|
|
Post by artjr338wm on Oct 30, 2010 12:22:25 GMT -5
I was just wondering if a breach plug that uses a vent liner, specifically a Lehigh vent liner can cause a SIGNIFICANT enough rise in pressure to cause sabot failure.
For the first time ever I have given a standard Savage factory breach plug a try with Lehigh VLs. In the past all I have ever used was a RBnAR modified DB insert B-plug. I used a standard breach plug W/Lehigh-VLs and had several sabots shread on me.
It was worm out, but I was usung a cooling rod and I confirmed that the barrel was cool to the touch before i loaded and shot.
Has anyone else experienced a significant pressure rise who was using a DB incert B-plug then tried a B-plug with vent liners?
Thanks,
Arthur.
|
|
|
|
Post by Richard on Oct 30, 2010 16:44:42 GMT -5
Is that RB plug recessed? I would not think the Lehigh vent should make any difference. A .031" hole is a .031" hole? The little dome on those VL's should not make a difference. A recessed plug, whether using a drill bushing or vent liner will probably give you a little more velocity (using the same powder charge). I have not done much testing in this area as I have exclusively shot my own recessed factory plugs with my own drilled ).031" vent liners............Practically from when I first stated playing this game three years ago.
Richard
|
|
|
|
Post by GMB54-120 on Oct 30, 2010 18:07:30 GMT -5
Lehigh liners are .032 or .033. Im fairly sure they are .032 so just the liner shouldn't be a big difference.
But........ in a heavily recessed vent liner pocket using a Lehigh liner i have seen a increase in velocity. So pressure might be higher using those designs together. Mounted flush or near flush i havent noticed any difference even with a PR brand vent liner with a .033 hole. Maybe a bit less blowby with a domed liner alone.
This wasnt in a Savage but the same effect may occur. It is very noticeable if the vent liner pocket is larger than bore. Such as a deep .50 ID pocket in the breach plug and a 45cal ML bore.
|
|
|
|
Post by Jon on Oct 30, 2010 21:03:54 GMT -5
gmb54120. Just a question. How did you bore the plug to .500? Am I missing something?
Jon
|
|
|
|
Post by boarhog on Oct 30, 2010 21:24:16 GMT -5
Art,
I wonder if your sabots might have been exposed to warm temps on your way to shoot. Once, I had a delay leaving for the range, and my ML box was out in the sun a bit too long. Even though I was using a Kool Rod, I felt the sabot petals stretching some, and had a few fail. After I put the bag of sabots on ice for about 20 minutes, the problem went away.
Boarhog
|
|
|
|
Post by GMB54-120 on Oct 30, 2010 21:25:41 GMT -5
gmb54120. Just a question. How did you bore the plug to .500? Am I missing something? Jon Yes the part where i said it wasnt in a Savage.  Lehigh breach plugs for Knight rifles have a deep .500 ID vent liner pocket and i have one in an Elte 45. I tried a similar experiment in a CVA Accura 45 with a custom plug using .469ish pocket and got the same results. I dont think a Savage plug has enough metal to go larger than bore and just mounted near flush ive never noticed this same effect in all the non Savage plugs ive tried. |
|
|
|
Post by Jon on Oct 30, 2010 23:40:10 GMT -5
Thank you for straighten me out. I have a couple of recessed savage plugs the largest is 3/8. After that things would get pretty thin. I was just curious. I'm always looking for a better mouse trap.
Jon
|
|
|
|
Post by GMB54-120 on Oct 31, 2010 10:06:26 GMT -5
Jon
Just sharing info ive picked up on the basic designs ive tried. They may have little or no bearing on how a SML will react but it is possible IMO.
A recessed plug and a duplex load for example could have a noticeable difference than just using a duplex load and a OEM plug. The booster could fill the recess and effect how well it ignites the main charge.
Now add a domed vent liner and combine all three variables and its very likely you could get more pressure with some powders or duplex loads.
My tests in 45cals with BH209 were VERY noticeable with this design. Kind of like a bottle neck centerfire cartridge is more efficient than a straight wall.
I use mostly Lehigh vent liners in my tests and compare them to the PR liners. Neither mounted flush show any difference other than less blowby using BH209.
Other variables are more likely to have caused the pressure increase and/or sabot failure the OP experienced IMO but i didnt notice the powder he was using or if it was a duplex load.
Im still very new to the SML scene. I havent fired mine yet since it was NIB at a super good deal. Im still on the fence over selling it for a small profit. Ive only tested a couple of primers for blowby and head space. Considering the design of an OEM Savage plug i doubt i will be experimenting with it any time soon...other than just using Lehigh liners or converting it to a 45 sometime later.
I hope i did not come off wrong in my reply to you.
|
|
|
|
Post by edge on Oct 31, 2010 11:46:00 GMT -5
IMO, if you ONLY switch out a worn out VL you will often find a POI change! That is the reason I came up with using a bushing. Back then I was shooting heavy doses of Lil'Gun which took a VL from 0.031 to 0.040 in less than 50 shots!
Switching a BP from a bushing type to a VL will not make a big difference UNLESS you also clean the BP, unless you switch from a standard to a recessed or vice versa, etc.
Moderate changes make the system different.
edge.
|
|
|
|
Post by Jon on Oct 31, 2010 11:55:14 GMT -5
gmb54120. No you came off just right. I don't know if your aware or not Savage is going out of the m/l end. So if you have one I would hang onto it. If not let me know I could use one more. If you prefer b/p I have a modified remington that you may be interested in for a trade.
Jon
|
|
|
|
Post by GMB54-120 on Oct 31, 2010 13:10:05 GMT -5
gmb54120. No you came off just right. I don't know if your aware or not Savage is going out of the m/l end. So if you have one I would hang onto it. If not let me know I could use one more. If you prefer b/p I have a modified remington that you may be interested in for a trade. Jon I know the Savage has been discontinued and that is part of the reason i bought it...that and i only paid $550 for a SS/Laminate and i wanted a faster twist 50cal. The smokeless part didnt really matter other than its a strong action and smokeless grade barrel. I will likely hold on to it for awhile and see what happens with Mr Ball and customizing options he or others might offer. I wont be holding out much longer on shooting it though. Ive got some 5744 and Reloader 7 now and im dying to try some of these 325gr FTXs with the Re7. Next weekend i will be firing it with the Lehigh liners and see how well i like it compared to my Knight 52cal LRH project with heavy doses of BH209 using Barnes 458 SOCOMs. My apologizes to the OP for straying off topic. |
|
|
|
Post by sw on Oct 31, 2010 13:40:57 GMT -5
I have found that with a worn ventliner/bushing, thus a larger hole - to me 0.035" is too large for 40 and 45, the velocity goes up some, the std dev goes up, and accuracy goes down.
|
|
Lehigh breach plugs for Knight rifles have a deep .500 ID vent liner pocket and i have one in an Elte 45. I tried a similar experiment in a CVA Accura 45 with a custom plug using .469ish pocket and got the same results.
