Questions - Knight Power Stem....
 

Been a little chatter on another forum about Knight BP's and it has sparked an interest...

The Power Stem... Has anyone shot this BP?

I am really wondering about 'blow-back'...

Here is what i might be talking about... One of the reasons that the new BP works so well in the Vision is that it has a 11/64ths flash channel a little bigger than the normal 1/8 or 8/64th. It appears that this larger and slighly longer flash channel swallows up the blow back more effectively than the small cavity - this extra bit gives the bullet a chance to get out of the barrel which then completely reduces blow back to zero.

Just a few minutes ago - I was looking for the correct bit size to ream the flash channel in a FPJ BP. I have a Power Stem BP laying here on the counter - when I dropped the bit in the flash channel it swallowed most of the length of the bit. It would make a lot bigger blowback chamber - so it might result in a lot less blowback...

I know the Power Stem works well with T7 even increases velocity significantly. I think Toby declared it a non-worker for BH, but it really has peaked my couriosity.

So again anybody with experiance outthere with the Power Stem?

Gotta say there Sabotloader, I have never heard of this before.

I do own a Knight Vision and am very found of it. It will be my primary ML this season.

rafsob

Gotta say, you are not the only one - I have posted this same question on 3/4 boards but no real replies yet. Guess it is just not used that much...

Here is a little information..

http://www.cabelas.com/p-0067239215489a.shtml#customer-product-reviews

I guess I am really thinking this might stop a lot of blow-back in the DISC series gun. It does not help you any with a Vision but your flash channel has already been opened up more to handle some of the blow-back.

Power Stem Breech Plug

• Fits .45, .50 and .52 Caliber DISC Rifles
• PowerStem accuracy enhancement increases velocity/energy, reduces felt recoil and results in more efficient powder burn.
• Use loose powder only - DO NOT use with pellets!
• Uses Full Plastic Jacket
• Hex Head

Sabotloader

You may have read this article by TB. It peaked my interest. Just bought a power stem today at Cabela's for $14. I'm going to give it a try this weekend with T7.

http://www.hpmuzzleloading.com/Technical3.html

Have you tried it yet?? kl

klundin2000

Be sure and let me know what you find... I would really appeciate it...

Sabotloader

Yes I have used that plug with my 45cal SS Disc Elites.

I can't remember a great deal of difference in blow-back. But I was using large volumes of powder:

120g-150g of 2Fg Trip7 and 3Fg Pinnacle. Igniting the charge in the exact "Middle" was supposed to get the powder burning in both directions+ backwards and forwards, this caused a cleaner, more efficient burn of the powder. And I always got about 80-100fps more than the standard plug.

I also noted that it didn't take long for the Stem plug to erode the flash port, and start to open up a bit.



However, although the Green Mountain stainless steel barrels are very strong, shooting multiple "Heavy Stem Loads" Of Trip7 actually MELTED a shallow "Halo" inside the bore, exactly at the stem ignition point. You could see it with your naked eye and feel it with a tight patch and ramrod.

Now, I never heard any reports like this with the 50cal guns. probably cause there is less pressure build up in them compared to 45cal guns.

Sabot loader there has been some info on here about it, when it first came out, it was designed for T7 suppose to be able to burn more powder with out blowing any out of the barrel. When BH209 came out somebody posted a warning that it would not work with BH. As I remember a few people really liked it but they did not seem to catch on over all. Lee

The late Elmer Keith designed a stem that went forward from the primer pocket in rifle cartridges, to ignite the charge near the front. His thought was that it would be more efficient and allow more energy from a given charge of powder. I know he did this with the 35 Whelen cartridge. I believe his experiments were during or just Before WWII He was working in one of the army armeries. and brought it up to the engineers to improve howitzer rounds. he was laughed at. Shortly there after an engeneer in that Armory had this great idea of extending the flash hole forward via a tube to better ignite the charge in Howitzer rounds and also for the big navel guns. Elmer was screwed out of his Idea, and invention.

The power stem isn't a new Idea, I believe it is a very good Idea, and it does work.

Only had an hour to shoot today but I tried the power stem breech plug today with loose T7 fffg powder. On the range it seemed to work great. Only shot three 3-shot groups with it, but two of the three groups measured just under an inch.

Knight Long Range Hunter

250 Barnes MZ, 89.1grains (weighed) of 777 fffg, T7 primer.....0.963" c-t-c

300 Barnes MZ, 89.1 grains (weighed) of 777 fffg, T7 primer....0.993" c-t-c

300 PT Gold, 89.1 grains (weighed) of 777 fffg, T7 primer....2.7" c-t-c

Guess my LRH likes those Barnes bullets with the Harvester EZ sabots.

I didn't have my chony with me but the velocity seemed higher than with 78.1 grains of Blackhorn. Both of these weights are suppose to equal 110 volume measured.

I had an absolutely terrible time getting my power stem out of the ML for cleaning. It froze up tight tight tight. kl

klundin2000

Thanks a ton for the information...

Had you greased or used to teflon to install the BP?

Hi Sabotloader

I would say I lightly greased the threads before I left for the range. I have used Blackhorn 209 for the last year and grease seem to be...well...a waste of grease. The only reason I would stray from Blackhorn 209 on occasion is ignition in very cold weather. Last year I was ML hunting in the UP of Michigan and I had about a 1/2 second of hangtime. Granted...I loaded my Knight up two days earlier, it still scared me a little. Thats when I started looking at other breech plugs and powder combinations. I'm interested in a breech plug designed by Dave that is on this site.

I do not like using that Knight plastic primer holder. I'm get blow back. For the last couple weeks I have been using the non plastic breech plug with great results...but I'm unsure on how the smaller flash hole will effect powder ignition in cold weather. When I experienced the slight hang time I was using the CCI M primer. kl

klundin2000

I leave mine loaded all the time and have never had a problem, but I am shooting T7 - Bh should be less effected.

I am hoping that the new BPlug is out soon - tom and I suppose to get the first couple for testing, but I am still not sure that I will use it since I do not shoot a lot of BH - I prefer the FPJ for handling and weather proofing - there is blowback but hunting with it is no big deal - just at the range when you are shooting shot after shot.

You can open that flash hole to .032 so you can shoot BH reliably, but that will or can/may also make your primers go pregnant in the nipple that might make them difficult to get out. Bigger hole more blowback pressure.

Lane

Wow! that could be interesting especially with the loads you normally shoot.

I would think that the Rem STS's might expand and contract more than any of the aluminum battery cups. So they might be easier to get out after shooting.

Brief summary= Don't drill out/enlarge the NFPJ to .038 and use heavy loads listed below:(:violin:



Well the STS's blew their tops:eek:, and would not eject. had to disassemble the bolt to get them out.(They worked fine before, but ejected very sticky/hard)

The CCI standard primers held together, but would not eject without bolt dis-assembly. They got too FAT:eek2:

The Winchesters looked great, but would not eject with-out really shaking/rattling the bolt. They also got a little fatter. (much worse than before plug modification)



Chrony stats: Cloudy/78 degrees

120gV=86.4gW BH209. pushing 200g ShockWaves, in MMP Cream/Tan Sabots. Chrony at 10feet from muzzle.

Winchester= 2393fps
(With Harvester smooth Blue Sabot=2389fps)
(with Green supplied sabots=2380fps)

STS= 2390fps

CCI= 2380fps

Also launched some 175g XTP type bullets in the MMP Cream/Tan sabots with the same 120gV/86.4gW charge BH209, Winchester primers=2460fps


All charges ignited instantaneously.

Just be patient fellows.:s4: