one it probably isn't worth the expense. If you get a solid carbide bar be sure not to get chatter or they sometimes snap in a split second.  a steel bar will do just fine with light cuts and don't let it dwell in one spot when you cut your feed out. If you don't have dro it's a little nerve racking but you can still do it even with the most ridiculous of setups. I like to stop .010" short of my mark until the final pass and then feed in to my mark and start slowly cranking the crossfeed as soon as I stop my carriage feed to keep it from chattering. It is rewarding to do it yourself and you'll be surprised how much better it will look that some of the prefits sealing surfaces that I've looked at. |
|
|
|
Post by epanzella on Oct 31, 2014 7:24:40 GMT -5
Epanzella, is your boring bar a 3/8" bar made for carbide inserts? If so you should be able to squeak by without issue. A solid carbide boring bar will help a lot with rigidity but if you are only doing one it probably isn't worth the expense. If you get a solid carbide bar be sure not to get chatter or they sometimes snap in a split second. a steel bar will do just fine with light cuts and don't let it dwell in one spot when you cut your feed out. If you don't have dro it's a little nerve racking but you can still do it even with the most ridiculous of setups. I like to stop .010" short of my mark until the final pass and then feed in to my mark and start slowly cranking the crossfeed as soon as I stop my carriage feed to keep it from chattering. It is rewarding to do it yourself and you'll be surprised how much better it will look that some of the prefits sealing surfaces that I've looked at. Yes, my smallest indexable carbide bar is 3/8. I'm not sure if it will fit in a .450 hole so I may have to start with HSS to open the bore up a bit. I don't have a DRO but I have a 1" travel dial indicator on my xfeed and a 2" travel DI on my carriage. I also have a magnetic 1" DI that I put on my milling attachment when I need it. Not as convenient as a DRO but they work pretty well. Thanks, Ed P |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 31, 2014 8:00:10 GMT -5
I just did a .40 and I just raised my boring bar in the tool post to clear until the diameter was large enough to place it at the proper height. Have fun!
|
|
|
|
Post by edge on Oct 31, 2014 9:18:14 GMT -5
Seems like there still is some confusion on where the Savage plug seats. The front of the plug should mate squarely with the barrel. SNIP. Actually not the front, it is the face of the second diameter that headspaces the plug. It is approximately 0.616 in diameter and the mating BP dimension is about 0.605 in diameter. The 0.500 dimension is clearance for the short snout on the BP and acts as a sort of labyrinth seal. edge.  |
|
|
|
Post by epanzella on Oct 31, 2014 11:14:06 GMT -5
I just did a .40 and I just raised my boring bar in the tool post to clear until the diameter was large enough to place it at the proper height. Have fun! Meyers, good to know, thanks Ed P |
|
|
|
Post by epanzella on Oct 31, 2014 11:18:18 GMT -5
Seems like there still is some confusion on where the Savage plug seats. The front of the plug should mate squarely with the barrel. SNIP. Actually not the front, it is the face of the second diameter that headspaces the plug. It is approximately 0.616 in diameter and the mating BP dimension is about 0.605 in diameter. The 0.500 dimension is clearance for the short snout on the BP and acts as a sort of labyrinth seal. edge. Edge, That's the diagram I was looking for! Thanks, Ed P |
|
|
|
Post by Jon on Oct 31, 2014 11:44:53 GMT -5
Edge. Not trying to hijack this thread but do you feel the sealing surface if done correctly at the nose of the plug is better or sealing at the primer end of the plug with a shoulder? I could not remember the name of the labyrinth seal. Having worked with flow I would think it is a advantage IMO. Obviously sealing at the primer end is some what easier.
|
|
|
|
Post by epanzella on Oct 31, 2014 12:21:28 GMT -5
The seal is at the 1.737 inch point in the drawing. It's where the diameter goes from .500 to .616.
|
|
|
|
Post by edge on Oct 31, 2014 12:22:22 GMT -5
If you seal at the primer end you most likely are sealing on a larger contact area and that could be an advantage. The threads prevent flow also, but if you make a good seal then there is very little flow and that equates to less erosion wherever you seal it. I think you see the majority of the erosion on a Savage plug is due to the long non-threaded portion of the BP. The front end does not make a perfect seal so the area between the snout and the threads sees some pressure and that pressure leaking in causes erosion. If the threads went all the way to the end then there would be much less erosion...IMO  edge. |
|
|
|
Post by Jon on Oct 31, 2014 13:37:40 GMT -5
Thank you Edge. That would explain why on my RB plug's there is only about .125 unthreaded at the nose. The sealing area on Jeff's plug is only about .040 wide where on the standard Savage it is about .050 wide. I feel it is easier to get a good seal at the primer end. and the surface could be larger since pressure is ahead of that so the fact that the barrel would be thinner would be less relevant? If I'm correct the Savage plug was more than enough for the bullet weight and powder used at that time? But now with sabotless slow powder heavier bullets we are seeing differences? If I'm not mistaken of the plugs that you use or had influence in that I've seen drawings of although quite different than the Savage they still sealed at the nose?
|
|
|
|
Post by edge on Oct 31, 2014 14:08:32 GMT -5
SNIP. If I'm correct the Savage plug was more than enough for the bullet weight and powder used at that time? But now with sabotless slow powder heavier bullets we are seeing differences? If I'm not mistaken of the plugs that you use or had influence in that I've seen drawings of although quite different than the Savage they still sealed at the nose? All of the plugs I have designed use a shortened version of the Savage plug, in fact my first plug was simply a Savage plug with the non-threaded snout removed!  For use in a shouldered barrel.  edge. |
|
|
|
Post by epanzella on Oct 31, 2014 14:12:38 GMT -5
So is there a 209 type plug that seals better than the factory Savage? I didn't cut in my plug yet so this would be a good time to find out about a better option.
|
|
|
|
Post by jims on Oct 31, 2014 16:19:04 GMT -5
Didn't the Savage plug have the long snout to get past the recoil lug/barrel nut threaded area?
|
|
|
|
Post by edge on Oct 31, 2014 18:02:44 GMT -5
Didn't the Savage plug have the long snout to get past the recoil lug/barrel nut threaded area? Yes, that is why the short plug is only for the shouldered barrels. You can get almost the same benefits (ignition) from a recessed plug. edge. |
|
a steel bar will do just fine with light cuts and don't let it dwell in one spot when you cut your feed out. If you don't have dro it's a little nerve racking but you can still do it even with the most ridiculous of setups. I like to stop .010" short of my mark until the final pass and then feed in to my mark and start slowly cranking the crossfeed as soon as I stop my carriage feed to keep it from chattering. It is rewarding to do it yourself and you'll be surprised how much better it will look that some of the prefits sealing surfaces that I've looked at. 
